Review One year in review 2020: comorbidities, diagnosis and treatment of primary Sjögren's syndrome

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Review
                One year in review 2020: comorbidities, diagnosis
                 and treatment of primary Sjögren’s syndrome
                   V. Manfrè1, G. Cafaro2, I. Riccucci2, A. Zabotti1, C. Perricone2,
                               H. Bootsma3, S. De Vita1, E. Bartoloni2

1
  Clinic of Rheumatology, DAME,                ABSTRACT                                     Clinical phenotypes and
University Hospital Santa Maria della          Primary Sjögren’s syndrome (pSS) is          comorbidities
Misericordia, Udine;                           a complex and heterogeneous disor-           Glandular manifestations
2
  Rheumatology Unit, Department of
                                               der characterised by a wide spectrum         Involvement of the exocrine glands
Medicine, University of Perugia, Italy;
3
  Department of Rheumatology and               of glandular and extra-glandular fea-        represents the main feature of pSS. In a
Clinical Immunology, University                tures. The discovery of novel biomark-       recent analysis of a prospective multi-
Medical Centre Groningen, University           ers allowed to characterise the disease      centre Spanish cohort of more than 400
of Groningen, the Netherlands.                 not only phenotypically on the basis of      pSS patients, about 94% complained
Valeria Manfrè*, MD                            clinical presentation, but also on the ba-   dry eye or dry mouth symptoms at
Giacomo Cafaro*, MD                            sis of the endotype. Moreover, a better      diagnosis and around 30% of patients
Ilenia Riccucci, MD                            stratification of patients has important     presented with unilateral or bilateral
Alen Zabotti, MD                               value in the evaluation of mechanisms        parotid gland enlargement (6). Moreo-
Carlo Perricone, MD, PhD
                                               underlying the risk of lymphoprolifera-      ver, the severity of sicca symptoms
Hendrika Bootsma, MD, PhD
Salvatore De Vita, MD                          tive disorders in these patients. Finally,   may hamper the quality of life. Dry eye
Elena Bartoloni, MD                            novel targeted therapies may open new        in pSS has more severe clinical course
*These two authors equally.                    possibilities for the application of per-    and functional damage in comparison
Please address correspondence to:
                                               sonalised medicine in pSS.                   to non-SS dry eye. In order to better
Salvatore De Vita,                                                                          characterise features of dry eye in pSS,
Clinica di Reumatologia,                       Introduction                                 Yoon et al. performed a cross-sectional
Dipartimento di Medicina (DAME),               Primary Sjögren’s syndrome (pSS) is a        study evaluating 91 pSS diagnosed ac-
ASUFC Università di Udine,                     chronic systemic autoimmune disease          cording to the 2012 American College
Piazzale Santa Maria della                     characterised by a wide spectrum of          of Rheumatology (ACR) criteria and
Misericordia, 15                               clinical features, extending from exo-       55 non-SS subjects with dry eye (7).
33100 Udine, Italy.
E-mail: salvatore.devita@asufc.sanita.fvg.it
                                               crine involvement to extra-glandular         Markers of ocular damage, including
                                               manifestations. Growing efforts have         tear break-up time (BUT), Schirmer
Received on June 29, 2020; accepted in
revised form on July 29, 2020.
                                               been made during the last months to          test I and corneal/conjunctival staining
                                               deeper characterise the disease, its         scores, were significantly worse in pSS
Clin Exp Rheumatol 2020; 38 (Suppl. 126):
S10-S22.                                       pathogenetic pathways and ultimate           patients. Moreover, Authors compared
                                               searching for novel biomarkers that          the characteristics of dry eye in pSS pa-
© Copyright Clinical and
Experimental Rheumatology 2020.                may allow an earlier diagnosis and a         tients who did and did not satisfy the
                                               more precise therapeutic intervention.       2016 ACR-European League Against
Key words: Sjögren’s syndrome,                 In this review, following previous oth-      Rheumatism (EULAR) classification
lymphoproliferative, salivary gland            ers (1-5), we will summarise the most        criteria. Interestingly, there were no
ultrasonography, comorbidities,                recent literature on SS clinical presen-     significant differences between the two
therapy                                        tation, diagnosis and treatment. More-       groups in immunologic parameters as
                                               over, interest will be directed to the       well as ocular surface scores while fo-
                                               analysis of recent literature on lym-        cus score was higher in the group of
                                               phoproliferative risk and application        patients fulfilling the 2016 ACR/EU-
                                               of salivary gland ultrasonography as         LAR classification criteria (7). These
                                               diagnostic tool. Finally, we will high-      data were further confirmed in a case-
                                               light the state of the art of pSS therapy.   control study comparing features and
                                               In this perspective, we have performed       medical and occupational history in
                                               a Medline search of English language         patients with pSS, dry eye syndrome
                                               articles published in the PubMed da-         and B-cell non-Hodgkin’s lymphoma
                                               tabase from 1st January 2019 to 31st         (8). Primary SS patients were charac-
Competing interests: none declared.            December 2019.                               terised by an increased dryness sever-

S-10                                                                                         Clinical and Experimental Rheumatology 2020
One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

ity in comparison to subjects with dry        of plaque and gingival bleeding. A re-      specific. Even though lung involve-
eye syndrome and healthy controls (8).        cent population-based study found that      ment may be present in nearly one fifth
Interestingly, some novel autoantibod-        patients with PD have a 50% increased       of patients, it is often under-evaluated
ies, including anti-salivary gland pro-       risk of subsequent pSS, thus suggest-       despite its important clinical implica-
tein 1 (SP1), anti-carbonic anhydrase 6       ing that immune-mediated inflamma-          tions. Moreover, patients with pulmo-
(CA6) and anti-parotid secretory pro-         tory mechanisms may contribute to this      nary involvement have a decreased
tein (PSP), suggested as useful markers       association (12). However, conclusive       quality of life and an increased mor-
to identify pSS patients at early stage,      evidence regarding increased risk of        tality as compared to patients with-
may be associated with dry eye occur-         PD in pSS patients is lacking. A recent     out lung disease (15, 16). Respiratory
rence in these patients. In particular,       meta-analysis and systematic review         tract involvement in pSS may cause
anti-CA6 were associated with severe          evaluated PD prevalence in a cohort of      tracheal, bronchiolar, and pulmonary
aqueous deficient dry eye (9). Howev-         228 pSS patients (13). Outcome meas-        complications including xerotrachea,
er, future longitudinal larger studies are    ures included plaque index, gingival        bronchiolitis and bronchiectasis, pul-
needed to evaluate their specificity in       index, pocket-probing depth, clinical       monary cysts and bronchus or lung-
screening dry eye subjects for SS.            attachment loss, decayed missing filled     associated lymphomas (16, 17). In-
Dry mouth represents an adjunctive            teeth and decayed missing filling sur-      terstitial lung disease (ILD) has been
discomfort in these patients and sig-         faces. No significant increased risk of     reported in 3-11% of pSS patients and
nificantly affects oral health. There are     PD was observed in pSS patients in          represents a significant cause of mor-
data supporting a link between low sal-       comparison to controls except for high-     bidity due to its variable course. Non-
ivary flow rates and increased risk for       er susceptibility to caries in the former   specific interstitial pneumonitis (NSIP)
dental caries both in pSS patients and        group.                                      is the most common subtype, followed
in subjects with other causes of sali-                                                    by usual interstitial pneumonia (UIP),
vary hypofunction. A recent retrospec-        Take home messages                          lymphoid interstitial pneumonia (LIP)
tive study compared the risk factors for      • Dry eye is more severe in patients        and organising pneumonia (OP) (16).
caries between patients with pSS sali-        with SS, compared to subjects with          Considering that patients with pSS-
vary hypofunction and subjects with           non-SS dry eye (7, 8).                      ILD may have a different prognosis,
non-SS salivary hypofunction (10).            • PSS patients have higher prevalence       researchers focused on factors predic-
The pSS group had a significant higher        of dental caries, probably not only due     tive of ILD development at disease
number of total caries in comparison to       to hyposalivation but also to altered       diagnosis. Among these, older age,
other groups. Interestingly, in the pSS       mouth microbiota (10, 11).                  Raynaud’s phenomenon and oesopha-
group, a focus score greater than 1 was                                                   geal involvement have been identified
the only factor associated with a great-      Extraglandular manifestations               as predictive factors associated with
er number of total caries (10). Thus, the     There is growing awareness that extra-      poorer outcome (15). In a retrospec-
increased risk of caries in pSS patients      glandular manifestations represent a        tive multicentre study including 99
is not sufficiently explained by salivary     clinical challenge in pSS patients due      pSS patients with ILD, Kamiya et al.
hyposalivation, and other pSS-related         to the heterogeneous clinical presenta-     demonstrated that elevated serum lev-
factors should be investigated. In this       tions. The analysis of a huge interna-      els of Krebs von den Lungen-6 (KL-6),
setting, a recent study explored the as-      tional cohort of pSS patients enrolled      a mucin-like glycoprotein expressed
sociation between low salivary flow           in the Big Data Sjögren Project Con-        on type II alveolar epithelial cells, are
and altered oral microbial homeostasis        sortium registry showed that more than      associated with higher mortality rate
in pSS patients, non-SS sicca symp-           a quarter of patients may have systemic     (18). In addition, lower forced vital ca-
toms and healthy controls (11). The           manifestations not currently included       pacity and older age at diagnosis were
analysis of oral microbiota revealed          in the EULAR SS Disease Activity            significantly associated with worse
dysbiosis in the salivary microbiota          Index (ESSDAI), cardiovascular (CV)         survival (18). Chest high-resolution
from pSS and non-SS patients com-             manifestations being the most frequent      computed tomography (CT) patterns
pared to healthy controls. In particular,     (14). Moreover, although many of            may also suggest worse outcome. In a
the salivary microbiome in the pSS            these manifestations are usually mild       retrospective study, Guisado-Vasco et
group, characterised by lower abun-           and do not affect patient prognosis,        al. evaluated the value of a quantitative
dance of Neisseria and Porphyromonas          some may have a relevant impact on          CT (QCT) index in identifying the ex-
and a higher abundance of Veillonella,        disease outcome and patient quality of      tension of lung disease in pSS patients
differed significantly from non-SS            life (14). In recent years, considerable    with ILD (19). There was a statistically
group, thus suggesting that hyposaliva-       effort was directed to the investigation    significant difference in QCT index
tion alone is not necessarily the cause       of biomarkers which may identify spe-       distribution between pSS patients with
of dysbiosis in pSS (11). Finally, xeros-     cific disease phenotypes (15).              and without ILD. Moreover, higher
tomia in pSS patients may be associ-          Clinical manifestations related to lung     scores identified patients with more ex-
ated with higher risk of periodontal dis-     involvement in pSS patients are varied      tensive parenchymal involvement (19).
ease (PD), including higher prevalence        and initial symptoms are usually non-       Among serologic markers, a retrospec-

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One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

tive analysis of the medical records of     ative prognostic outcome (24). In fact,     sion was observed during follow-up, in-
a wide cohort of Korean pSS patients        these patients usually experience high-     cluding all pSS patients with anti-CCP
without features of antineutrophil cy-      er level of disease activity and onset or   antibodies, and immunosuppressive
toplasmic antibody (ANCA) vasculitis        worsening of disease activity in the pe-    agents, including hydroxychloroquine,
demonstrated that positivity of ANCA-       ripheral nervous system (PNS) domain        methotrexate and rituximab, showed a
myeloperoxidase at baseline is predic-      is significantly associated with higher     similar good efficacy in reducing pain
tive of ILD development in pSS (20).        level of disease activity after long-       and joint inflammation (30). A recent
Among the wide spectrum of systemic         term follow-up (25). Finally, it exerts     systematic review and meta-analysis
extra-glandular manifestations, renal       a negative impact on patient quality        of ten studies involving 1322 pSS pa-
involvement may significantly influ-        of life due to its disabling symptoms,      tients demonstrated that anti-CCP anti-
ence disease course due to its insidious    often requiring immunosuppressive           bodies are associated with a significant
clinical appearance which may delay         therapies (26). Neurological mani-          four-fold higher risk of arthritis in pSS
the diagnosis. In a recent analysis of      festations account for 10% to 60% of        patients and with development of RA
20 pSS patients, tubulointerstitial ne-     cases, being the PNS involvement the        (31).
phritis (TIN) occurred near or prior to     most frequently reported (24). Sensory      It is well known that pSS is frequently
the onset of sicca symptoms manifest-       or pure sensory neuropathies, in par-       associated with organ-specific auto-
ing as distal renal tubular acidosis with   ticular painful small-fibre neuropathy      immune disorders, in particular with
hypokalaemia (21). On the opposite,         (SFN) and dorsal root ganglionopathy,       autoimmune thyroid disease. In or-
glomerular involvement, mainly mem-         have been frequently described as pe-       der to evaluate if autoimmune thyroid
branoproliferative glomerulonephritis       culiar features (24). These patients are    disease represents a distinct nosologic
(GN) with cryoglobulinaemia, mani-          characterised by a distinct clinical and    condition differing from pSS, Anaya
fested years after disease onset with       serologic profile as highlighted in a       et al. performed a retrospective analy-
chronic kidney disease, haematuria or       recent cross-sectional study involving      sis of about 300 pSS patients compar-
nephrotic proteinuria (21). Moreover,       pSS patients with biopsy-proven SFN.        ing clinical and serologic features of
TIN was characterised by indolent           Patients with SFN were mainly male          patients with pSS alone and patients
course not responding to immunosup-         and had decreased frequency of anti-        with pSS and Hashimoto’s thyroiditis
pressive therapy while GN showed a          SSA/Ro 52/60 antibodies and of rheu-        (HT) (32). Primary SS with HT were
favourable response to immunosup-           matoid factor (27). Similarly, in a wide    characterised by higher prevalence of
pressive agents, including rituximab,       prospective Korean cohort analysis,         lymphadenopathy and urticaria while
mycophenolate mofetil and cyclophos-        anti-SSA/Ro-negative patients were          anti-Ro/SSA antibodies were more
phamide (21). Researchers investigated      characterised by higher prevalence of       frequent in the pSS group, suggest-
biomarkers useful in identifying renal      PNS at ESSDAI domain in comparison          ing that, although SS and autoimmune
disease in pSS. In a wide pSS cohort,       to anti-SSA/Ro-positive (28).               thyroid disease share common physi-
renal involvement was associated with       Besides the glandular disease, joint in-    opathologic mechanisms as part of the
higher levels of creatinine, cystatin C,    volvement represents one of the most        autoimmune background, they should
and alpha-1-microglobulin (α1-MG)           frequent disease manifestations. It has     be considered two different entities.
(22). Similarly, in a large cross-sec-      been reported in 20% up to 60% of           In the recent years, convincing evi-
tional study of more than four hun-         pSS patients, and about one third pre-      dence suggested that patients with sys-
dred Chinese pSS patients, histologi-       sents synovitis resembling rheumatoid       temic rheumatic diseases, in particular
cal positivity of salivary gland biopsy,    arthritis (RA) (29). In order to charac-    pSS, may have an increased risk of coe-
reduced C3 levels, hypoalbuminaemia         terise the features and the therapeutic     liac disease (CD). A recent multicentre,
and anaemia were significantly associ-      outcome of pSS-associated arthritis,        case-control, Italian study involving
ated with higher risk of renal involve-     Mirouse et al. performed a retrospec-       more than 1,400 patients with systemic
ment. Interestingly, xerophthalmia and      tive analysis of a French cohort of 57      autoimmune diseases, including pSS,
anti-SSA/Ro52 positivity displayed a        pSS patients with at least one episode      systemic lupus erythematosus (SLE)
negative association (23). This study       of clinical and/or echography detected      and systemic sclerosis, reinforced this
suggests that pSS patients with renal       synovitis (30). Patients with synovitis     hypothesis (33). Primary SS patients
involvement are characterised by a          were characterised by higher frequency      were characterised by significant high-
distinctive clinical profile with higher    of parotid gland swelling, lymph node       er prevalence of CD in comparison to
disease activity, higher prevalence of      enlargement and a significantly higher      a wide general population (6.78% vs.
salivary gland biopsy positivity and el-    ESSDAI score in comparison to pa-           0.64%). Moreover, pSS patients with
evated inflammation, but a lower prev-      tients without synovitis. No difference     CD were younger at autoimmune dis-
alence of xerophthalmia.                    between groups was detected regarding       ease diagnosis in comparison to non-
Neurological involvement represents a       acute phase reactants, rheumatoid fac-      coeliac group, thus suggesting that
relevant clinical challenge in these pa-    tor positivity or detectable anti-cyclic    screening for CD may be considered in
tients due to its heterogeneous presen-     citrullinated peptide (CCP) antibodies.     young pSS patients, especially at dis-
tation, diagnostic complexity and neg-      Of note, no structural erosive progres-     ease diagnosis.

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It is important to consider that concom-      major CV events. The first was charac-      immune checkpoint inhibitors (ICI)s,
itant comorbidities, including infection      terised by close interconnection of tra-    and sicca syndrome is described as a
risk, CV disease and non-lymphoma ne-         ditional CV risk factors to each other      complication of ICI therapy. Recently,
oplastic diseases (in particular, thyroid     and to pSS glandular involvement. The       Warner et al. evaluated 20 patients who
gland cancer), may also influence pSS-        second pattern, including ischaemic         developed sicca syndrome after ICI
related morbidity and mortality (34).         CV events, was closely associated with      treatment (50). The median interval
Indeed, pSS patients are characterised        extra-glandular disease activity, longer    between ICI introduction and symptom
by increased prevalence of subclinical        disease duration and some clinical or       onset was 70 days. Dry mouth, assessed
atherosclerosis and higher risk of both       serological manifestations typical of       by reduction of whole unstimulated sa-
cerebrovascular and CV events in com-         the autoimmune phenotype, including         liva flow, was reported in all patients.
parison to general population (35-37).        purpura, leukopenia, low complement         Acute dry eye developed in 6 patients
Multiple interacting mechanisms have          and cryoglobulinaemia.                      of which 5 had a positive Schirmer test
been associated to the acceleration of        Finally, pSS patients complain a re-        in at least one eye. Only 3 patients had
subclinical atherosclerosis and CV            duced quality of life as result of sys-     positive test for anti-nuclear antibody
damage in these patients. Traditional         temic chronic symptoms, like fatigue,       (ANA) and 2 for rheumatoid factor and
CV risk factors play a relevant role          depression and anxiety, which signifi-      anti-SSA antibodies. Almost all patients
in the contribution to atherosclerotic        cantly affect health-related quality of     underwent labial salivary gland biopsy
damage, as recently highlighted (38).         life (HRQoL). Indeed, HRQoL reduc-          with demonstration of a mild chronic
In particular, hypertension emerged as        tion in pSS is similar to that reported     sialadenitis with focal lymphocytic
a prominent CV risk factor being more         in other systemic rheumatic disorders,      infiltration in the majority of patients.
prevalent in these patients and associ-       as RA and SLE (45). In pSS patients,        Interestingly, inflammatory infiltrate
ated with increased risk of overt CV          impaired HRQoL is associated with           was mainly characterised by predomi-
events (39, 40). In a recent study re-        fatigue, pain, articular involvement,       nance of CD3+ and CD4+ T cells with
cruiting a cohort of 367 pSS patients,        sicca symptoms, pulmonary mani-             paucity of CD20 B cells. In addition to
hypertension, older age and extra-            festations, psychological dysfunction       supportive measures and ICI therapy
glandular involvement were indepen-           and impaired physical function (45).        withdrawn, corticosteroids therapy was
dently correlated with CV events (41).        Patients complain sleep problems, re-       employed in almost all patients.
Secondly, inflammatory mediators and          duced sleep efficiency and daytime          Ramos-Casals et al., in the Immuno
disease-related immune markers coop-          hyper-somnolence (46). In addition,         Cancer International Registry, identi-
erate with traditional CV risk factors        mood and several neuropsychological         fied a total of 26 patients who devel-
in the pathogenesis of atherosclerotic        domains such as cognition difficulties      oped sicca syndrome after treatment
damage (42). In particular, the high-         with attention, focusing, memory and        with ICI (51). These patients were
est CV risk appears to be associated          new learning, are commonly reported         mainly men with a median age at di-
with circulating anti-Ro/SSA and La/          problems in pSS (47). In order to bet-      agnosis of 64 years. Of these, 25 pa-
SSB, as demonstrated in a recent case-        ter characterise factors contributing to    tients developed dry mouth and 17 dry
control study with a median follow-up         fatigue in these patients, Pertovaara et    eyes. Minor salivary gland biopsy was
of 10 years (43). Finally, adjunctive         al. have analysed a cohort of 100 pSS       performed in 15 patients and depicted
features, like disease duration, may          patients and depicted that fatigue was      mild chronic sialadenitis in 8 subjects
further increase CV morbidity in pSS          associated with disease duration and        and focal lymphocytic sialadenitis in
(43). In order to evaluate the interplay      some inflammatory markers (48). Om-         the remaining 7. Immunological mark-
between disease-specific inflammatory           dal et al. hypothesised that, besides in-   ers included positive ANA and anti-Ro/
and autoimmune features, and tradi-           flammation and cellular stress respons-     SSA in the majority of cases. In sum-
tional CV risk factors in influencing          es, pain represents another activator of    mary, ICIs should be included in the
CV risk, an artificial neural network          the sickness response, therefore induc-     list of drugs causing sicca symptoms
analysis has been recently applied to         ing fatigue. In particular, interleukin     but patients developing sicca syndrome
a cohort of 408 pSS patients (44). In-        (IL)-1β signalling in the brain possibly    after therapy introduction display a
terestingly, in the entire cohort, hy-        represents a final common pathway for       specific phenotype different from pSS,
pertension resulted the most prevalent        fatigue. Interleukin-1β has also been       mainly characterised by increased
traditional CV risk factor and patients       implicated in depression, thus explain-     prevalence of males, higher age at di-
presenting with at least one CV event         ing why fatigue and depression are so       agnosis, negative immunologic profile
displayed significant higher prevalence        tightly associated (49).                    and extra-glandular involvement (51).
of hypertension (77%) with respect
to subjects free from CV comorbidity          Sicca syndrome and immune                   Take home messages
(35%). This new data mining computa-          checkpoint inhibitors                       • Over one quarter of patients with pSS
tional analysis allowed to identify two       Rheumatic immune-related adverse            display extra-glandular manifestations
different patterns of distribution in CV      events are often reported in patients       not included among ESSDAI domains
risk factors, pSS-related features and        with cancer receiving therapy with          (14).

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•Alpha-1-microglobulin (α1-MG) may          was similar in all the pSS biopsies, al-    in associated autoimmune conditions
prove a useful biomarker for renal in-      though significantly higher than in con-    (17.3%) in patients with DLBCL
volvement in pSS (21, 22).                  trols. Finally, TSLP expression by sali-    treated with R-CHOP/CHOP-like regi-
• Patients with peripheral nervous sys-     vary epithelium declined along with         mens, compared to the general popula-
tem involvement usually display more        the progression of B-cell lymphopro-        tion (3-10%) (59). Furthermore, NHL
active systemic disease and lower           liferation, the B-cells themselves in-      associated with those with autoimmune
prevalence of sicca features (24, 28).      creasingly becoming TSLP-positive. A        conditions driven by B-cell responses,
• PSS-associated arthritis is usually       pathogenetic role of TSLP in pSS-as-        mainly women with pSS, SLE and RA,
non-erosive and subjects with positive      sociated lymphoproliferation was then       had a worse survival (59).
anti-CCP autoantibodies are at higher       supported (55).                             Paediatric pSS is a relevant subset of
risk of developing RA (30, 31).             The role of TREX1 on the risk of pSS        pSS. Tesher et al. presented two cases
• Other autoimmune diseases, such as        and pSS-related lymphoma was ex-            of paediatric pSS and reviewed the
autoimmune thyroiditis and coeliac          plored by Nezos et al. The expression       literature. Importantly, one of the two
disease are more prevalent in pSS sub-      of three single nucleotide polymor-         patients was successfully treated with
jects compared to the general popula-       phisms of the TREX1 gene (rs11797,          rituximab and hydroxychloroquine,
tion (32, 33).                              rs3135941 and rs3135945) and of IFN-        and did not need chemotherapy. The
• Immune-checkpoint inhibitors can in-      I genes was evaluated in patients with      clinical differential diagnosis between
duce sicca syndrome with features of        pSS, pSS-associated lymphoma and            non-malignant parotitis and parotid
sialadenitis, though clinically, serolog-   healthy controls. Patients carrying the     NHL in pSS was also stressed by the
ically and pathologically distinct from     rs11797 AA genotype had increased           Authors (60).
SS (50, 51).                                type I IFN-related gene expression in       A useful review by Talotta et al. inte-
                                            minor salivary glands. Significantly        grates the role of dysbiosis and chronic
Lymphoma in pSS: what is new?               decreased prevalence of the rs11797         infections with the epigenetic control
Novel biomarkers                            A minor allele was detected in pSS pa-      of gene expression in pSS patients,
Low miR200b-5p levels in minor              tients with non-MALT lymphoma. A            and their possible involvement in B-
salivary glands (MSGs) represent a          genetically related defective type I IFN    cell lymphomagenesis (61). These fac-
proposed novel predictor for the de-        production could represent a potential      tors act by inducing hyperexpression
velopment of lymphoma in pSS. Ka-           mechanism in pSS-related lymphom-           of genes that are mainly involved in
psogeorgou et al. provided additional       agenesis (56).                              the innate and adaptive immune re-
data supporting low miR200b-5p as an                                                    sponses and oncogenesis. Major ones
independent predictor, since the pre-       Pathogenetic issues                         are the interferon-I (IFN-I) and IFN-
dicting power resulted independent          Gorodetskiy et al. examined the clonal      II signature (62) and IFN regulatory
from the degree of MSGs infiltration        relationship between low- and high-         factor 5, mediating both viral latency
and focus score (52-54). Another novel      grade NHLs in pSS. Data from 6 pSS          and B-cell transformation (63, 64).
biomarker of lymphoproliferation in         patients who had developed MZL and          Microbial agents may also promote
pSS indicated by Gandolfo et al. is         synchronous or metachronous DLBC            the activation of proinflammatory and
thymic stromal lymphopoietin (TSLP).        were analysed, identifying immuno-          survival pathways in the salivary gland
Significantly higher TSLP serum levels      globulin heavy chain gene rearrange-        epithelium and lymphocytes, through
were found in pSS patients and, impor-      ments by means of multiplex PCR             the alteration of the epigenetic back-
tantly, they increased from fully benign    and GeneScan fragment analysis. In          ground, giving to B and T lymphocytes
infiltrates to parotid myoephitelial si-    5/6 cases, low and high-grade tumour        an activated or transformed phenotype.
aladenitis (MESA) and finally to NHL.       pairs showed identical clonal pat-          The role of transposable integrated ret-
Of note, TSLP was also studied in pSS       terns, despite being located in different   roviral elements in B-cell deregulation
pathologic tissues, again stratified from   sites. Then, the concept that DLBCL         was also commented (65). The review
fully benign, MESA and NHL, and in          frequently results from low-grade           by Nakamura et al. is of value to con-
controls. Both RT-PCR immunohis-            lymphoma progression in pSS is sup-         sider pSS-related lymphomagenesis in
tochemistry and immunofluorescence          ported (57). Xian et al. investigated       the light of marginal zone/MALT lym-
were used. A significant increase in the    the association between B-cell growth       phomagenesis in general, the Authors
percentage of TSLP-positive B-cells         factors and pSS-related autoantibod-        focusing on the latter (66).
along with the worsening of B-cell          ies in patients with NHL, analysing
lymphoproliferation was evidenced,          BAFF, anti-SSA/Ro, IL-14, and tissue        Lymphoma risk and lymphoma
maximal in NHL. Furthermore, induc-         specific autoantibodies (TSA) includ-       diagnosis
ible TSLP (the long isoform of TSLP         ing SP1, CA6 and PSP (58). However,         A novel methodology to develop lym-
mRNA) was detected only in higher           also a high number of pSS-unrelated         phoma prediction in pSS patients, giv-
grades of B-cell lymphoproliferation        control NHLs patients were positive         ing emphasis also on a quality control
(MESA and NHL), whereas the short           for pSS-associated antibodies in this       pipeline for clinical data, was presented
constitutive isoform of TSLP mRNA           study. Mörth et al. detected an increase    by Pezoulas et al. (67, 68). Such meth-

S-14                                                                                     Clinical and Experimental Rheumatology 2020
One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

odology is represented by a first rule-       Take home messages                          SGUS-guided CNB was targeted to the
based, binary supervised learning mod-        • Thymic      stromal     lymphopoietin     most suspicious sonographic detected
el. A boosted decision tree model was         (TSLP) expression in salivary glands        glandular area, allowing the sampling
used to identify prominent features with      correlates with the degree of lym-          of parotid and submandibular glandu-
increased importance for lymphoma de-         phoproliferation and is highest in non-     lar tissues with different sonographic
velopment in pSS. The results showed          Hodgkin’s lymphoma (55).                    patterns. A targeted sonographic ap-
an average accuracy 87.1% with an av-         • Diffuse large B-cell lymphoma may         proach improves the ability of SGUS-
erage area under the curve (AUC) score        represent a progression from low-grade      guided CNB for differential diagnosis,
88%. This model supported the impor-          B-cell lymphoma (57, 58).                   and also sarcoidosis and IgG4-related
tance of C4, rheumatoid factor and lym-       • Dysbiosis and chronic infections may      disease were diagnosed. Importantly,
phadenopathy as prominent lymphoma            be able to promote B-cell proliferation     the observation of fewer long-term and
predictors, along with major salivary         and transformation by epigenetic mod-       transient complications in SGUS-guid-
gland enlargement (67, 68).                   ulation of cell survival pathways (61).     ed CNB in comparison to open surgical
Prediction of lymphoma in pSS was             • A composite prediction score for lym-     biopsy, as reported, could have a high
reviewed by several Authors. When             phoma development is currently under        impact on the patient’s acceptance of
analysing classic and novel predictive        investigation (72, 73).                     the proposed biopsy (76). Last-gener-
markers of NHL, Kapsogeorgou et al.                                                       ation ultra-high-resolution ultrasound
highlighted the relevance of recent           Salivary gland ultrasonograpy               (UHFUS) transducers, which can pro-
multifactorial predicting models, and         (SGUS)-assisted developments:               duce frequencies up to 70 MHz and
of novel analytical approaches in gen-        salivary gland biopsy, image                achieve tissue resolution up to 30μm,
eral. These are based on machine learn-       segmentation, glandular damage              offer new possibilities to visualise labi-
ing and on big data analyses, to permit       and evaluation of disease activity          al salivary glands and to guide diagnos-
harmonisation of patients and the crea-       Ultrasound-guided salivary gland            tic biopsy procedure. Recently, Baldini
tion of universal algorithms (69).            biopsy                                      et al. demonstrated that the mean labial
Nocturne et al. highlighted the need of       Salivary gland ultrasound-guided core       glandular surface area obtained by the
an international consensus on salivary        needle biopsy (SGUS-guided CNB) is          high-resolution ultrasound guided pro-
gland histopathology in pSS and on            an established, effective and safe pro-     cedure was significantly higher than the
the immunohistological definition of          cedure currently applied in the diag-       area obtained by traditional biopsy pro-
germinal centres (70). The relevance          nosis of salivary gland masses, mainly      cedure. This procedure could facilitate
of histopathology was also stressed by        epithelial tumours. SGUS-guided CNB         the assessment of the focus score (77).
Delli et al. (71). The pathogenetic role      might have a role also in the manage-
of CD21 low B cells and SCOLYSS               ment of the frequent pSS patients with      The application of image-segmentation
were also reported. SCOLYSS is a              salivary gland enlargement, that could      and of artificial intelligence to SGUS
recently proposed composite score to          underlie an already established lym-        The significant intra- and inter-rater
predict the risk of lymphoma in pSS,          phoma or be a pre-lymphomatous pro-         disagreement in SGUS scoring is cur-
and is currently under investigation. It      cess. Recently, two pilot studies have      rently considered as a major obsta-
was reported that seven simple varia-         highlighted the role of SGUS-guided         cle for the acceptance of SGUS as a
bles, easy to be evaluated will be used:      CNB as a safe and useful technique          classification and management tool
the variables to build SCOLYSS have           for evaluation of suspected salivary        for pSS. As an alternative to human-
then been established a priori (70).          gland lymphoma in pSS patients. In          dependent assessment of sonographic
Goules et al. reviewed the more recent-       a retrospective study in patients with      lesions from SGUS, it is possible to
ly proposed molecular and genetic bio-        suspected parotid lymphoma, Baer et         employ computer algorithms for tex-
markers for pSS-associated lymphoma           al. described that SGUS-guided CNB          ture analysis and use the extracted fea-
prediction (72), and Retamozo et al.          provided sufficient pathologic mate-        tures to develop artificial intelligence
emphasised the importance of studying         rial to differentiate a range of salivary   (AI) algorithms to assist human ex-
synergistic models of lymphoma risk           gland pathologic findings, from nor-        perts in SGUS scorings (78). Recently,
(73).                                         mal salivary gland tissue to a diffuse      Vukicevic et al. in a multi-centre col-
Regarding the diagnosis of NHL in pSS,        lymphocytic infiltration, representing      laboration in the HarmonicSS project,
Keraen et al. retrospectively examined        either benign lymphoepithelial sialad-      tested various radiomics-based AI
the usefulness of 18F-FDG-PET-CT.             enitis or MALT lymphoma (75). The           algorithms for SGUS scoring in pSS
The Authors reported three PET pat-           accuracy of SGUS-guided CNB for the         patients, identifying AI algorithms that
terns associated with the presence of         diagnosis of salivary gland lymphoma        performed as human experts and could
lymphoma in pSS with moderate to              has been recently confirmed by Zabotti      be therefore useful to assist clinicians
high systemic disease activity. PET-TC        et al. in a prospective cohort of pSS       in SGUS (79). The diagnostic perfor-
was found useful also in guiding the          patients with parotid or submandibular      mance of a deep learning system for
histologic diagnostic procedure and in        gland enlargement (76). Furthermore,        the detection of pSS by SGUS in 100
monitoring response to treatment (74).        differently from the previous study,        patients with a confirmed diagnosis of

Clinical and Experimental Rheumatology 2020                                                                                    S-15
One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

pSS according to classification criteria    rogates” of pathologic MALT involve-          cytokine secretion via inhibition of au-
was studied (80). The authors conclud-      ment, clinical (e.g. parotid swelling         tophagy (87).
ed that the deep learning system had a      and cryoglobulinaemic vasculitis) and         Local cyclosporin A (CyA) is rou-
high diagnostic ability for pSS by the      laboratory (e.g. low C4, cryoglobuli-         tinely used to treat xerophthalmia and
use of SGUS images (80). The increase       naemia, rheumatoid factor/idiotypes,          corneal damage in SS. Despite hav-
in case collection and sonographic im-      free immunoglobulin light chains, se-         ing demonstrated beneficial effects, its
ages is needed.                             rum beta 2 microglobulin). The pres-          use is limited by the poor tolerability
                                            ence of surrogates was introduced to          and bioavailability due to the scarce
Salivary gland damage                       allow some evaluation also when tis-          hydrosolubility of the molecule. Sci-
The role of the SGUS in monitoring          sue biopsy is not available or cannot be      entific efforts are therefore concen-
the history of pSS in a non-invasive        repeated, for any reason.                     trated towards an improvement of the
manner, the response to treatment, in                                                     pharmacokinetics properties of topical
predicting the outcomes and in detect-      Take home messages                            CyA. A pooled analysis of the results
ing lymphoma, although promising, is        • Salivary gland ultrasound-guided            of two phase III randomised clinical
still not well delineated (81). The SG      core needle biopsy is a safe and useful       trials that tested the effect of a cationic
abnormalities due to pSS are believed       technique for evaluation of suspected         emulsion of CyA on dry eye has been
to progress slowly over time, resulting     salivary gland lymphoma in pSS pa-            recently performed with involvement
in changes in SGUS findings. Based on       tients (75, 76).                              of 734 patients of which about 1/3 had
the present knowledge, SGUS could           • Application of salivary gland ultra-        SS-related sicca syndrome. The results
help to identify active inflammatory le-    sonography may have importance in             showed a significant effect on signs
sions, namely the hypo-anechoic areas,      the evaluation of disease activity for        and symptoms in the group of pSS pa-
and the damage-related lesions, the hy-     the future (84, 85).                          tients with severe dry eye, but not in
perechoic bands (82). In a recent study,                                                  the overall pSS population, with a tol-
the hyperechoic bands were identified       What is novel in the                          erability profile equivalent to standard
as the sonographic lesions mainly asso-     treatment of pSS                              CyA formulations (88). Recently, as
ciated with SG impairment, objectively      It is well known that the majority of pSS     an emulsion formulation tends to floc-
evaluated by reduced salivary flow          patients only manifest dry eye and dry        culate and sediment over time, a more
rate, in pSS patients with a disease du-    mouth-related symptoms, which, how-           stable and bioavailable nanoemulsion
ration ≥5 years (83).                       ever, may have a severe impact on qual-       has been tested in a clinical trial in
                                            ity of life. Current treatment is based       South Korea with promising results. In
Evaluation of pSS activity                  on local tear and saliva substitutes,         fact, it improved both symptoms and
It was recently highlighted that the        immunosuppressants and systemic               signs of dry eye with an equivalent ef-
quantification of inflammation and          secretagogues, though these strategies        ficacy compared to the approved for-
lymphoproliferation within the sali-        are frequently ineffective and scarcely       mulation of CyA. However, the effect
vary MALT can be a novel tool to            tolerated. For these reasons, a strong        of the nanoemulsion was evident at an
evaluate pSS disease activity (84, 85),     scientific effort in this field is directed   earlier time-point, presumably due to
also related to the lymphoma risk.          towards new potential approaches to           its higher bioavailability (89).
Despite being the pathobiologic and         treat sicca syndrome. Recently, new in-       Other immunosuppressants are un-
phenotypic essence of pSS, glandular        teresting data have been published from       dergoing investigation for the local
inflammation and lymphoproliferation        in vitro, animal studies, clinical trials     treatment of dry eye in pSS, such as
contributes limitedly to ESSDAI. Fur-       and observational studies.                    sirolimus, which exerts its activity by
thermore, ESSDAI is low in about 30%        Although there is no strong evidence          inhibiting the signal transduction of in-
of pSS who develop NHL and does not         from clinical trials in support of the ef-    terleukin (IL)-2 and, therefore, the ac-
appear as a good predictor (86). In         fect of conventional disease-modifying        tivation of B and T cells, essential play-
a cohort of 30 pSS cases with NHL,          antirheumatic drugs (DMARD) on tear           ers in the pathogenesis of the disease.
persistent SG swelling and cryoglob-        and saliva production, nor on the at-         Its potency is higher compared to CyA
ulinaemia were the major predictors of      tenuation of sicca symptoms, evidence         but similar in terms of water solubility,
NHL in pSS. They mirror B-cell clones       showing efficacy in animal models is          limiting its capability of penetrating the
employing peculiar rheumatoid-factor-       growing. Lee et al. demonstrated that         tear film barrier. Nonetheless, subcon-
related immunoglobulin genes, prone         NOD mice, a mouse model of diabetes           junctival injection of sirolimus follow-
to malignant transformation. A recent       that spontaneously develop sialoadeni-        ing microencapsulation in NOD mice
subproject within the HarmonicSS pro-       tis resembling SS, treated with chloro-       showed a dose-dependent improve-
ject (https://www.harmonicss.eu) is the     quine in the early stages of the disease      ment of tear secretion and corneal dam-
creation of a new composite activity        are characterised by improvement of           age compared to controls, suggesting a
index for pSS, based on histopathol-        tear secretion, corneal damage, lacri-        potential benefit in pSS patients (90).
ogy as the golden standard whenever         mal and salivary gland inflammatory           The mTOR signalling pathway regu-
possible, but also with additional “sur-    cell infiltration and pro-inflammatory        lated by sirolimus is also inhibited by

S-16                                                                                       Clinical and Experimental Rheumatology 2020
One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

metformin, via the activation of AMP-         have the great advantage of being ac-       complicate with the development of
activated protein kinase (AMPK). It           cessible and easy to extract. Their abil-   abrasions, ulcerations and occasionally
is known that the inhibition of mTOR          ity to modulate the immune response         corneal perforations, which require a
in T cells promotes their preferential        is now well established, however more       more aggressive treatment. Shafer et
differentiation towards a regulatory          data are necessary to characterise their    al. have attempted the use of cryopre-
(Treg) phenotype. Similarly, AMPK             behaviour in vivo. In a rabbit model of     served amniotic membrane, locally ap-
activation causes inhibition of signal        dacryoadenitis, hUCMS were shown            plied on the ocular surface, and showed
transducer and activator of transcrip-        to promote macrophage polarisation          that after few days the symptoms and
tion (STAT)3 which is involved in the         towards an M2 phenotype, therefore          ocular surface damage dramatically
differentiation of Th17 and T follicular      favouring an anti-inflammatory behav-       improved, although the benefit was
helper (Tfh) cells. Based on these data,      iour and ultimately improving damage        short-lasting. Being only a case series,
a study performed on NOD mice treat-          and function of lacrimal glands (96).       it would be interesting to further ex-
ed with metformin showed significant          One of the limitations of the use of cell   plore this therapeutic strategy, which
improvement of saliva secretion and a         therapy is the immunogenicity induced       may exert its effect acting both as a
reduction of salivary glands T cell infil-    by the injection of allogenic cells into    mechanical barrier and as a modulator
tration and pro-inflammatory cytokines        the host. Despite hUCMS should not          of inflammation (100).
levels, along with a promotion of T cell      induce immunogenicity, their survival       As previously mentioned, pSS may
differentiation towards a regulatory          in vivo is relatively short. Multiple       be a systemic disease and almost all
(Treg) phenotype (91). A similar effect       methods have been attempted in order        patients complain of systemic symp-
on Th17, Treg and Breg cells and on           to overcome these limitations, includ-      toms such as fatigue. Several thera-
pro-inflammatory cytokines in NOD             ing administration of an extract, rather    peutic strategies have been attempted
mice salivary glands was observed fol-        than viable cells, with preliminary data    in order to improve fatigue, with very
lowing the administration of rebami-          showing equivalent effects (97). An         scarce outcomes. However, some non-
pide, a gastroprotective agent able to        alternative potential method to modu-       pharmacological strategies may have
enhance prostaglandin synthesis. How-         late immune system activity is through      a potential benefit, such as supervised
ever, the mechanisms underlying this          therapeutic administration of antigens,     exercise and non-invasive vagus nerve
effect require further research (92).         resembling a vaccination response. A        stimulation, which have been demon-
Some data on approaches other than            recent study showed that the adminis-       strated to improve fatigue, cardiores-
systemic secretagogues for the treat-         tration to a murine model of sialoadeni-    piratory fitness and exercise tolerance.
ment of xerostomia have been pub-             tis of transgenic rice seeds expressing     Vagus nerve stimulation was also able
lished and showed an improvement              peptide ligands of the M3 muscarinic        to significantly reduce the secretion of
of patient-reported outcomes (PRO)            receptor engineered in order to re-         pro-inflammatory cytokines by periph-
and salivary secretion using salivary         place amino acid residues at the sites      eral blood mononuclear cells (PBMC)
stimulants such as malic acid lozenges        of interaction with the T cell receptor     (101, 102), suggesting a potential wid-
and citric acid solution, with a stronger     (TCR), is able to modulate the immune       er application of the technique.
effect by the former. Additionally, in a      response by increasing salivary flow,       In patients with systemic involve-
group of patients – 1/3 diagnosed with        reducing glandular inflammation, pro-       ment, treatment strategies are mostly
SS and the other with xerostomia due to       inflammatory cytokine secretion in the      based on expert opinion and the use
other causes – who underwent salivary         gland and balance between Th17 and          of pharmacological approach is mutu-
gland irrigation procedures through the       Treg cells. These aspects deserve how-      ated from the evidence in other auto-
retrograde injection of saline into the       ever further investigation (98).            immune and inflammatory diseases.
four major salivary gland, a significant      In patients with severe, long-lasting       For this reason, there is great interest
proportion experienced an increase of         sicca syndrome, complications of the        in building scientific evidence in sup-
unstimulated salivary flow (93). Addi-        lack of saliva and tears are frequent.      port of the use of immunomodulatory
tionally, two meta-analyses performed         One of the most concerning aspects is       and immunosuppressive therapies. Hy-
on pharmacological treatment of xeros-        the increased frequency of caries. One      droxychloroquine (HCQ), methotrex-
tomia in pSS confirmed a positive out-        of the objectives of sialogogues pre-       ate (MTX) and leflunomide (LEF) are
come for interferon-α, cevimeline and         scription, beyond mitigating the symp-      commonly used in patients with mild
pilocarpine (94, 95).                         toms, is the preservation of oral and oc-   systemic disease, especially with ar-
In recent years, potential applications       ular health. However, unlike the results    ticular involvement, but there is very
of cell and antigen therapy for the           on animal models and some recom-            little evidence on their efficacy in SS.
treatment of SS have been extensively         mendations, a recent study showed no        Interestingly, there is a rationale sup-
investigated and data are progressively       effect on the rate of caries development    porting the combination of HCQ and
accumulating. Human umbilical cord            in patients treated with pilocarpine        LEF. In fact, the pharmacological ef-
mesenchymal stem cells (hUCMS) are            compared to controls (99). Similarly,       fect of LEF is mainly directed towards
multipotent cells extracted from the          dry eye can sometimes be refractive to      the inhibition of T cell response, while
Wharton jelly of umbilical cord and           all the treatments and may sometimes        HCQ mainly affects antigen presenta-

Clinical and Experimental Rheumatology 2020                                                                                  S-17
One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

tion and B cell response. An additive         phosphatidylinositol 3-kinase (PI3Kδ)      of antigen-driven and BAFF-mediated
effect of the two medications has been        as demonstrated by the increased con-      B cell hyperactivation in the evolution
demonstrated in vitro in terms of pro-        centration of downstream peptides in       of lymphoma in pSS (70, 117, 118).
inflammatory cytokine secretion, T and        biopsy samples. Thus, Nayar et al. have    Rituximab monotherapy may be in-
B cell proliferation. A clinical trial has    demonstrated that treatment of a murine    sufficient to deplete the B-cells in the
also been carried out, though data are        model of SS with the PI3Kδ-inhibitor       salivary gland tissue, the resistance of
not yet available (103). Albeit HCQ is        eletalisib, actually used for B-cell ma-   B-cells to rituximab being due to the
a very well tolerated medication, its         lignancies, significantly mitigates pro-   concomitant hyperexpression of BAFF
widespread use warrants careful atten-        inflammatory cytokine and chemokine        in this microenvironment (119).
tion on the potential adverse events. A       secretion, prevents the formation of       Treatment with belimumab, an anti-
recent case-control study suggested a         GCs and improves salivary function         BAFF monoclonal antibody registered
potential association between the use         (110).                                     for the treatment of SLE (120), was em-
of HCQ in pSS and SLE patients and                                                       ployed in the BELISS trial in pSS with
higher prevalence of non-melanoma             New advances in the treatment              encouraging clinical results, including
skin cancer. However, these data need         of lymphoma                                pSS with parotid swelling. Novel treat-
to be confirmed (104).                        Lymphoma development is the main           ment strategies for pSS-related lym-
Numerous clinical trials have been car-       complication decreasing patient sur-       phoproliferation then imply the com-
ried out and others are currently on-         vival in pSS. Low grade B-cell NHL         bination of direct B-cell-depleting and
going on the potential effect of target       of MALT is the largely overrepresented     anti-BAFF agents (116).
therapy for more severe disease mani-         histotype, followed by DLBCL, which        Very long-term remission of a patient
festations. Although some molecules,          may also derive from MALT (15, 111).       with pSS, parotid NHL of MALT,
such as rituximab (RTX), are com-             Treatment decisions for pSS-associated     and cryoglobulinaemic vasculitis was
monly used, little evidence is available      NHL must be case tailored. Treatment       achieved with a sequential treatment
and the results from the trials to date are   of indolent MALT NHL, much more            with belimumab shortly followed by
mostly inconclusive (105). Nonethe-           frequent in pSS, may range widely,         rituximab, while rituximab alone and
less, some interesting studies recently       from a “watch and wait” approach to        belimumab alone, given previously,
explored the effect of the blockade of        cytotoxic therapies, low dose radio-       were both ineffective (113). At present,
various pathways. A small open label          therapy or surgical excision. Chemo-       a double-blind, randomised, placebo-
study has demonstrated a significant          therapy or chemoimmunotherapy may          controlled trial (NCT02631538) is
reduction of median ESSDAI score,             also be used, with a combination of        testing belimumab/rituximab coadmin-
most evident in the articular and glan-       rituximab with either alkylating agents    istration (where belimumab is started
dular domains, following treatment            (cyclophosphamide/chlorambucil), pu-       earlier) in comparison to belimumab
with abatacept (106). Another study           rine analogs (fludarabine, cladribine),    monotherapy in pSS.
demonstrated minimal beneficial ef-           or bendamustine. Conversely, the R-        Another encouraging approach under
fect of ianalumab, a B-cell activating        CHOP regimen (rituximab, cyclophos-        investigation is the use of ianalumab
factor (BAFF) receptor blocker, on            phamide, doxorubicin, vincristine and      (VAY736), an anti-BAFF receptor
fatigue and circulating B-cell levels         prednisone) is often employed in ag-       monoclonal antibody (NCT02149420,
(107). Very interestingly, Combier et         gressive NHL (112).                        NCT 02962895), with double anti-
al. have shown that the development of        However, the major recent novelties        BAFF and direct B-cell depleting prop-
anti-RTX antibodies in connective tis-        implicate biological agents for the        erties. Ianalumab eliminates BAFF-R-
sue diseases is more frequent compared        treatment B-cell lymphoproliferative       positive mature and immature B cells
to RA and patients developing infusion        disorders in pSS that do not require       via antibody-dependent cytotoxicity
reaction due to this phenomenon can be        aggressive approaches. Although bio-       (ADCC) and induces B-cell apoptosis
effectively treated with ofatumumab,          logics are now being investigated for      by blocking BAFF/BAFF-R interac-
another CD20 blocker (108).                   the treatment of pSS as a whole, their     tion (107). Epratuzumab, an anti CD22
In addition, some new pathways are at-        specific role in targeting the pSS sub-    monoclonal antibody, showed some
tracting interest as potential targets in     set with heavier B-cell proliferation      positive results in an older, small phase
pSS. In NOD mice, blockade of CD40            deserves attention. Biologics might be     I/II open-label study in pSS, and recent
ligand was effective in abolishing the        employed in borderline cases where the     post hoc analyses of the EMBODY tri-
formation of germinal centres (GC) in         diagnosis of a definite B-cell malignan-   als showed improvement in disease ac-
salivary glands. CD40-CD40L pathway,          cy is difficult, or in prelymphomatous     tivity in patients with SLE and associ-
in fact, has a crucial role in the co-stim-   conditions in pSS, mainly cryoglobuli-     ated SS, with a decrease in B-cells and
ulation of T and B cells and is strongly      naemic vasculitis with type II mixed       IgM levels (121).
involved in isotype switching and GC          cryoglobulinaemia, and persistent pa-      Other Authors recently focused on
formation (109). Germinal centres in          rotid swelling with heavy underlying       T-cell proliferation, T-cell related cy-
SS salivary gland also show a markedly        MALT lesions (105, 113-116). Recent        tokines and B-cell/T-cell co-stimulation
increased activity of the δ isoform of        studies focused on the fundamental role    pathways in systemic and local MALT

S-18                                                                                      Clinical and Experimental Rheumatology 2020
One year in review 2020: Sjögren’s syndrome / V. Manfrè et al.

inflammation, especially in the ectopic       Take home messages                                  8. BEN-ELI H, AFRAMIAN DJ, BEN-CHETRIT
                                                                                                     E et al.: Shared medical and environmental
germinal centres (122-124). A recent          • New formulations of topical cyclo-
                                                                                                     risk factors in Dry Eye syndrome, Sjögren’s
randomised, double-blind, placebo-            sporine A and sirolimus for dry eye                    Syndrome, and B-Cell Non-Hodgkin Lym-
controlled Phase 3 Study, assessed the        treatment may prove superior in terms                  phoma: A case-control study. J Immunol Res
efficacy and safety of abatacept, which       of bioavailability and efficacy (88, 89).              2019; 2019: 9060842.
                                                                                                  9. KARAKUS S, BAER AN, AKPEK EK: Clini-
blocks the CD28:CD80/CD86 T cell              • Metformin, interferon-a, cevimeline                  cal correlations of novel autoantibodies in
co-stimulation in pSS. Although IgG           and pilocarpine may be effective in im-                patients with dry eye. J Immunol Res 2019;
and RF levels decreased, a significant        proving salivary and tear secretion (91,               2019: 7935451.
improvement in ESSDAI and salivary            94, 95).                                           10. BERMAN N, VIVINO F, BAKER J, DUNHAM
                                                                                                     J, PINTO A: Risk factors for caries develop-
or lacrimal gland function was absent         • Human umbilical cord mesenchymal                     ment in primary Sjögren’s syndrome. Oral
(125).                                        stem cells extracts are able to modulate               Surg Oral Med Oral Pathol Oral Radiol
Targeting the CD40/CD40L pathway              the inflammatory response in murine                    2019; 128: 117-122.
represents another option under study         models of SS, without being immuno-                11. RUSTHEN S, KRISTOFFERSEN AK, YOUNG
                                                                                                     A et al.: Dysbiotic salivary microbiota in
(109, 126). The safety and efficacy of        genic (96, 97).                                        dry mouth and primary Sjögren’s syndrome
a monoclonal antibody against CD40            • Recent reports suggest abatacept,                    patients. PLoS One 2019; 14: e021831.
(iscalimab/CFZ533) in pSS patients            ianalumab and ofatumumab may be ef-                12. LIN CY, TSENG CF, LIU JM et al.: Associa-
was assessed in a phase II clinical           fective for the treatment of more severe               tion between periodontal disease and sub-
                                                                                                     sequent Sjögren’s syndrome: A nationwide
trial (NCT02291029) with encour-              clinical manifestations (105, 106, 107,                population-based cohort study. Int J Envi-
aging results. Another double-blind,          111).                                                  ron Res Public Health 2019; 16: 771.
randomised, placebo-controlled trial          • Treatment of pSS-associated lym-                 13. MAARSE F, JAGER DHJ, KORFAGE A et al.:
                                                                                                     Sjögren’s syndrome is not a risk factor for
(NCT03905525) is ongoing. Fur-                phoma needs to be tailored on the in-
                                                                                                     periodontal disease: a systematic review.
thermore, a randomised double-blind           dividual cases. Multiple clinical trials               Clin Exp Rheumatol 2019; 37 (Suppl. 118):
placebo-controlled study exploring            are currently being carried out testing                S225-33.
the efficacy and safety of VIB4920            the efficacy of different agents directed          14. RETAMOZO S, ACAR-DENIZLI N, RASMUS-
                                                                                                     SEN A et al.: Systemic manifestations of
is ongoing in pSS (NCT04129164),              towards B-cells and T-cells (112, 116).                primary Sjögren’s syndrome out of the ES-
VIB4920 being a fusion protein de-            • Biologics might be employed in pre-                  SDAI classification: prevalence and clinical
signed to bind to CD40L.                      lymphomatous conditions in pSS (e.g.                   relevance in a large international, multi-eth-
Other investigational approaches to           cryoglobulinaemic vasculitis and per-                  nic cohort of patients. Clin Exp Rheumatol
                                                                                                     2019; 37 (Suppl. 118): S97-106.
target B-cell proliferation in pSS im-        sistent parotid swelling with heavy un-            15. VIVINO F, BUNYA VY, MASSARO-GIORDA-
ply the small molecules inhibitors            derlying MALT lesions) (122, 128).                     NO G et al.: Sjogren’s syndrome: An update
(e.g. selective Jak1-, Syk-, BTK- and                                                                on disease pathogenesis, clinical manifes-
PI3k∂-inhibitor), anti-IL7 therapy            References                                             tations and treatment. Clin Immunol 2019;
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the co-stimulation blocker prezalumab             review 2017: primary Sjögren’s syndrome.           syndrome-associated interstitial lung dis-
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122, 123, 127, 128).                                                                             19. GUISADO-VASCO P, SILVA M, DUARTE-
                                                  F et al.: One year in review 2018: Sjögren’s       MILLA MA et al.: Quantitative assessment
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(55, 105) in pSS-related lymphoprolif-            (Suppl. 112): S14-26.                              drome. PloS One 2019; 14: e0224772.
eration will be confirmed, evaluating          5. CAFARO G, CROIA C, ARGYROPOULOU OD             20. LEE SB, CHOI H, KIM MK: Can antineutro-
tezepelumab, i.e. a monoclonal anti-              et al.: One year in review 2019: Sjögren’s         phil cytoplasmic antibody positivity at diag-
                                                  syndrome. Clin Exp Rheumatol 2019; 37              nosis predict the poor outcomes of Sjögren’s
body against TSLP studied in asthma               (Suppl. 118): S3-15.                               syndrome? Rheumatology Int 2020; 7: 1063-
and atopic dermatitis (129), might be          6. ROSAS J, SÁNCHEZ‑PIEDRA C, FERNÁN-                 70.
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                                                  EZ‑TABOADA V, OLIVÉ A et al.: ESSDAI
All these data are preliminary and in-                                                               AN: Renal involvement in primary Sjögren’s
                                                  activity index of the SJÖGRENSER cohort:           syndrome: natural history and treatment out-
tensive research is mandatory before              analysis and comparison with other Europe-         come. Clin Exp Rheumatol 2019; 37 (Suppl.
these molecules can be routinely em-              an cohorts. Rheumatol Int 2019; 39: 991-9.         118): S123-32.
ployed in the clinical practice, though a      7. YOON HJ, CHOI W, YANG JM, JI Y, LEE SS,        22. LUO J, HUO JH, WANG JW, GUO H: High-risk
great amount of new data is expected in           YOON KC: Characteristics of dry eye in pa-         indicators of renal involvement in primary
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the next few years, hopefully leading to          according to the revised 2016 ACR-EULAR            cases. J Immunol Res 2019; 29: 3952392.
breakthroughs in the treatment of pSS             classification criteria. Medicine 2019; 98:    23. LUO J, XU S, LV Y: Clinical features and po-
(122).                                            e14641.                                            tential relevant factors of renal involvement

Clinical and Experimental Rheumatology 2020                                                                                                  S-19
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