AMR in Liver Transplantation: Note on DSA - Presence of DSA associated with increased risk of

AMR in Liver Transplantation:
  Note on DSA
• Presence of DSA associated with increased risk of
  • Chronic rejection
  • Acute rejection with ductopenia
  • Unexplained graft fibrosis
  • Unexplained biliary complications
  • De-novo AIH (non-HLA DSA)

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AMR in Liver Transplantation:
  Note on DSA
• Differences in class I vs class II DSA
  • Liver allograft in simultaneous liver-kidney transplant was thought to
    provide protection from DSA and decrease risk of kidney AMR, but high
    MFI HLA Class II DSA still at risk

• Likely higher MFI cut-off values than in other SOT

• DSA IgG subclass may be important
  • IgG3 strongly associated with graft loss

• DSA found in control patients with no other signs, symptoms,
 or risk factors

AMR in Liver Transplantation: Role of C4d

  In studies that do include the full
  clinicopathologic correlation and clear
  diagnostic terms:
   • Diffuse clearly positive C4d staining in >50% of
     portal tracts (IHC) or sinusoids (IF)
   • Correlates with presence of DSA
   • Correlates with histologic features of AMR
   • Prevalence of reported cases of liver AMR meeting
     criteria of other solid-organ systems: 0.6-3.7%

AMR in Liver Transplantation:
Role of C4d
• Take Home Message
 • Utility of looking for C4d not clearly established
 • No consensus diagnosis of AMR which includes C4d
 • IHC: small portal vessel staining is most specific
 • IF: sinusoidal staining is most specific
 • C4d staining may be seen in other conditions

• Banff 2011 liver group goal for 2013:
 • Better understanding of spectrum of AMR and consensus
  guidelines for C4d interpretation

AMR in Liver Transplantation: Differential
Diagnosis
• Hyperacute rejection
  • Since not often biopsied, histologic features are
    derived from failed explanted allografts and are
    not specific
  • Severe preservation-reperfusion injury
  • Graft ischemia
  • Idiopathic massive hemorrhagic graft necrosis

AMR in Liver Transplantation: Differential
Diagnosis
• Acute antibody mediated rejection
 – Biliary obstruction/technical biliary complications
   • Histologic features overlap:
      – Bile ductular reaction
      – Portal tract neutrophils
      – Cholestasis
 – Preservation-reperfusion injury
 – Acute cellular rejection
 – Infection/Sepsis
   – Cholestasis
   – Acute ascending cholangitis
 – Ischemic injury

Take Home Message: AMR dx
• Due nonspecificity of histologic findings, AMR
 should only be suggested as an etiology of the
 findings
• Definitive diagnosis requires supportive
 clinical/serologic features and exclusion of the
 histologic mimics

AMR in Liver Transplantation: Pitfalls
• The four major diagnostic criteria for AMR dx in renal and
 cardiac allografts have not been adopted for liver
  – Clinical graft dysfunction
  – Compatible histologic features
  – Deposition of C4d
  – Serologic evidence of DSA
• No routine testing for DSA in liver recipients
• C4d immunostaining is less established/less reliable

AMR in Liver Transplantation: Clinical
Aspects
• Prophylaxis
  • For ABO-incompatible grafts (living donor)
    • B-cell directed immunosuppression
      • Rituximab, IVIg, Plasma exchange, Splenectomy
• Treatment
  • B-cell directed immunosuppression
  • Bortezomib: proteasome inhibitor, depletes
   plasma cells→ decreased Ab production

AMR in Intestinal
             Transplantation: Background

Townsend: Sabiston Textbook of Surgery, 18th ed.
Copyright © 2007 Saunders, An Imprint of Elsevier

AMR in Intestinal Transplantation: Clinical
Aspects
  • Extremely limited literature
    • More common in patients undergoing retransplantation
     after failed graft/chronic rejection
    • DSA alone associated with worse outcome

    • DSA with histologic ACR – consider concurrent AMR

    • High PRA is a risk factor for rejection

    • DSA can persist asymptomatically after hyperacute
     rejection resolves

AMR in Intestinal Transplantation: Clinical
Aspects
• Presentation
  • First 2 weeks post-transplant
    • Increased stoma output
    • ACR poorly responsive to standard therapy
    • Persistent mucosal
     ischemia/congestion/hemorrhage
  • Peri- and post-operative syndrome

AMR in Intestinal Transplantation: Clinical
      Aspects
    Peri- and post-operative syndrome
    • Patients with strong crossmatch (T-cell cytotoxicity test) and
      high PRA
       • Segmental graft spasm, cyanosis, petechial hemorrhage
         at reperfusion, lasting 45m
       • Blood-tinged ostomy content within a few hours
       • Ileostomy mucosal congestion for 1-2weeks
       • Endoscopically, graft mucosa dusky with congestion,
         hemorrhagic

Wu et al. Human Pathology, 2004 Nov;35(11):1332-9.

Wu et al. Human Pathology, 2004 Nov;35(11):1332-9.

AMR in Intestinal Transplantation:
Background
   • Hyperacute rejection (hours)
     • Disseminated thrombosis
     • Total ischemic necrosis

   • Associated with presensitization
     • high PRA, DSA

   • Prophylaxis – desensitization
     • IVIg to reduce PRA
     • Protocols not standardized

AMR in Intestinal Transplantation:
Histologic Features
• Capillary endothelial cell enlargement
• Fibrin thrombi
• Vascular congestion
• Hemorrhage
• Neutrophil margination
• Ulceration
• Crypt apoptosis +/-

AMR in Intestinal Transplantation:
Histologic Features
• Features of ACR may be present
  • Crypt apoptosis
  • Crypt epithelial injury
  • Lamina propria mononuclear inflammatory
    infiltrate
  • Ulceration +/-
  • Architectural distortion +/-
• Severe ACR with arteritis

Crypt apoptosis

         Crypt injury & dropout
         Denudation

Remotti et al. Arch Pathol Lab Med, 2012 Jul;136

AMR in Intestinal Transplantation: Role of
C4d
• Nonspecific:
 • C4d + in 36% of intestinal allografts with rejection
 • And in 27% without rejection
 • May be positive in small arterioles of normal intestine

                                Troxell et al. Arch Pathol Lab Med, 2006 130:1489-96.

AMR in Intestinal Transplantation: Role of
  C4d
• Take Home message
 • C4d deposition is nonspecific and may be present independent of
  rejection or absent during hyperacute rejection

AMR in Intestinal Transplantation:
Differential Diagnosis

• Vascular insufficiency/thrombosis
  • Ischemic change

• Preservation/Reperfusion injury
  • First few days post-op, resolves within 1 week
  • Ischemic change, regenerative epithelium, villous
    blunting, minimal inflammation
• Prior biopsy site

AMR in Intestinal Transplantation:
Differential Diagnosis
• Chronic rejection
  • Arteriopathy: Mesenteric, serosal, and submucosal
    vessels
   • Luminal narrowing associated with intimal and medial
     hyperplasia

 • Associated mucosal changes
   • Mucin loss, submucosal fibrosis
   • Also paneth cell loss, neural hyperplasia
   • Nonspecific changes: crypt apoptosis and dropout, villous
     blunting, lamina propria fibrosis

AMR in Intestinal Transplantation: Chronic
rejection
  Does AMR have a role in chronic rejection?
   • Intestinal allograft explants
      • Contracted mesentery with fibrosis and chronic
        arteriopathy

   • Sampling mesenteric vessels for AMR before
     this stage is technically not feasible

AMR in Intestinal Transplantation:
Diagnosis
Take Home message
 • Suspect AMR with DSA, histologic evidence of
  vascular alteration, and early/severe/resistant
  clinical signs of rejection
 • Treating a suspicion since no way to confirm
  AMR dx

AMR in Intestinal Transplantation: Clinical
Aspects
  • Treatment
   • OKT3
   • Steroids
   • Prostaglandin E
  • Prognosis
   • May not be associated with chronic rejection
   • Does not contribute to overall mortality or graft loss

AMR in Pancreas Transplantation
• Pancreas allograft infrequently biopsied due to perceived
  risk
• AMR does occur in pancreas allograft
• Diagnosis requires 3 components (Banff 2011):
  • Histology
                            3/3 = acute AMR
  • C4d IHC                 2/3 = consistent with acute AMR
                            1/3 = clinical exclusion of AMR required
  • DSA
  • (Clinical graft dysfunction not required)

Acute AMR in Pancreas Transplantation
• Histology: evidence of tissue injury
  • Inflammation of interacinar capillaries (capillaritis)
  • Acinar cell damage (swelling, necrosis, apoptosis,
    dropout)
  • Vasculitis
  • Thrombosis

• C4d positive:
  • Diffuse C4d staining of interacinar capillaries (≥ 5% of
   acinar lobule surface

Chronic Active AMR in Pancreas
Transplantation
Diagnosis requires:
 • Combined features of AMR and chronic allograft
   rejection/graft fibrosis
   • Fibrotic expansion of fibrous septae; exocrine atrophy
 • Exclusion of features of acute T-cell-mediated
   rejection
   • Acinar inflammation→damage; also inflammation of
     septae, ducts, venules

Summary
• Liver
  • AMR can be suggested as dx, as histologic features
    overlap with other dx
  • C4d utility not clearly established
  • No consensus diagnostic criteria
• Small bowel
  • Histologic features and clinical syndrome described
  • C4d nonspecific
• Pancreas
  • Consensus dx criteria including histology, C4d IHC, and
    DSA
  • Infrequently biopsied

Summary
• Kidney
  • AMR very significant, acute and chronic forms, C4d done routinely
    (IF preferred)
• Heart
  • About 15% of patients, markedly increased risk of chronic rejection
    and death, C4d very helpful, IHC or IF
• Lung
   • Rare, diagnosis based on clinical graft dysfunction, circulating
     antibodies, absence of cellular rejection, non-specific C4d staining
     common, however strong endothelial staining reported

References
• Hübscher SG. Antibody-mediated rejection in the liver allograft. Curr Opin Organ Transplant. 2012
    Jun;17(3):280-6.
•   Fayek SA. The value of C4d deposit in post liver transplant liver biopsies. Transpl Immunol. 2012
    Dec;27(4):166-70.
•   Ratner LE, Phelan D, Brunt EM, Mohanakumar T, Hanto DW. Probable antibody-mediated failure of two
    sequential ABO-compatible hepatic allografts in a single recipient. Transplantation. 1993 Apr;55(4):814-9.
•   Musat AI, Agni RM, Wai PY, Pirsch JD, Lorentzen DF, Powell A, Leverson GE, Bellingham JM, Fernandez
    LA, Foley DP, Mezrich JD, D'Alessandro AM, Lucey MR. The significance of donor-specific HLA antibodies
    in rejection and ductopenia development in ABO compatible liver transplantation. Am J Transplant. 2011
    Mar;11(3):500-10.
•   Mengel M, Sis B, Haas M, Colvin RB, Halloran PF, Racusen LC, Solez K, Cendales L, Demetris AJ,
    Drachenberg CB, Farver CF, Rodriguez ER, Wallace WD, Glotz D; Banff meeting report writing committee.
    Banff 2011 Meeting report: new concepts in antibody-mediated rejection. Am J Transplant. 2012
    Mar;12(3):563-70.
•   Dick AA, Horslen S. Antibody-mediated rejection after intestinal transplantation. Curr Opin Organ
    Transplant. 2012 Jun;17(3):250-7.
•   de Kort H, Roufosse C, Bajema IM, Drachenberg CB. Pancreas transplantation, antibodies and rejection:
    where do we stand? Curr Opin Organ Transplant. 2013 Jun;18(3):337-44.
•   Wu T, Abu-Elmagd K, Bond G, Demetris AJ. A clinicopathologic study of isolated intestinal allografts with
    preformed IgG lymphocytotoxic antibodies. Hum Pathol. 2004 Nov;35(11):1332-9.
•   Swanson BJ, Talmon GA, Wisecarver JW, Grant WJ, Radio SJ. Histologic analysis of chronic rejection in
    small bowel transplantation: mucosal and vascular alterations. Transplantation. 2013 Jan 27;95(2):378-82.