Updates in the Diagnosis & Management of Cellular Rejection
Summary of CME Lecture by Thomas Schiano, MD, FAASLD
1. Main Clinical Topics Discussed
- Mechanisms and classification of T-cell-mediated rejection (TCMR) following liver transplantation
- Distinction between early and late acute cellular rejection (ACR)
- Histologic assessment using the Banff Rejection Activity Index (RAI)
- Management strategies for mild, moderate/severe, and steroid-resistant rejection
- Chronic rejection: early recognition and management
- Antibody-mediated rejection (AMR) as a diagnostic consideration
- Clinical pitfalls and complicating factors in rejection therapy
2. Key Learning Points, Guidelines, and Recommendations
Immunosuppression Mechanisms
- Calcineurin inhibitors (CNIs): tacrolimus and cyclosporine remain the cornerstone of post-transplant immunosuppression
- mTOR inhibitors and antithymocyte globulin (ATG) used in severe rejection or as induction agents
Early vs. Late TCMR
- Late TCMR is defined as occurring >6 months post-transplant and carries a significantly worse prognosis than early rejection
- Histologic features of late TCMR are atypical and may delay diagnosis:
- Plasma cells, interface hepatitis, piecemeal necrosis
- Centrilobular and perivenular inflammation
- More lymphocytic infiltrate; less vascular and bile duct injury compared to early TCMR
- Idiopathic post-transplant hepatitis should be considered late TCMR until proven otherwise
- Steroid resistance is significantly more common in late TCMR
- Higher risk in recipients transplanted for autoimmune liver diseases (PBC, PSC, autoimmune hepatitis)
Banff Rejection Activity Index (RAI)
- Established by consensus in 1997; remains the standard histologic scoring tool
- Scores portal inflammation, bile duct inflammation, and endothelial (venous) inflammation (each 1–3)
- Cumulative score guides severity classification; however, histologic severity does not reliably correlate with long-term outcomes
Management by Severity
- Mild rejection: Optimize CNI trough levels; consider adding or increasing mycophenolate mofetil (MMF); consider switching cyclosporine to tacrolimus
- Moderate/severe rejection: Methylprednisolone 500 mg IV for 2–3 days
- Steroid-resistant rejection: Repeat biopsy to reassess; evaluate for donor-specific antibodies (DSA); consider ATG with caution given significant infection risk
Chronic Rejection
- Now less common due to improved immunosuppressive management
- Classic features: bile duct loss ("vanishing bile duct syndrome"), foam cell arteriopathy
- Early chronic rejection may lack classic findings—vigilance is essential
- Management: maximize CNI therapy; switch to tacrolimus if on cyclosporine; consider adding MMF or mTOR inhibitor (sirolimus/everolimus); limited role for steroids in absence of significant inflammation
3. Specific Clinical Data, Statistics, and Study Results
- Levitsky et al. (2016) — Analysis of A2ALL (live donor database) and SRTR:
- Development of TCMR worsens patient survival and graft survival at all time points post-transplant
- TCMR in live donor recipients: ~8-fold increase in mortality; >6-fold increase in graft failure
- No significant impact of histologic severity of rejection on long-term outcomes
- King's College UK Study (late ACR):
- Late ACR more common in PBC recipients
- Mean time to late rejection: ~18 months post-transplant
- Significantly higher graft loss rates compared to early ACR
- Clear reduction in 10-year survival compared to early rejection cohorts
- UK Study (>230 patients, early rejection): No statistically significant relationship between RAI severity score and death, graft failure, re-transplantation, or chronic rejection
- ATG for steroid-resistant rejection: