A renal transplant recipient develops de novo donor-specific antibodies (DSA) against HLA-DQ 3 months post-transplant with stable creatinine. Biopsy shows peritubular capillary C4d deposition and microvascular inflammation. This is classified as:

• A T-cell mediated rejection (TCMR)
• B Chronic active TCMR
• C Borderline changes — no treatment required
• D Active antibody-mediated rejection (ABMR) ✓

Explanation

The Banff 2022 classification defines active antibody-mediated rejection (ABMR) by: (1) histological evidence of microvascular injury (glomerulitis, peritubular capillaritis), (2) C4d staining in peritubular capillaries, and/or (3) positive DSA. Active ABMR requires at least one criterion from each of two categories. This patient has all three hallmarks. Treatment includes plasmapheresis, IVIG, rituximab, and optimization of maintenance immunosuppression. Active ABMR carries a poor prognosis with median graft survival of 5–7 years without intervention.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.