Study of acute antibody-mediated rejection in renal allograft biopsies

Introduction. Acute B-cell-mediated rejection (AMR) was ill-defined until the 6(th) Banff meeting establishing the criteria. We performed a retrospective analysis of renal allograft biopsies to evaluate immune injury with reference to the Ahmedabad Tolerance Induction Protocols (ATIP). Methods. We evaluated renal allograft biopsies belonging to 3 groups: group A patients (n = 1.20) underwent a modified ATIP with addition of mesenchymal stem cells, anti-B-cell antibodies, and higher target-specific irradiation; group B patients (n = 351) belong to the old ATIP; and group C (n = 142) were controls who opted out of ATIP. The majority were biopsied 2 or 3 times. Biopsies were subdivided: :<= 60 days, 61 to 180 days, or 181 to 365 days' posttransplant. We compared demographics and diagnoses per the modified Banff criteria. Results. At :560 days' posttransplantation, acute T-cell-mediated rejection (ATIR) was noted in 1.7% of group A patients; 5.98% of B; 33.8% of C with AMR in 11.7% of A; 10.8% of B; and 24.6% of C. At 61. to 180 days' posttransplant, ATIR was absent in group A, 1.99% in group B, and 21.83% in controls, whereas AMR was absent in group A; 1.7% in group B; and 39.4% of controls. At 181 to 365 days, ATIR and AMR were absent in group A; ATIR was 0.56% in group B and 14.1% in controls; AMR was 0.85% in group B and 21.1% in controls. The immunosuppression included cyclosporine (mg/kgBW/day) was 1.5 +/- 0.1 in group A; 2 +/- 0.5 in group B; and prednisone (mg/kgBW/day), 0.15 in group A, 0.2 in group B. The controls received standard doses. Conclusion. The modified ATIP has reduced immunosuppressive drug dose requirements and lessened ATIR; however, AMR, although significantly less than controls, needs to be addressed.