P02 ENHANCED IMMUNOPATHOLOGY EVALUATION OF HUMAN RENAL BIOPSIES USING MULTICOLOR FLOW CYTOMETRY AND CYTOKINE ANALYSIS: A FOCUS ON TRANSPLANTED KIDNEYS

Pre-transplantation anti-major histocompatibility complex class-I related chain A (MICA) sensitization is an uncommon event and its role in kidney graft evolution is not completely defined. Even when kidney allografts are well matched for HLA as in living related transplant and anti-HLA antibodies are not detected, graft rejection can still occur. Anti MICA antibody is reportedly associated with poor transplant outcomes and a high risk of acute and chronic rejection in renal transplantation. Methods: A retrospective study of patients undergone living renal transplantation between years 2000-2014 was performed. Recipients were classified in two groups, pre-transplantation Anti MICA antibody positive group (n1⁄417) and antibody negative comparison group (n1⁄417). Patients with anti HLA antibodies were excluded and only isolated MICA positive patients were included in the study group. Both groups were comparable in recipient age, donor age, donor relation, HLA and immunosuppression. Results: Patients with pre transplant MICA antibody positivity were associated with increased acute rejection rate as compared to comparison group (47% vs 11.7 %, p value1⁄4 0.02). Renal function in MICA positive group and comparison group were comparable over a mean follow up of 6.5 years (mean creatinine 1.58 vs 1.53 mg/ dl). Rate of chronic rejection was same in both groups (5.8%). No patient loss or graft loss occurred in either group over mean follow up of 6.5 years. Conclusions: Isolated Anti MICA antibody positivity is uncommon event. Pre transplant anti MICA antibody positivity is associated with increased acute rejection rates. However chronic rejection rates and renal function are comparable in both groups. Thus our study emphasizes that MICA antibody positive patients may require more aggressive immunosuppression. Role of desensitization has to be defined.