Role of Anti-MICA Antibodies in Graft Survival of Renal Transplant Recipients of India

INTRODUCTION: The MIC (MHC class I chain-related) genes are a group of nonclassical MHC genes, located in the MHC class 1 region of chromosome 6. The aim of the present study was to find the prevalence of MHC class 1 chain-related (MICA) alloantibodies in patients undergoing live-related donor renal transplantation and its role in short-term graft survival. The role of blood transfusion in the formation of these antibodies was also studied. MATERIALS AND METHODS: Pretransplant samples of patients undergoing renal allograft transplantation were tested for anti-MICA antibodies. Association of various demographics, HLA-A + B + DRB1 mismatches, anti-HLA antibody screen, and anti-MICA antibodies was assessed using Pearson's chi-square test. RESULTS: Out of 646 serum samples, 94 (14.6%) were positive and 552 (85.4%) were negative for anti-MICA antibodies. Patients with anti-MICA antibody had a graft survival 89.3% as compared to 94.7% in patients without anti-MICA antibody (P < 0.05). The hazard ratio for all patients was 3.0701 (P < 0.05). Out of the 340 patients with no HLA antibodies, the presence of anti-MICA antibodies without any HLA antibodies (n = 43) was associated with poor outcome in the patients (hazard ratio of 2.768, P < 0.05). The presence of MICA antibodies with HLA antibodies did not decrease the graft survival (hazards ratio of 1.3750, P > 0.05). CONCLUSION: Preformed MICA antibodies independently increase the risk of kidney rejection and therefore recommend that guidelines should be formed for mandatory testing of these antibodies prior to renal transplant.