OBJECTIVETo investigate the risk factors for sensitization of anti-MICA antibodies and their impact on the outcomes of renal transplantation.

METHODSLuminex flow cytometry were used to identify 10 MICA antibodies and evaluate the antibody specificity in 98 uremic patients positive or negative for anti-MICA antibodies undergoing kidney transplantation. The factors contributing to MICA sensitization were analyzed, and the incidence of acute rejection and graft function recovery time were compared between the positive and negative cases for anti-MICA antibodies.

RESULTSOf the 98 uremic patients, 16 (16.3%) were positive for anti-MICA antibodies. The positive and negative cases showed significant differences in the history of blood transfusion, pregnancy, transplantation, and PRA status (P<0.05). In the 38 renal transplant recipients, 6 experienced acute graft rejection, which was reversed by methylprednisolone pulse therapy; of the 10 recipients positive for anti-MICA antibodies, 4 showed acute graft rejection as compared to 2 out of the 28 recipients negative for anti-MICA antibodies (P=0.031). The cases positive for anti-MICA antibodies showed a significantly longer graft function recovery time than the negative cases (14.6∓4.7 vs 8.2∓4.5 days, P=0.001).

CONCLUSIONSBlood transfusion, pregnancy, and transplantation all contribute to the production of anti-MICA antibodies. Patients positive for anti-MICA antibodies may require strict HLA matching and more potent immunosuppressive drugs to prevent renal graft rejection and improve graft survival.