BACKGROUNDSensitized recipients have a high risk of immunological graft loss due to hyperacute rejection and/or accelerated acute rejection. The presence of major histocompatibility complex class I-related chain A (MICA) antibodies has also been described associated with an increased rate of kidney-allograft rejection. The aim of this study was to describe the expression of MICA antibodies in sensitized recipients of renal transplantation and evaluate its influence on the kidney transplantation recipients.

METHODSA total of 29 sensitized recipients were included in this study. All patients received the MICA antibodies detection before and after protein A immunoadsorption. Panel reactive antibody (PRA), HLA-matches, acute rejection and postoperative one to four-week serum creatinine level were also collected and analyzed, respectively. No prisoners were used in this study.

RESULTSEight patients (27.6%) in all 29 sensitized recipients expressed the MICA antibodies but did not show higher acute rejection rate than the non-expressed patients (3/8, 37.5% vs. 8/21, 38.1%; P = 1.000). Recipients with PRA > 40% showed higher expression levels of MICA antibodies than the recipients with PRA < 40% (7/16, 43.8% vs. 1/13, 8.3%; P = 0.044). HLA mismatch did not have any effect on the expression of MICA antibodies (P = 1.000). MICA antibodies positive group had higher serum creatinine level than the control in postoperative one week ((135.4 ± 21.4) µmol/L vs. (108.6 ± 31.6) µmol/L, P = 0.036), but no significant difference in postoperative four weeks ((89.0 ± 17.1) µmol/L vs. (77.1 ± 15.9) µmol/L, P = 0.089). MICA antibodies decreased significantly after protein A immunoadsorption.

CONCLUSIONSMICA antibodies increase in the sensitized recipients, which have significant effects on the function of allograft in early postoperative period. Protein A immunoadsorption can decrease MICA antibodies effectively in sensitized recipients.