Role of anti-A/B antibody titers in results of ABO-incompatible kidney transplantation

Background. Our previous studies showed that the incidence of humoral rejection was extremely high in ABO-incompatible living kidney transplantation. This result suggests that anti-A/B antibody titers directly influence the graft survival of ABO-incompatible kidney transplantation. In this study, we examined the impact of preoperative anti-A/B antibody titers on the results of ABO-incompatible living kidney transplantation, Methods, Sixty-seven patients underwent ABO-incompatible living kidney transplantation at our institution between January 1989 and December 1995, The mean age was 34.9 years with 38 males and 29 females. Sixty-one of the 67 recipients were included in an analysis of the impact of anti-A/B antibody titer in longterm graft survival. The remaining six patients were excluded because of death with a functioning graft (three patients) and withdrawal of immunosuppression due to nonimmunological reasons (three patients) within 1 year after renal transplantation. Results. The graft survival rate for the level of less than 1:16 in maximum IgG antibody before transplantation (n = 21) at 1, 5, and 8 years was 81,0, 66,8, and 66,8%, respectively. The corresponding values for the level of 1:32-1:64 (n = 33) and higher than 1:128 (n = 7) were 93,9, 90,5, and 79,7%, and 42,9, 28,6, and 28,6%, respectively (log-rank test, P = 0,0007), There was no significant association between maximum anti-A/B IgM titers, minimum anti-A/B IgM titers, minimum anti-A/B IgG; titers, and graft survival. Conclusions. Preoperative maximum anti-AIS IgG titers correlated with the long-term graft survival in ABO-incompatible living kidney transplantation. Thus, preoperative maximum levels of anti-A/B IgG titers are one of the good predictors of the results of ABO-incompatible living kidney transplantation.