Compatibility of HLA-A and -B Antigens in Patients with Unexplained Recurrent Abortion

To elucidate whether there is significant compatibility of HLA class I antigens between spouses of unexplained recurrent abortion in the Japanese population, HLA-A and -B antigens were determined by a microcytotoxicity method in 122 patient couples with unexplained recurrent abortion and in 60 normal fertile couples. The 122 patients were divided into primary recurrent aborters and secondary recurrent aborters. They were also divided according to positivity of the MLR (mixed lymphocyte culture reaction)-blocking antibodies (MLR-BAbs). The numbers of incompatible antigens in those couples with unexplained recurrent abortion were determined and compared with those in the control couples. The mean numbers of incompatible HLA-A and -B antigens in couples with recurrent aborters (n=122), and control couples (60) were 2.67±0.97, and 2.83±0.93, respectively, indicating no significant different. The mean numbers of incompatible HLA-A and -B antigens in couples with primary recurrent aborters (n=106) and secondary recurrent aborters (n=16) were 2.68± 0.98, and 2.63±1.02, respectively. These numbers were not significantly different compared with those in the control couples. Those in couples with negative MLR-BAbs (n=105) and with positive MLR-BAbs (n=17) were 2.70±0.66 and 2.53±1.07, respectively, values which were also not significantly different compared with those in the normal control couples. These findings suggest that the compatibility of HLA-A and -B antigens betwee couples is not involved in the genesis of unexplained recurrent abortions in the Japanese population.