Molecular genetic studies on the compatibility of HLA class II alleles in patients with unexplained recurrent miscarriage in the Japanese population.

It is hypothesized that patients having unexplained recurrent miscarriage lack an appropriate immune reaction against their partner's antigens, which means possible compatibility of HLA antigens between the patient couples. The conclusion, however, has not yet been achieved, so the purpose was to determine whether significant compatibility of HLA class II exists between the couples. The HLA-DRB1 and -DQB1 genotypes were determined using PCR-RFLP method in 91 patient couples and in 72 normal couples. The number of patient couples with zero-allele mismatch was not significantly different compared with that of control couples regarding HLA-DRB1 genotype and phenotype, as well as regarding HLA-DQB1 genotype and phenotype. While the number of patient couples with zero- and one-allele mismatch was significantly higher compared with that in control as to HLA-DR and -DQ phenotype (P=0.029 by Chi-square test). In conclusion, it is suggested that the compatibility of HLA class II antigens between couples might be involved in the genesis of unexplained recurrent miscarriage.