Molecular genetic studies of HLA-DRB1 alleles in patients with unexplained recurrent abortion in the Japanese population

BACKGROUD: Recently, evidence that HLA antigens are markers for recurrent spontaneous abortion has gained increased attention. Although the association between HLA class II antigens and patients with unexplained recurrent abortion was elucidated by a large population study in a Caucasian population, such analyses have been conducted in only a small Japanese population. The aim of the present study was to determine whether HLA-DR antigens are associated with patient populations with unexplained recurrent abortion in the Japanese population. METHODS: HLA-DRB1 genotypes were determined using a PCR-restriction fragment length polymorphism (PCR-RFLP) method in 93 patients with unexplained recurrent abortion (79 primary recurrent aborters; and 14 secondary recurrent aborters) and in 115 normal fertile women. The rate of possession of each HLA-DRB1 genotype was compared among the three populations. RESULTS: The rate of possession of the HLA-DRBI*1502 in patients with secondary recurrent abortion was significantly higher (P < 0.01 after correction for multiple comparisons) compared with the control, fertile women. The rate of possession of HLA-DRB1*1502 was also higher in patients with primary recurrent abortions than in controls, but the difference was not statistically significant after correction. CONCLUSIONS: These findings suggest that HLA-DRB1*1502 might be a risk allele for unexplained recurrent abortion in the Japanese population.