A study of HLA-DR and -DQ alleles in 588 patients and 562 controls confirms that HLA-DRB1*03 is associated with recurrent miscarriage

BACKGROUND: Previous studies have demonstrated an association between recurrent miscarriage (RM) and the maternal HLA-DRB1*01 and -DRB1*03 alleles. The primary aim of the present study was to confirm or reject the hypothesis about this association in a larger case-control study. METHODS: HLA-DRB1, -DQA1 and -DQB1 genotyping was carried out by the PCR-sequence-specific primer (SSP) method in 354 patients with unexplained RM and 202 fertile controls. These results were combined with the results from a previous study of 234 RM patients and 360 controls. RESULTS: The prevalence of patients with HLA-DRB1*03 was significantly increased compared with controls [odds ratio (OR) = 1.4, 95% confidence interval (CI) = 1.1-1.9, P = 0.01, P corrected for the number of comparisons (Pc) = 0.02]. In patients with at least four previous miscarriages or with secondary RM, the association became even stronger (OR = 1.8, 95% CI = 1.3-2.5, P = 0.0005, Pc = 0.004; and OR = 1.8, 95% CI = 1.3-2.5, P = 0.0007, Pc = 0.006, respectively). There was no significant differerence between patients and controls with regard to HLA-DRB1*01. CONCLUSION: The HLA-DRB1*03 allele or genes in linkage disequilibrium with it confer susceptibility to RM.