Studies on the human leukocyte antigen-DR in patients with endometriosis: genotyping of HLA-DRB1 alleles.

BACKGROUND An increasing number of reports suggest that endometriosis is associated with abnormal immune function involving changes in both cell-mediated and humoral immunity, although the aetiology of the disease remains undefined. The human leukocyte antigen system (HLA) is known to play a role in the aetiology of a number of diseases. This study examines the possible association between the HLA-DR and endometriosis. METHODS Eighty-three patients diagnosed with endometriosis by laparoscopic examination were typed for HLA-DR antigens using a PCR-restriction fragment length polymorphism analysis. The frequency of HLA-DR genotypes in this patient population was compared with that in a population of general controls. RESULTS The incidence of HLA-DRB1*1403 in the patient group was 6.0% (10/166 alleles) compared with 1.4% in the control group (6/444 alleles), and the incidence of the HLA-DRB1*1403 allele was significantly greater in patients with endometriosis compared with the control population [odds ratio 4.68, 95% confidence interval 1.67-13.09, P = 0.0013 (chi(2) analysis), (corrected P values: Pc = 0.0494)]. No significant difference was found between the two groups with regards to the frequency of the other HLA-DR alleles. CONCLUSIONS The results from this study may be helpful to implicate a role of HLA-DR antigens in the development of endometriosis, although further investigation is required.