Human leukocyte antigen class II DQ alleles associated with Chlamydia trachomatis tubal infertility.

OBJECTIVE To investigate epidemiologic tubal infertility risk factors and the relationship between HLA class II alleles and Chlamydia trachomatis tubal infertility. METHODS Forty-seven women with tubal infertility and 46 fertile controls were studied in Nairobi, Kenya. A questionnaire was administered and serum collected for measurement of C trachomatis antibodies. HLA class II molecular typing was done with DNA extracted from peripheral blood lymphocytes. The prevalence of C trachomatis microimmunofluorescence antibody, chlamydia heat shock protein 60 antibody, and HLA class II alleles was compared among cases of tubal infertility and fertile controls. RESULTS Women with tubal infertility more often had histories of pelvic inflammatory disease (15% versus 0%; odds ratio [OR] 16; 95% confidence interval [CI] 5.5, 47) histories of spontaneous abortion (34% versus 7%; OR 6.7; 95% CI 2.8, 16), and antibodies to C trachomatis (53% versus 26%; OR 3.2; 95% CI 1.3, 7.7) than controls. Among infertile women, DQA*0101 and DQB*0501 alleles were positively associated with C trachomatis tubal infertility (OR 4.9; 95% CI 1.3, 18.6, and OR 6.8; 95% CI 1.6, 29.2, respectively). DQA*0102 was negatively associated with C trachomatis tubal infertility (OR 0.2; 95% CI 0.005, 0.6). CONCLUSION Chlamydia trachomatis infection is an important cause of tubal infertility in Nairobi. The association of specific HLA class II alleles with C trachomatis microimmunofluorescence seropositivity among women with tubal infertility suggests that the DQ locus might modify susceptibility to and pathogenicity of C trachomatis infection.