Immunogenetic correlates for Chlamydia trachomatis–Associated tubal infertility

To understand immunogenetic mechanisms of Chlamydia trachomatis infection and tubal scarring. We measured and compared previously significant human leukocyte antigen (HLA) class II DQ alleles, their linked DRB genes, and polymorphisms in selected cytokine genes (tumor necrosis factor α-308 promoter; transforming growth factor β1-10 and -25 codons; interleukin 10-1082, -819, and -592 promoters; interleukin 6-174 promoter; and interferon γ+874 codon 1) among Kenyan women with confirmed tubal infertility with and without C trachomatis microimmunofluorescence antibody. Two class II alleles, HLA-DR1*1503 and DRB5*0101, were detected less commonly in C trachomatis microimmunofluorescence seropositive women than in C trachomatis microimmunofluorescence seronegative women with infertility (0% versus 20%; odds ratio [OR] 0.05; 95% confidence interval [CI] 0, 0.7, and 6% versus 26%; OR 0.2; 95% CI 0.02, 1.0, respectively). These alleles are commonly linked as a haplotype at the DRB locus. This finding could not be explained through linkage disequilibrium with the other studied HLA or cytokine genes. These alleles may lead to an immunologically mediated mechanism of protection against C trachomatis infection and associated tubal damage, or alternatively increase risk for tubal scarring due to another cause.