Association of MICA gene polymorphisms with Chlamydia trachomatis infection and related tubal pathology in infertile women.

BACKGROUND: The course and morbidity of Chlamydia trachomatis infections are determined by host genetic factors, virulence of the micro-organism and environmental factors. Major histocompatibility complex class I chain-related A (MICA) gene is highly polymorphic as a potential host genetic candidate. The aim of this study was to investigate the association of polymorphic extracellular domains of MICA with C. trachomatis infection and related tubal factor infertility.
METHODS: Effect of MICA on the susceptibility to C. trachomatis infection and its association with tubal pathology were investigated in 214 infertile women recruited during the period from 2004 to 2007. Subjects were tested for C. trachomatis antibodies, and were further divided into two groups: those with (n = 42) and without (n = 59) tubal pathology based on laparoscopy results. The relationship between prevalence of C. trachomatis, tubal pathology and MICA allele polymorphisms was analysed.
RESULTS: Women with tubal infertility more often had antibodies to C. trachomatis [66.7 versus 39.1%; odds ratio (OR): 3.12, 95% CI: 1.68-5.78, P = 0.004] than infertile women without tubal pathology. Moreover, allele 008 had a highly negative correlation with C. trachomatis infection (P(c) = 0.0036, OR: 2.14), while other allele polymorphisms showed no significant association with the disease. No statistically significant differences were found in the MICA allele frequencies of C. trachomatis-positive women with or without tubal pathology.
CONCLUSIONS: The association of a specific MICA allele with C. trachomatis IgG antibodies among women with infertility suggests that the MICA locus might modify host susceptibility to C. trachomatis infection.