Polymorphisms in candidate genes and risk of scarring trachoma in a Chlamydia trachomatis--endemic population.

Genes involved in regulating antimicrobial immunity and inflammation may modulate the risk of tissue scarring and fibrosis in chlamydial diseases such as trachoma. By use of a large case-control study of scarring trachoma in The Gambia, the importance of single-nucleotide polymorphisms in several candidate genes was investigated. Overall, no significant differences were found between patients and control subjects in genotype frequencies for polymorphisms in cytokine promoters interleukin (IL)-10 (positions -1082, -819, -592), IL-4 (-590), or tumor necrosis factor-alpha (-376) or for codon 57 of the mannose-binding protein. Among the ethnic groups in the study, Mandinkas had the highest frequency of the IL-10-1082G allele (0.36). Within this ethnic group, the IL-10-1082G homozygote genotype was significantly more common among case patients than control subjects (odds ratio, 5.10; 95% confidence interval, 1.24-24.2; P=.009). This single association is consistent with data indicating that the IL-10-1082G allele is associated with higher levels of IL-10 transcription and that Th2-type immune responses are associated with risk of chlamydial disease.