HLA Class I and II Polymorphisms and Trachomatous Scarring in a Chlamydia trachomatis-Endemic Population

Abstract

Immune responses to Chlamydia trachomatis contribute to protection from infection and to immunopathologic disease. To test whether subjects' HLA class I (A, B, and Cw) or class II (DRβ1 and DQβ1) types influence risk of trachomatous scarring from chronic infection with C. trachomatis, 153 cases and pair-matched controls in Gambia were studied. No HLA type was associated with protection from scarring, indicating that protective immune responses are not limited to only one or a few HLA-restricted epitopes in C. trachomatis antigens. One class I antigen, HLA-A28, was significantly more common among cases than controls (25.8% vs. 15.9%, respectively; McNemar's odds ratio [OR], 1.88; 95% confidence interval [CI] = 1.01–3.49; P = .046). In DNA subtyping of the A28 specificity, the A *6801 allele was equally common among cases and controls, but the A *6802 allele was significantly overrepresented among cases (McNemar's OR, 3.14; 95% CI = 1.32–7.44; P = .009). This association may be due to an immunopathologic HLA-A *6802-restricted cytotoxic T lymphocyte response.