Chlamydia trachomatis and HIV infection

To study the interactions between Chlamydia trachomatis (CT) and human immunodeficiency virus (HIV) infections, we examined CT serologies in sequential serum samples of male homosexuals (MHS), followed over a mean period of 4 years. Of the MHS studied, 77 were HIV(-), 18 were HIV(+) and 10 patients seroconverted during the study period. Seventy matched heterosexual controls were tested concomitantly. CT-specific antibodies of both IgG and IgA isotypes were determined by an immunoperoxidase assay, indicating past and active infection respectively. Anti-CT IgG was frequently observed in both HIV(-) and HIV(+) MHS (40-50% vs. 23% of controls) and IgA antibodies were also common in both MHS groups (15-20% vs. 1.5% of controls). After HIV infection, no increase in CT antibodies occurred. We found serological data suggestive of active CT infection preceding seroconversion in 3 of 10 seroconverters vs. 5% of matched MHS controls who remained HIV(-) (P < 0.025), indicating a possible effect of CT infection on the acquisition of HIV should be further studied.