Seroprevalence of antibodies to Chlamydia spp. in human immunodeficiency virus-infected subjects in Japan.

To evaluate the seropositivity of Chlamydia spp. in human immunodeficiency virus (HIV)-infected subjects in Japan, Chlamydia-specific antibodies in sera collected from 106 HIV-infected subjects were measured by the microimmunofluorescence test. The prevalence of C. pneumoniae-specific IgA, C. trachomatis-specific IgG and IgA and mean titers were significantly higher in the homosexual and heterosexual HIV-infected subjects than in the hemophilic patients and HIV-negative controls. These data indicate that the higher C. pneumoniae and C. trachomatis seroprevalence among HIV-infected subjects is probably due to an HIV risk factor, such as promiscuous sexual behavior, rather than to HIV infection itself.