CHLAMYDIA-PNEUMONIAE SEROPREVALENCE AMONG HIV-1-INFECTED AND UNINFECTED PEOPLE WITH KNOWN HIV RISK FACTOR

Objective: To evaluate the prevalence of Chlamydia pneumoniae antibodi es in an Italian population of HIV-infected and uninfected individuals in relation to the presence of HIV risk factors. Design and methods: A prospective evaluation of C. pneumoniae microimmunofluorescence immu noglobulin (Ig) G and IgM titres, in relation to sex, age, HIV clinica l stage, and the presence of different HIV acquisition risk factors. S etting: The Department of Infectious and Tropical Diseases, a secondar y and tertiary care institution in the 'La Sapienza' University of Pom e, during 1994 and 1995. Participants: HIV-infected and uninfected sub jects (n = 322), all of them without respiratory symptoms. Results: A statistically significant higher C. pneumoniae seroprevalence was foun d to be related, by multivariate analysis, to sex, age, and presence o f HIV risk factor, but not to the presence of HIV infection itself. Am ong HIV-positive subjects, C, pneumoniae seroprevalence appeared to de crease with absolute CD4+ cell count and was low in Centers for Diseas e Control and Prevention (CDC) stage C of HIV infection. Furthermore, high C. pneumoniae Ige titres (greater than or equal to 1 : 512) were not found in subjects with CDC stage C disease or in those with low CD 4+ cell count (< 200x10(6)/l). Conclusion: C. pneumoniae seroprevalenc e is higher in injecting drug users and in subjects with promiscuous h eterosexual activity. A previous report of a higher C. pneumoniae sero prevalence among HIV-1-infected subjects (in relation to the normal po pulation) was probably due to the presence of HIV risk factor and not to the HIV infection itself. HIV-infected subjects seem to have progre ssively lost their C. pneumoniae IgG antibodies in middle and advanced stages of HIV infection. High C. pneumoniae IgC titres are rarely fou nd in advanced stage HIV-infected patients.