AEGiS-14IAC: Chlamydia pneumoniae prevalence by antibody, PCR and a novel gamma interferon release assay in HIV infected and uninfected persons.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Chlamydia pneumoniae prevalence by antibody, PCR and a novel gamma interferon release assay in HIV infected and uninfected persons.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. B10229)

Woolley IJ, Jones S, Gahan ME, Jasenko I, Johnsen SP, Wesselingh S, Fuller A, Birkelund S, Christiansen G, Ostergaard L
Alfred Hospital/ Monash University, Prahran, Australia

BACKGROUND: There has been increasing interest in potential risk factors for cardiovascular disease in persons with HIV. One association identified in HIV negative individuals is Chlamydia pneumoniae. Previous studies have shown increased rates of C pneumoniae infection in AIDS patients however they have used predominately IgG and IgM levels wheras IgA is probably the best antibody marker of long term infection and cellular response is the basis of immunity. We are developing an assay for detection of Gamma-IFN in full blood against C. pneumoniae based on QuantiFERON. The results will be compared with antibody responses and PCR on monocytes"

METHODS: Blood samples were taken from 32 healthy volunteers and 34 HIV infected patients of the Alfred Hospital. They were then tested for IgG and IgA using the LOY-EIA assay (Labsystems, Helsinki, Finland). Cell mediated immune responses were measured by the release of gamma interferon from whole blood cultures stimulated with C. pneumoniae elementary bodies and C. pneumoniae DNA in monocytes by a nested PCR.

RESULTS: see Table below [table: see text]By Fischers' exact test comparing antibody response for immunity (isolated IgG) and antibody response asociated with chronic infection (any IgA) there was a borderline asociation with HIV positivity (p=0.1)

CONCLUSIONS: 1. overall seroprevalence was similar in both HIV positive and negative individuals 2. the antibody responses in HIV positive individuals were more characteristic of chronic infection rather than immunity (p=0.1) therefore HIV patients then may be more prone to develop chronic C. pneumoniae infection which might contribute to an increased risk of cardio-vascular diseases in this group of patients.

Keywords: AEGIS, Chlamydophila pneumoniae, Prevalence, HIV, Chlamydia Infections, Antibodies, Polymerase Chain Reaction, Antibodies, Bacterial, Interferon Type II, Immunoglobulin G, Seroepidemiologic Studies, HIV Seropositivity, Immunoglobulin M, Immunoglobulin A, Infection, Risk Factors, Finland, Human, Epidemiology, immunology

020707
B10229