OBJECTIVES: HIV-1 infected patients are known to develop frequently respiratory tract infections. Among common pathogens, Chlamydia Pneumoniae (CP) is drawing increasing attention as a respiratory pathogen in adult HIV-1 infected subjects. Yet, to date there are no data regarding HIV-1 pediatric population. METHODS: We enrolled 36 children with vertically transmitted HIV-1 infection and 36 HIV-1 negative controls matched for age (range 5m-9y/3m--median 4y/9m) and sex, who were drawn 6ml of venous blood to perform HIV-1 test (ELISA and WB) and microimmunofluorescence test for IgG and IgM Antibodies specific to CP antigen. For the babies under 15 months of age HIV-1 infection was demonstrated by viral culture and polymerase chain reaction (at least two positive determinations). We used the CDC classification system for HIV-1 infection in pediatric age: all the 36 HIV-1 infected children were clinically symptomatic. RESULTS: CP specific IgG was found in 5 out of 36 (14%) HIV-1 positive and 2 out of 36 (6%) negative children (p = ns). CONCLUSIONS: CP seroprevalence in HIV-1 infected children seems to be slightly higher even though not significantly compared to HIV-1 negative control group. These data deserve further studies on the pathogenetic role of CP in HIV-1 infected children.

Acquired Immunodeficiency Syndrome/COMPLICATIONS/*MICROBIOLOGY Antibodies, Bacterial/*ANALYSIS Child Child, Preschool Chlamydia pneumoniae/IMMUNOLOGY/*ISOLATION & PURIF Chlamydia Infections/COMPLICATIONS Human *HIV-1 IgG/ANALYSIS IgM/ANALYSIS Infant ABSTRACT

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