Serum IgG subclasses levels in paediatric patients with pneumonia.

OBJECTIVES To determine the IgG subclass levels of patients admitted to Harare Central Hospital paediatric wards with pneumonia. DESIGN A cross sectional study. SETTING Harare Central Hospital, Departments of Immunology and Paediatrics, University of Zimbabwe; Department of Paediatric Immunology, University of Utrecht, The Netherlands. SUBJECTS 56 paediatric patients. MAIN OUTCOME MEASURES IgG subclass profiles of children with pneumonia. RESULTS Of the 56 children tested, 40 (71%) had antibodies to human immunodeficiency virus (HIV). The levels of IgG1 and IgG3 subclasses were significantly higher in HIV antibody positive children (p < 0.001, p < 0.01 respectively) than in those without detectable HIV antibodies in their sera. There was no significant relationship between IgG subclass levels and the presence of HIV p24 antigen. Furthermore, age and gender also had no significant influence on the levels of IgG subclasses in this population. CONCLUSION High levels of IgG1 and IgG3, but not IgG2 and IgG4, occur frequently in children with pneumonia and are associated with the presence of HIV antibodies.