Printed in UK- all rights reserved Copyright ERS Journals Ltd 1994 European Respiratory Journal

ABSTRACT: Respiratory infections precipitate wheezing in many asthmatic patients and may be involved in the aetiopathogenesis of asthma. Several studies have demonstrated that viral infections may provoke asthma. Bacterial infections seem to play a minor role. However, Chlamydia pneumoniae has been recently reported as a possible cause of asthma. The aim of the present study was to evaluate the role of C. pneumoniae infection in acute exacerbations of asthma in adults. Seventy four adult out-patients with a diagnosis of acute exacerbation of asthma were studied. Acute and convalescent (≥3 weeks) serological determination of antibodies to cytomegalovirus, respiratory syncytial virus, adenovirus, influenza A and B, parainfluenza 1 and 3, Mycoplasma pneumoniae and Legionella pneumophila were performed by means of immunofluorescence tests. C. pneumoniae specific antibodies were detected by two microimmunofluorescence tests using a specific antigen (TW-183) and a kit with three chlamydial antigens. Pharyngeal swab specimens were also obtained for C. pneumoniae identification. Samples for bacterial culture were obtained in patients with productive cough (15 out of 74 patients)