Valutazione del ruolo delle IgM, IgG, IgA sieriche e delle IgA dello sputo nella diagnosi di polmonite comunitaria da Chlamydia pneumoniae: studio italiano policentrico

To evaluate the incidence of Chlamydia pneumoniae as etiologic agent of community acquired pneumonia (CAP), specific IgM and IgG antibodies anti-C. pneumoniae in serum and IgA in both serum and sputum were detected by a new ELISA-like test (EIA CP-IgG, IgA, IgM – Eurospital, Italy).The study was carried out from January 1999 to July 2001 in sixteen Italian Hospitals on a total of 141 patients with clinical signs of CAP. At a primary inspection (time T-0) serum and sputum samples were taken from 115/141 patients, whereas serum was collected from only 100/141 patients after 30 days (time T-30). At T-0 24/115 (20.8%) patients showed serological markers suggesting primary C. pneumoniae infection. In 23/24 patients the overall serological pattern found at T-0 was confirmed at T-30. In 32/115 patients (27.8%) serological markers of C. pneumoniae suggesting secondary infection were found positive and were confirmed 30 days later. Our data support the possible role played by C. pneumoniae as an important etiologic agent of CAP throughout different geographic areas of Italy.The test was suitable for the laboratory diagnosis of Chlamydia pneumoniae infection. In particular, the presence of specific IgA anti-Chlamydia pneumoniae in both serum and sputum revealed to be useful to define different stages and evolution of infection.