Serological diagnosis of Chlamydophila pneumoniae infection in Greek COPD patients by microimmunofluorescence and ELISA.

Background: The possible role of Chlamydophila pneumoniae infection in episodes of acute exacerbation of COPD (AECOPD) was described in 4-34% of COPD patients, but never in Greece. The possible association of chronic C. pneumoniae infection with disease severity is under study, with a diversity of results reported.

Material/methods: Seventy-five Greek patients with AECOPD were tested for serum C. pneumoniae antibodies using the microimmunofluorescence (MIF) test and ELISA during the first day of their hospitalization and 30 days after enrollment. Serological diagnosis of acute and past C. pneumoniae infection was determined and the sensitivities, specificities, and predictive values of both methods were evaluated. Chronic C. pneumoniae infection was also estimated in both the patient group and a control group.

Results: Seven patients (9.3%) had serological evidence of acute C. pneumoniae infection. Although ELISA and MIF produced equal results for the diagnosis of acute C. pneumoniae infection, the sensitivity and negative predictive value of ELISA for the diagnosis of past C. pneumoniae infection was low when MIF was used as the gold-standard method. Chronic C. pneumoniae infection was more common in COPD patients than in the control group and was even more common in patients with FEV(1)<50%.

Conclusions: Acute C. pneumoniae infection is associated with AECOPD in Greece. ELISA may currently be a valuable diagnostic tool for the diagnosis of acute C. pneumoniae infection, but not for the diagnosis of past infection. The possible role of chronic C. pneumoniae infection in COPD progression needs further investigation.