Increased frequency of Chlamydia pneumoniae antibodies in patients with asthma

The worldwide increase in asthma incidences and the impact of the disease o n public health care have led to new Investigations of the cause of the dis ease. Besides well-defined environmental causes, accumulating evidence sugg ests that respiratory tract infections play an important role in the pathog enesis of asthma. Among these microorganisms Chlamydia pneumoniae is an Int racellular pathogen causing persistent infection. Chlamydia pneumoniae infe ction has been discussed as possibly inducing the development of asthma. Th is study was designed to investigate the presence of C. pneumoniae-specific IgG, IgA, and IgM antibodies in serum samples of 33 adults with a clinical history of asthma, positive methacholine test, and reduced FEV1. Patients with asthma were compared with age-, sex-, and locality-matched control sub jects (n = 33). We observed no acute infection either in patients with asth ma or in control subjects, but 63% of all investigated individuals had sign s of past infection. Chlamydia pneumoniae-specific IgA was detected in 52% of the patients with asthma and in 15% of the healthy control subjects (p < 0.01). Serological evidence of chronic infection with C. pneumoniae (high IgG is [greater than or equal to 1:512] and high IgA [greater than or equal to 1:40]) was more frequent in patients with asthma (18.2%) compared with control subjects (3.0%) (p < 0.01). Our results provide further evidence th at chronic infection with C, pneumoniae is linked to asthma.