Abstract
The antigen-specific serological response to Chlamydia pneumoniae was studied in 45 adults with coronary artery atherosclerosis and compared with that in 40 adults with acute respiratory infection. C. pneumoniae antigen and DNA were detected in lesions more frequently in patients with low immunoglobulin G titers against C. pneumoniae than in those with high immunoglobulin G titers. Reactivities with the 42-kDa (46%) and 52-kDa (31%) proteins were observed more frequently in sera from seropositive individuals with atherosclerosis than in sera from patients with acute respiratory infection. Antibodies against the C. pneumoniae-specific 42- and/or 52-kDa protein may be a marker for chronic C. pneumoniae infection.