Coronary angioplasty induces rise in Chlamydia pneumoniae-specific antibodies

Chlamydia pneumoniae is frequently found in atherosclerotic lesions, and hi gh titers of specific antibodies are associated with increased risk for acu te myocardial infarction, However, a causative relation has not been establ ished yet. We performed a prospective study of 93 patients undergoing percu taneous transluminal coronary angioplasty (PTCA) to investigate whether ang ioplasty influences Chlamydia-specific antibody titers and whether there is an association with restenosis, Blood samples were obtained before and 1 a nd 6 months after angioplasty, Antibodies against chlamydial lipopolysaccha ride and against purified C. pneumoniae elementary bodies were measured by enzyme-linked immunosorbent assay (ELISA). After angioplasty, the prevalenc e of antibodies to lipopolysaccharide rose from 20 to 26% for immunoglobuli n A (IgA), from 53 to 64% for IgG, and from 2 to 7% for IgM (P = 0.021, 0.0 04, and 0.046, respectively). There was a rapid increase of mean antibody t iters of all antibody classes within 1 month of PTCA, During the following 5 months, antibody titers decreased slightly but were still higher than bas eline values. Results of the C. pneumoniae-specific ELISA were essentially the same. The rise of anti-Chlamydia antibodies was not caused by unspecifi c reactivation of the immune system, as levels of antibodies against cytome galovirus did not change. Neither seropositivity nor antibody titers were r elated to restenosis. However, increases in mean IgA and IgM titers were re stricted to patients who had suffered from myocardial infarction earlier in their lives. In conclusion, we show that PTCA induces a stimulation of the humoral immune response against C. pneumoniae. These data support the idea that plaque disruption during angioplasty might make hidden chlamydial ant igens accessible to the immune system.