Changes in antibody titers against Chlamydia pneumoniae after coronary angioplasty

Objectives: The potential role of common infectious agents in the pathogenesis and progression of atherosclerosis has been studied increasingly over the last decade. The evidence for Chlamydia pneumoniae as a potential causative agent is strong and is based on the findings of numerous sero-epidemiological studies, examination of atheromatous plaque specimens, in vitro animal models. We performed a prospective study in percutaneous transluminal coronary angioplasty (PTCA) patients to investigate whether the angioplasty procedure influenced the specific humoral immune response reaction against C. pneumoniae antigens. Methods: We studied 76 patients who successfully underwent PTCA for de novo lesions. Blood samples were drawn immediately before PTCA and 1 month after PTCA. IgG and IgA antibodies against C. pneumoniae (strain CDC/CY&-029) were determined by an in-house developed enzyme inummoassay. Results: At the time of angioplasty 75% and 34% of the patients had seropositive antibodies to elementary bodies (EBs) of classes IgG and IgA, respectively. Mean titers of IgG antibodies before and I month after PTCA were 46 +/- 31 and 50 +/- 28 relative units (RU/ml) (P > 0.05). One month after PTCA, 97% and 34% of the patients had seropositive antibodies to EBs of classes IgG and IgA, respectively. We divided our patients into two groups on the basis of IgG seropositivity (group I: Chlamydia antibody IgG seronegative patients, group II: Chlamydia antibody IgG seropositive) before PTCA. Significant increase in the antibody titers of IgG (12 5 vs. 40 18, P < 0.001) and IgA (0.6 +/- 0.33 vs. 1.15 +/- 0.83, P = 0.007) was observed in group I patients 1 month after PTCA and 88% of them gained IgG seropositivity. There were no significant changes in IgG and IgA antibody levels in group II after PTCA. Conclusion: We have demonstrated a statistically significant rise in C. pneumoniae antibodies (especially IgG) induced by PTCA in patients previously seronegative. (C) 2003 Elsevier Ireland Ltd. All rights reserved.