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/CWL-029) were determined by an in-house developed enzyme immunoassay.

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 1 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.