High sensitivity C-reactive protein and immunoglobulin G against Chlamydia pneumoniae and chlamydial heat shock protein-60 in ischemic heart disease.

BACKGROUND Inflammation and infectious agents such as Chlamydia pneumoniae have been associated with cardiovascular disease. OBJECTIVE To evaluate the serum high sensitivity C-reactive protein (hs-CRP) and antibodies against Chlamydia pneumoniae and Chlamydial heat shock protein-60 (Cp-HSP-60) in patients with ischemic heart disease (IHD). METHODS 62 patients with IHD having either acute myocardial infarction (AMI; n=31) or unstable angina (UA; n=31) and 31 sex- and age- matched healthy subjects as a control group were enrolled in this study. Serum samples of participants were tested for the presence of hs-CRP and antibodies against C. pneumoniae and Cp-HSP-60 using ELISA method. RESULTS The seroprevalence of anti-C. pneumoniae antibody in AMI group (93.5%) or UA group (90.3%) was significantly higher than the control group (61.3%; p<0.001). The seroprevalence of anti-Cp-HSP60 IgG was 22.6% in healthy subjects with mean end titer of 43.1+/-6.32. The seropositive rates of anti-Cp-HSP60 were 48.4%, 54.8% and 51.6% in AMI, UA and the overall IHD groups with mean end titers of 94+/-22.86, 113.8+/-24.25 and 103.9+/-16.57, respectively. Both the seroprevalence and the mean titer of anti-Cp-HSP60 in patients groups were significantly higher than those observed in the control group (p<0.04 and p<0.03, respectively). Moreover, the mean serum hs-CRP levels was significantly higher in the IHD group as compared to the control group (21.6 microg/ml+/-3.73 vs 2.5 microg/ml+/-0.52; p<0.00001). The mean serum hs-CRP levels of AMI (30.3 microg/ml+/-6.07) or UA (12.9 microg/ml+/-3.85) groups were also significantly higher than those observed in the control group (p<0.00001 and p<0.001, respectively). Furthermore, the difference of the mean serum hs-CRP levels between AMI and UA groups was also significant (p<0.02). CONCLUSIONS These results showed that the seroprevalence of antibodies against C. pneumoniae and Cp-HSP-60 and the serum levels of hs-CRP and anti-Cp-HSP60 IgG were higher in patients with IHD.