Chlamydia LPS and MOMP seropositivity are associated with different cytokine profiles in patients with coronary heart disease.

Background Persistent Chlamydia pneumoniae infection within atherosclerotic plaques are possible stimulators of inflammation in atherosclerosis. Why the microbe develops persistency in some individuals is unknown, but experimental studies in cell cultures and animals have demonstrated the levels of gamma interferon (IFN gamma) and interleukin 10 (IL-10) to be of crucial importance. Design We wanted to evaluate whether Chlamydia seropositivity in patients with coronary heart disease (CHD) (n = 193) was associated with elevated IFN gamma and IL-10. Two methods for detection of Chlamydia antibodies were included as well as analysis of tumour necrosis factor alpha (TNF alpha), soluble vascular cell adhesion molecule 1 (sVCAM-1) and soluble E-selectin for the evaluation of vascular inflammation. Results We found that patients with IgA antibodies towards Chlamydia lipopolysaccharide (LPS) had elevated levels of IFN gamma (P = 0.048), IL-10 (P = 0.029), TNF alpha (P = 0.009) and sE-selectin (P = 0.045), while Chlamydia LPS IgG seropositivity predicted elevated levels of IL-10 (P = 0.013). Patients with IgA antibodies towards C. pneumoniae major outer membrane protein (MOMP) without simultaneous LPS IgA seropositivity had lower levels of IFN gamma and sVCAM-1 when compared to patients with Chlamydia LPS IgA alone (P = 0.005 for IFN gamma, P = 0.016 for VCAM-1) and patients with combined Chlamydia MOMP and LPS IgA seropositivity (P = 0.046 and P = 0.013, respectively). Conclusions In summary, we demonstrated an association between Chlamydia LPS IgA seropositivity and elevated levels of IFN gamma, IL-10, TNF alpha, sVCAM-1 and sE-selectin in CHD patients that might indicate persistent Chlamydia infection and a proinflammatory state. On the other hand, C. pneumoniae MOMP antibodies were not associated with elevated inflammatory markers and might merely be indicative of past infection, possibly with successful microbe clearance.