Chlamydia pneumoniae in coronary atherosclerotic plaques and coronary instability

Inflammation plays a crucial role in the pathogenesis of acute coronary syndromes (ACS), and the presence of activated T-lymphocytes, who undergo oligoclonal expansion, both in the systemic circulation and in the culprit lesions, strongly suggests specific antigenic stimulation. Several antigens expressed in the atherosclerotic plaques could be suitable in eliciting an immune response, including infectious agents. Chlamydia pneumoniae (Cp) has been found in coronary atherosclerotic plaques but its role in coronary instability has been challenged by the negative results of recent antibiotic trials in ACS. A crucial point in the demonstration of Cp involvement in coronary instability is the association between the presence of the bacterium inside unstable plaques and systemic evidence of active infection. Aim of the present study was to better elucidate the role of Cp infection in coronary instability.