Chlamydia Pneumoniae and Immunoinflammatory Reactions in an Unstable Atherosclerotic Plaque in Humans.

Comparative study of the walls of the aorta, coronary artery, and a. basilaris detected for the first time intra- and extracellular depositions of Chlamydia pneumoniae in unstable atherosclerotic plaques. No chlamydia were detected in the intima of normal sites of the vascular wall and just negligible levels thereof in stable atherosclerotic plaques. An unstable plaque with intra- and extracellular colonies was characterized by infiltration of the cap and intima adjacent to the atheromatous core with mononuclear cells, primarily T cells. These data suggested that Chlamydia pneumoniae could play an important role in the development of immunoinflammatory processes in the vascular wall and promote destabilization and progressive development of atherosclerotic plaques in humans.