[The immune system, atherosclerosis and persisting infection]

The paper demonstrates that lymph nodes situated in the vicinity of magistral blood vessels are the source of immune and inflammatory response to LDL as the main pathogenetic factor in atherosclerosis. The activation of T-cell-mediated immunity takes place in them at the very early stages of the disease, resulting in forming of CD4+T-lymphocytes, activated mononuclear cells and immunostabilizing B-lymphocytes. The cell changes in lymph nodes correlate with the severity of atherosclerotic lesions in the vessel intima and closely reflect the peculiarities of immune inflammation development in fatty streaks and atherosclerotic plaques in human atherogenesis. A paradoxical reaction was observed in cases with Chlamydia pneumoniae found in the wall of aorta and paraaortal lymph nodes. No evident immune response on the part of immunocompetent cells took place, but, on the contrary, the function of mononuclear cells, including T-lymphocytes, was suppressed. This phenomenon may be explained by the fact that intracellular localization of Chlamydia pneumoniae hides it from immune system control or by the possible microorganism capability of direct immunosuppressive influence on lymphoid cells both in the blood vessel wall and in regional lymph nodes.