[Monocytes/macrophages and lipidosis of the human aortic intima in atherosclerosis]

Immunomorphological and histochemical studies were carried out on the aorta serial sections of 20-40-year-old males. The results demonstrate that monocytes appear in the aortal intima after fat deposition. Intensification of lipoidosis in the aorta promotes an increase in monocyte count in the intima. Enzymes utilizing fat in the macrophages were not revealed at early stages of lipoidosis. Activation of lipoidosis is followed by the appearance of acid lipase, acid phosphatase and nonspecific esterase in monocytes. This is evidence of these cells capacity to phagocyte and utilize fat. The quantity of these cells increases with intensification of lipoidosis. Monocytes/macrophages are expressing HLA-DR antigen on their surface, this expressing their active immunological state.