To determine types of cells populating subendothelial space of human aortic intima we used commercially available monoclonal antibodies to smooth muscle cells, to monocyte-macrophages and to leucocytes. Antibodies to pericytes were obtained from our colleagues from the netherlands. These two antibidies stain pericytes in different states. 3g5 stains non-activated pericytes but 2a7 reveals proliferating pericytes.