The influence of the regulatory T lymphocytes on atherosclerosis.

Atherosclerosis is complex inflammatory disease of the arterial wall, in which T lymphocytes play a significant role.1 Since the recognition that T lymphocytes are present in human atherosclerotic plaque nearly 2 decades ago,2 research has focused on the functional importance of these cells in the atherosclerotic process. The majority of T lymphocytes in atherosclerotic lesions are CD4 T-helper cells with a phenotype characteristic of the proinflammatory T-helper 1 (Th1) subset. These cells recognize specifically antigens that are produced in relative abundance in hypercholesterolemic individuals or in plaques including oxidatively modified LDL (Ox-LDL) and HSP60/65. The T cells are activated when macrophage or dendritic cells present these antigens to the T cells in plaques or lymphoid tissues. The Th1 cells produce inflammatory cytokines IFN, tumor necrosis factor (TNF), and membrane CD40-ligand, which amplify the immune response through activation of macrophages, vascular smooth muscle cells, and endothelial cells.1