The expression of PD-ligands in APCs and endothelial cells showed that T cell responses in atherosclerotic lesions may be regulated by the PD/PD-L pathway.[123,124] In PD-L1−/−PD-L2−/−Ldlr−/− models, atherosclerosis is increased by an extensive immune response of more activated T cells and high levels of serum TNF-α without PD-1 ligands.[118] Chronic exposure to atherosclerosis-related antigens may lead to PD-1 overexpression and CD8 + T cells inhibition. Here, TNF is linked to atherosclerosis.