CD68 and endothelial dysfunction: In our previous study of aortas from SIV/SHIV-infected RM, we found CD8 T cells in proximity to CD68+ macrophages at sites of endothelial dysfunction [13], and we have recently observed that activated CD8 T cell production of TNF induces monocyte surface expression of tissue factor [15], an initiator of the extrinsic coagulation cascade [61].