Dendritic cells in venous pathologies

Dendritic cells are potent antigen-presenting cells responsible for the act ivation of T-lymphocytes in various immune responses. Their role in the ini tiation of immune reactions in allergies, autoimmune diseases, tumors, tran splantation, and, more recently, in atherosclerosis has been well establish ed, but their involvement in venous pathologies has not been previously inv estigated. The aim of this study was to determine whether dendritic cells a re present in veins affected by varicosity and thrombophlebitis. Three grou ps of veins obtained at operation were studied: (1) varicose veins of the g reat saphenous vein from patients who were undergoing vein stripping for pr imary varicosity; (2) segments of the great saphenous vein from patients wi th varicosity complicated by thrombophlebitis; and (3) great saphenous vein s without varicosity or thrombophlebitis from patients who were undergoing femoropopliteal bypass grafting. The specimens were fixed in 10% neutral bu ffered formalin and embedded in paraffin, and the sections were stained wit h antibodies to S-100 (to identify dendritic cells), CD3 (T-lymphocytes), C D68 (macrophages), von Willebrand factor (endothelial cells), alpha-smooth muscle actin (smooth muscle cells), and CD15 (mast cells) by use of avidin- biotin complex (ABC) immunoperoxidase technique. Immunohistochemical examin ation showed that no S-100-positive dendritic cells were present in normal saphenous veins. In contrast, S-100-positive cells with dendritic cell morp hology were detected in the intima and media of veins with varicosity and t hrombophlebitis, where they represented a minor cell population. S-100-posi tive dendritic cells were located between smooth muscle cells as well as ar ound areas of neovascularization where they colocalized with T-lymphocytes. The present work suggests that dendritic cells might be involved in pathol ogical processes in veins affected by varicosity and thrombophlebitis. The authors speculate that dendritic cells maybe involved in the inflammatory m echanisms in these veins through their interaction with T-lymphocytes.