CD40 co-stimulatory molecule expression by dendritic cells in primary atherosclerotic lesions in carotid arteries and in stenotic saphenous vein coronary artery grafts

We have previously identified dendritic cells in the intima of human large arteries and stenotic vein coronary bypass grafts. The mechanisms by which these dendritic cells might regulate immune responses in atherosclerotic le sions and stenotic vein grafts are unknown. The aim of the present study wa s to investigate whether dendritic cells in carotid plaques and in stenotic aortocoronary vein grafts express an immunoregulatory molecule CD40. Segments of wall from eight carotid arteries and three stenotic aortocorona ry saphenous vein grafts were obtained at operation. CD40(+) cells were det ected in all specimens of both occluded and stenotic grafts and carotid pla ques. Although CD40(+) cells of various cell types were intermingled in mos t areas within the plaques and stenotic grafts, there were sites where CD40 (+) cells were located in small groups. Consecutive sections demonstrated t hat a small population of CD40(+) cells stained positively for S100. These CD40(+)/S100(+) cells were clustered within the intima but were also found in the media and adventitia. This suggests that dendritic cells, which accu mulate within vessels affected by atherosclerosis and graft disease, expres s CD40 co-stimulatory molecule. The expression of CD40 molecule on the dend ritic cells may be important in regulating T cell responses within atherosc lerotic plaques and stenotic vein grafts. (C) 2001 The International Societ y for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved.