The expression of vascular dendritic cells in human atherosclerotic carotid plaques.

Atherosclerosis is currently considered a chronic inflammatory disease, and evidence is accumulating for a role of the immune system in the progression of atherosclerosis. Dendritic cells are specialized antigen-presenting cells with the unique ability to initiate a primary immune response to certain antigens by the activation of naive T-lymphocytes. Although dendritic cells are well known to be important in the development of different diseases, studies of vascular dendritic cells in atherosclerosis are rare, and their role is not clearly understood. Therefore, we investigated the immunohistochemical expression of vascular dendritic cells in atherosclerotic plaques. Between April 2003 and December 2005, carotid endarterectomy was performed in 26 consecutive patients, and 27 carotid plaque specimens were analyzed. We investigated the immunohistochemical expression of vascular dendritic cells in human carotid plaques by measuring the signal intensity of fascin-positive cells using an image analyzer. In addition, these immunohistochemical results were related to clinical data. The highest signal intensity of dendritic cells was found in plaque shoulders, and the mean signal intensity of dendritic cells was significantly higher in complicated than in uncomplicated plaques (P = .0029). Moreover, the mean signal intensity of dendritic cells in plaques from symptomatic patients was significantly elevated compared with plaques from asymptomatic patients (P = .0004). Although atherosclerotic plaque instability is determined by multiple factors, the immune and inflammatory pathways play a particularly important role. Dendritic cells play a role in atherosclerosis, and the present study suggests that the expression of dendritic cells in human carotid arteries may be strongly associated with the occurrence of ischemic stroke.