Formation of Birbeck granule-like structures in vascular dendritic cells in human atherosclerotic aorta. Lag-antibody to epidermal Langerhans cells recognizes cells in the aortic wall.

It has previously been demonstrated that vascular dendritic cells reside in the arterial intima and are involved in human atherogenesis. During the present ultrastructural examination of aortic atherosclerotic lesions, pentalaminal structures, similar to Birbeck granules which uniquely present in Langerhans cells, were found in the cytoplasm of vascular dendritic cells and the formation of these Birbeck granule-like structures from dense granules was identified. To find out how Birbeck granule-like structures might relate to Birbeck granules of Langerhans cells, we used Lag-antibody which specifically stains Birbeck granules and Birbeck granule-associated structures in Langerhans cells. Lag-positive cells were found in the aortic wall. Our observations suggest a close relationship between vascular dendritic cells and Langerhans cells and this may imply that mechanisms of antigen presentation known for Langerhans cells might be similar to those involved in atherosclerosis.