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 resi de in the arterial intima and are involved in human atherogenesis. Dur ing the present ultrastructural examination of aortic atherosclerotic lesions, pentalaminal structures, similar to Birbeck granules which un iquely present in Langerhans cells, were found in the cytoplasm of vas cular 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 Langerhan s cells, we used Lag-antibody which specifically stains Birbeck granul es 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 atheroscle rosis. (C) 1997 Elsevier Science Ireland Ltd.