[Ultrastructural changes of capillaries by UV in psoriatic lesions (author's transl)].

The structure of capillaries is examined with the electron microscope in patients who were treated by UVB (long wave part, selected ultraviolet therapy-SUP). Chronic degenerative changes were observed in the capillary walls and the nearest surroundings, but these changes are not specific for ultraviolet injury. Even when endothelial cells become necrotic, the capillary walls are not destroyed, and therefore a direct communication between lumen and extravasal space is not to be seen. These alterations suppress the psoriatic hyperproliferation.