Circular and branched Birbeck granules and cytomembrane blebbing in Langerhans´ cells after dithranol irritation
Mild dithranol irritation of healthy human skin has a stronger effect on the fine structure of Langerhans´ cells (LC) than on that of other epidermal cells, causing mitochondrial enlargement and disruption of the cristae of LCs. With a stronger dithranol irritation, LCs were even more affected resulting in circular and branched Birbeck granules (BG) and blebbing of the LC cytomembrane. More often than is normal, BGs were contiguous with the LC cytomembrane. Electron microscopic observations indicated that blebbing and the abnormal BG formation were associated phenomena, in accordance with the hypothesis that BGs are endocytotic organelles formed from the cytomembrane.