Pemphigus serum-induced loss of microvilli from human epidermal cells.

Scanning electron microscopic examination of human epidermal cells prepared from suction blister roofs by treatment with trypsin and dithioerythritol and incubated (37 degrees C, 18 hours) with pemphigus sera revealed a smooth or wrinkled surface texture in 83 to 96% and surface microvilli in only 17 to 4%. The disappearance of microvilli was not affected by the presence of complement. In the control specimen 54% of the cells retained their microvilli. The difference between cells incubated with pemphigus and those incubated with control sera was highly significant (p less than 0.001). Epidermal cell suspensions were also incubated with pemphigus vulgaris sera plus a protease inhibitor (ovomucoid). The loss of microvilli from human epidermal cells induced by pemphigus vulgaris serum was highly significantly inhibited by ovomucoid (p less than 0.001). The results suggest that the loss of microvilli induced by pemphigus sera, irrespective of the presence of complement, may be an important factor in acantholysis of pemphigus. Proteolytic enzymes may be responsible for the loss of microvilli and smoothing of the cell surface of human epidermal cells in vitro.