Origin and properties of the blister formation factor in blister fluids from recessive dystrophic epidermolysis bullosa.

The origin and properties of the blister formation factor in recessive dystrophic epidermolysis bullosa (RDEB) blister fluids were investigated. Organ cultures of normal human skin incubated with RDEB dermis extract or with RDEB fibroblast culture medium (FCM) produced a clear subepidermal blister with histology similar to that of a RDEB blister in vivo. The injection of RDEB dermis extract into guinea-pig skin also induced dermal-epidermal separation with similar histology to the skin lesions of RDEB patients. The blister forming activity of RDEB FCM which induces the subepidermal blister was inactivated by heat (60 degrees C for 30 min), trypsin digestion and by treating with EDTA, EGTA, alpha 2-macroglobulin, diisopropyl fluorophosphate and N-ethylmaleimide, but was not affected by dialysis. These results suggest that the RDEB fibroblast produces a blister formation factor(s), and that blister formation may be caused by a combination of a metallo-protease, serine protease and SH protease.