Collagenase and Connective Tissue Metabolism in Epidermolysis Bullosa

Ninteen patients with various types of epidermolysis bullosa were studied for evidence of increased collagen catabolism. Cultures of clinically normal but pathologically blisterable skin from nine patients with dermolytic bullous dermatoses, four patients with epidermolysis bullosa simplex and two patients with junctional bullous dermatoses did not differ significantly in collagenase production. In two patients with dermolytic bullous dermatoses cultures of skin lesions produced three times more collagenase and had twice the DNA content of adjacent normal appearing but pathologically blisterable skin. Two of the nine patients with dermolytic bullous dermatoses had minimally decreased levels of serum collagenase inhibitor. None of the patients had increased hydroxyproline excretion in the urine. Four of six patients with dermolytic bullous dermatoses and one of two patients with junctional bullous dermatoses had anti-denatured collagen antibodies. It appears that increased local levels of collagenase are a secondary tissue reaction to chronic injury