Histochemical study of Erythema nodosum leprosum (ENL) lesions.

A histochemical study of ENL lesions was performed on skin biopsies from 14 leproma-tous patients. There was: 1) the presence of moderate amounts of PAS positive diastase resistant materials, acid mucopolysaccharide, neutral fat, phospholipid, aryl sulfatase and acid phosphatase in areas around and away from reactional sites; 2) the presence of slight amounts or complete absence of these materials within areas of acute inflammation. These changes were interpreted as the result of solubilization and leakage of hydrolytic enzymes into the surrounding tissue. A possible role of lysosomal enzymes in the pathogenesis of ENL lesions is discussed.