Histochemistry XIX. Localization of Alkaline Phosphatase in Normal and Pathological Human Skin.

Abstract

Summary In normal skin, alkaline phosphatase activity was observed in the stratum granulosum, endothelial lining of the capillaries, in hairs, hair follicles, and sweat glands. In the hair follicles, the greatest activity was in the papillae. In the endothelial cells and cells of the sweat glands, the enzyme appears to be concentrated at the cell walls and in the nuclei, the nucleoli showing even greater activity than other parts of the nuclei. Pathologic tissue from cases of lupus erythematosus, psoriasis and papular urticaria showed no significant changes in the enzyme activity. Alkaline phasphatase activity was found in proliferatinq fibroblasts in scar tissue, especially in the newly formtd scar, and also in the fibroblasts and infiltrate of pyogenic granuloma. The nuclei gave a more intense reaction than the cytoplasm of the cells. In chronic eczema of long standing, the cellular perivascular infiltrate of lymphocytes, monocytes and plasma cells, as well as the fibroblasts, showed significant alkaline phosphataae activity. In acne vulgaris, the infiltrate exhibited the enzyme activity.