Histochemistry of the intercellular substance of the normal and psoriatic human epidermis.

The intercellular substance of skin samples obtained from normal subjects and from psoriatic patients has been studied with histochemical methods for carbohydrate containing substances and checked with enzymatic extractions. The surface coat which makes up most of the intercellular substance was stained with colloidal iron and with Alcian Blue solutions containing up to 0.20 M magnesium chloride; the stainings were heavily affected by the previous treatment of the sections with testicular hyaluronidase, but not with neuraminidase. The staining of the intercellular substance with Alcian Blue solutions containing up to 0.20 M magnesium chloride and the action of the hyaluronidase gives strength to the hypothesis that hyaluronic acid is contained in the substance. In the skin of psoriatic patients intercellular spaces wider than in normal skin and a reduced surface coat, particularly in the higher layers, has been observed.