Cytoplasmic differentiation antigens of human epidermal cells.

Three immunologically distinct types of cytoplasmic antigens have been found to be expressed concurrently in normal human skin. These antigens are tissue but not species specific and differ by their location in different subpopulations of cells. One type is present only in the superficial layers of the epidermis, another only in basal cells, and the third is present in all keratinocytes. All subjects studied to date have all three types of antigens in their skin. There seems to be two subgroups of antigens of each type. One subgroup consists of antigens expressed universally in all subjects. The other consists of a family of variably expressed antigens which are common to some but not all persons. They may represent genetically determined alloantigens different from HLA. The superficial basal cell antigens are absent or greatly decreased in expression in malignant, but not in benign, tumors of the epidermis. This finding, along with the stratification of the antigens in different layers of the skin, suggests that epidermal cytoplasmic antigens are differentiation antigens.