Immunohistochemical study on pigmented nevi (preliminary communication).

: The human ABH blood-group antigen expression of cytokeratin, S-100 protein, and the melanoma-associated antigen was studied in 12 cases of pigmented nevi. The biotin-streptavidin immunostaining system was applied. ABH antigens were found both in the endothelial cells and in the germinative epidermal layer. The flat overlaying epithelium, single melanocytes and melanoblasts were positive for cytokeratin. Some basilar cells and the giant multinucleate cells in the Spitz nevi stained for S-100 protein. The melanoma-associated antigen was visualized in the upper epidermal layers as well as in some melanocytes. The present article discusses the specificity of the antigens studied as well as some immunologic traits of potential malignant development of Spitz nevi.