The use of monoclonal antibody to keratin in human epidermal disease: alterations in immunohistochemical staining pattern.

A monoclonal antikeratin antibody, designated AEl, was used to stain frozen sections of normal and abnormal human skin by the immunofluorescence and peroxidase-antiperoxidase techniques. In normal human epidermis and ichthyosis vulgaris, a nonproliferative epidermal disease, this antibody selectively stained epidermal basal cells. Very different staining patterns were observed in various other epidermal diseases. A suprabasal staining pattern was observed in psoriasis (16 cases), verruca (9), seborrheic keratosis (5), actinic keratosis (2), as well as the epidermis adjacent to certain epidermal neoplasms (4). Basal cell carcinoma (7) showed weak, homogeneous staining. In contrast, a disorganized pattern consisting of cells with various staining intensities was observed in Bowen's disease (2) and squamous cell carcinoma (4). Although the biochemical basis for these altered staining patterns remains to be elucidated, these results provide further evidence that epidermal keratin expression can be affected by various disease states. Moreover, our data suggest that a common alteration in keratin expression, as defined by the suprabasal AEl staining pattern, exists in psoriasis and a number of other benign hyperproliferative epidermal diseases.