Immunofluorescence studies on epidermal keratinization in some skin disorders with keratin antisera

The immunofluorescence technique using antisera against human plantar stratum corneum fibrous protein (total keratin) and 64K M.W. keratin subunit isolated from total keratin by SDS polyacrylamide gel electrophoresis (PAGE) was used to examine epidermal keratinization in some skin disorders. In normal skin, total keratin was distributed throughout the epidermis, while 64K keratin was localized at the suprabasal layers. In the case of squamous cell carcinoma (SCC), the tumor cells were uniformly stained positive with total keratin antiserum, whereas diminished or negatively stained cells were observed with 64K keratin antiserum (64K antiserum), suggesting that the tumor included cells in various stages of differentiation. In basal cell epithelioma (BCE), most of the tumor cells were negatively stained with 64K antiserum being consistent with the histologic observation that BCE is originated from the basal cells. However, some of the tumor cells were stained positive with 64K antiserum, indicating that individual cell keratinization might occur in BCE. In lichen planus, an inflammatory disease demonstrating so-called lichnoid tissue reaction, positively stained colloid bodies in the upper dermis were observed either with total keratin antiserum or with 64K antiserum. It was suggested that colloid bodies resulted from individual keratinization of damaged keratinocytes during inflammation.