The hereditary forms of ichthyosis can be considered to be models of impaired terminal epidermal differentiation. Analysis of the cytokeratin polypeptide pattern represents a new attempt at elucidating the mechanisms of keratinization mechanisms which are still unclear. We therefore studied the cytokeratin expression of the following types of ichthyosis: autosomal dominant ichthyosis vulgaris (n = 4), X-linked recessive ichthyosis vulgaris (n = 4), recessive non-bullous congenital ichthyosiform erythroderma (n = 1), recessive classical lamellar ichthyosis (n = 2), autosomal dominant lamellar ichthyosis (n = 1), and Netherton syndrome (n = 1). After dissection of frozen sections of the interfollicular epidermis, two-dimensional gel electrophoresis was performed. For immunofluorescence microscopy a panel of monoclonal cytokeratin antibodies (KG8.13, KK8.60, KA5 and AE1) was used. Cytokeratin polypeptide expression was basically unchanged compared with normal epidermis. In contrast, however, the antibody AE1 did not stain the basal cell layer in most types of ichthyosis, regardless of their genetic type. The cytokeratin polypeptides nos. 6 and 16, which are generally considered markers of hyperproliferation, were not expressed in either type of ichthyosis vulgaris (XRI or ADI), but were detected in trace amounts in various types of congenital ichthyosis.
