BACKGROUND: Cytokeratins (K) are the major structural proteins of epithelial cells and they display the greatest heterogeneity of all intermediate filament proteins. The study of many isolated cytokeratins by immunomarcation enables the structural verification of the cytoskeleton in many neoplastic and inflammatory diseases. OBJECTIVE: To verify the immunohistochemical pattern of cytokeratin expression in infectious and parasitic diseases associated with squamous hyperplasia. METHODS: Histological sections obtained from formalin-fixed and paraffin-embedded tissue from cromomycosis, paracoccidioidomycosis, leishmaniasis and condylomata acuminata lesions were marked with the DEK10, LL025, LL002 and AE1 antibodies by the immunoperoxidase technique (avidina-botina). RESULTS: Different degrees of epidermal hyperplasia were observed predominantly or exclusively in the following four diseases: absence of immunoreactivity to DE-K10 in areas of intense epidermal hyperplasia and delayed K10 immunohistochemical staining in areas of moderate to discreet/absent hyperplasia; superbasal expression pattern for K16, regardless of the degree of hyperplasia as well as superbasal epitops discharging for LL002 (C14) and AE1 (C10, 14, 16, 19). CONCLUSIONS: The modifications indicate that regardless of the nature of the etiologic agent and degree of hyperplasia, changes in keratinocyte differentiation and proliferation may occur.
epidermis; hyperplasia; keratin
