Changes in the expression pattern of epidermal stem cell markers in acute and chronic psoriatic lesions

Abstract

Background and Design: The characteristic morphology of skin is maintained by the self-renewal of epidermal stem cells located in the basal layer and in hair follicles in skin diseases. In this study, we tried to determine the pattern of epidermal stem cell location and how it is influenced by hyperproliferative skin disease such as acute and chronic psoriatic lesions. Materials and Methods: Known epidermal stem cell markers such as beta 1 (β1) integrin, cytokeratin 15 (CK15), Melanoma-associates chondroitin sulphate proteoglycan core protein (MCSP), transcription factor (p63) and proliferative factor Ki-67 were stained in normal skin (NS) and in acute/chronic psoriasis for comparison, using immunocytochemistry. Normal skin (n=4), acute (n=5) and chronic (n=5) psoriasis tissue samples were immunostained with monoclonal antibodies against these epidermal stem cell markers. Results: In this preliminary study, β1 integrin and p63 showed strong expression in basal and suprabasal layer of the epidermis in acute psoriatic lesions while basal expressions were detected solely in chronic psoriatic lesions. Weakly positive Ki-67 positive cells in acute lesion were scattered in the basal layer. In chronic lesions, Ki-67 expression was abundant in the basal and adjacent suprabasal layer. CK15 and MCSP are not expressed in all psoriatic lesions. Conclusion: β1 integrin and p63 (+) interfollicular epidermal stem cells especially participate in acute phase of psoriasis while Ki-67 predominates in chronic psoriatic lesions. No role of MCSP and CK15 in pathogenesis of psoriasis has been determined.