Epithelial and mesenchymal markers in SSc skin.

<p>(A) Representative images of double immunofluorescent staining of forearm skin sections performed to detect basement membrane protein collagen IV (red) and mesenchymal cell marker FSP-1 (green). The basement membrane collagen IV was not seen to be compromised in SSc, whereas some abnormal expression of FSP-1 in keratinocytes was seen in the SSc sections. (B) Additional stains for E-cadherin (green) and vimentin (red) were performed showing no loss of E-cadherin in SSc epidermal cells. Some expression of vimentin was however observed in the SSc epidermis. (C)Further analysis of FSP-1 positive cells was confirmed, since Langerhans cells within the epidermis are known to stain positive for mesenchymal markers. Immunostaining for FSP-1 (green) and Langerin (red) revealed that at least some of the FSP-1 positive cells were indeed from the Langerhans cell population (double positive cells shown with arrow). (BM = basement membrane, BV = blood vessels).