Abstract: Objective To investigate the expression of Fas antigen and Fas ligand (Fas-L) protein in the skin lesions of patients with lupus erythematosus Methods An immunohistochemical technique was performed for detecting Fas antigen and Fas-L expression in the skin lesions of 25 cases of systemic lupus erythematosus (SLE) and 14 cases of discoid lupus erythematosus (DLE) Results The positive Fas stains were observed in keratinocytes of early skin lesions of both DLE and SLE,and were significantly stronger than those of normal skin (P<0.01),and the expression was negatively related to the course of the disease (P<0.05) Positive Fas stains were also found in mononuclear cells(MNCs) of dermis However,Fas-L was not expressed in keratinocytes in both skin lesions and normal skin of DLE and SLE,only existed in MNCs of dermis in early stage lesions Conclusion The abnormal expression of Fas and Fas-L in keratinocytes and dermal MNCs might be related to the occurrence and development of lupus skin lesions in both DLE and SLE

Key words: Lupus erythematosus,systemic, Lupus erythematosus,discoid, Keratinocytes, Fas