Fas (CD95) and bcl-2 expression in active skin lesions of Behçet's disease.

Over-expression of bcl-2 in lymphocytes has an important role in some immunological and inflammatory diseases. Fas (CD95) is a cell surface molecule that mediates receptor-triggered apoptosis in various cells including autoreactive T cells. In this study we investigated bcl-2 and Fas (CD95) expression in dermal lymphocytes in active skin lesions of Behçet's disease (BD) and in skin biopsy samples with chronic, non-specific inflammations. Tissue sections of 29 skin lesions of Behçet's disease and of 10 chronic non-specific inflammatory process cases from the archives of the Ondokuz Mayis University's Pathology Department were immunohistochemically stained for bcl-2 and Fas (CD95), and lymphocytes in the dermal infiltrate were evaluated for cytoplasmic staining. bcl-2 staining was observed in the skin lesions of 22 cases (75.8%) of Behçet's disease. bcl-2 staining was detected in two (20%) control skin biopsy samples with non-specific chronic inflammation. Fas (CD95) positivity was not detected in lymphocytes in Behçet's disease-related skin lesions. Fas (CD95) staining was observed in only three skin biopsy samples with non-specific chronic inflammation. bcl-2 and Fas (CD95) staining values in Behçet's and non-specific inflammation groups were significantly different (P < 0.01); differences in the bcl-2 staining values between Behçet's patients with mucocutaneous involvement only and mucocutaneous and other systemic involvements were not significant (P > 0.05). Expression of bcl-2 and loss of Fas (CD95) expression in dermal lymphocytes may play a role in the development of skin lesions and may account for the chronic course with periodic exacerbations in BD.