Abstract: Objective To investigate the role of costimulatory molecules CD28/B7 in the pathogenesis of psoriasis. Methods The expression of CD28, CD80 and CD86 was detected in the lesional skin of 22 cases by immunohistochemical technique (ABC), and in the peripheral blood lymphocytes of 17 cases by flow cytometry respectively. As control, normal skin and lymphocytes from peripheral blood of healthy volunteers were also tested. Results The immunohistochemistry study showed that the expression of CD28, CD80 and CD86 in the psoriatic lesions was significantly higher than that in the normal controls (P<0.01). Comparing with the lesions of stable stage the expression was higher in the lesions progressive stage (P<0.05). According to the results of flow cytometry, the expression of CD28, CD80 and CD86 on the lymphocytes of psoriasis was significantly higher than that in the normal controls (P<0.01); comparing the lesions of two stages significantly higher expression of CD80 and CD86 was found in the lesions of progressive stage respectively (P<0.01, P<0.05), but no difference for CD28 (P>0.05). Conclusion CD28, CD80 and CD86 might play a certain role in the pathogenesis in psoriasis.

Key words: Psoriasis, Antigens, CD28, Antigens, CD80, Antigens, CD86