Abstract: Objective To study the mechanism of tumor necrosis factor(TNF) α in psoriasis vulgaris. Methods The expressions of 55-kD(p55) and 75-kD(p75) TNF receptors, intercellular adhesion molecule(ICAM)-1, lymphocyte function associated antigen(LFA)-1 in the lesional skin of psoriasis vulgaris were detected by immunohistochemical method. Results Normal skin did not express p55, p75, ICAM-1 and LFA-1, the epidermis of the lesional skin expressed p55, p75 and ICAM-1, the infiltrating mononuclear cells (MNCs) in the dermis expressed p55, p75 and LFA-1 in psoriasis vulgaris. The intensities of staining of the p55 and ICAM-1 on epidermal keratinocytes(EKC) were significantly correlated (r'_s=0.704, P<0.05), but p75 and ICAM-1 were not correlated (r'_s=0.589, P>0.05). The staining intensity of ICAM-1 on EKC and the number of infiltrating MNCs in the dermis was significantly correlated (r'_s=0.724, P<0.05) in psoriasis vulgaris. Conclusion TNFα may induce the expression of ICAM-1 on KC through the mediation of p55 and ICAM-1 induces the infiltration of MNCs in the dermis, which promotes the development and progression of psoriasis vulgaris.

Key words: Psoriasis, Receptors,tumor necrosis factor, Intercellular adhesion molecule-1, Antigen,lymphocyte function associated；