Studies On Association Of Tumor Necrosis Factor-α And Its Receptors In Skin Lesion Biopsies And Sera From Patients With Psoriasis Vulgaris

PREFACEPsoriasis is characterized by hyperproliferation of epidermis keratinocytes and infiltration of lymphocytes. Immunological abnormabilities which are regulated mainly by interaction among cytokines play an important role in the onset of psoriasis. It is reported that TNF -a (an important cytokine in the pathogenesis of psoriasis) and its receptors are expressed abnormally in psoriatic lesion and / or peripheral blood.It is showed that the immunoreaction and biological activity of TNF - a elevated significantly in psoriatic lesion. And there is a large quantity of TNF - a in supernatant of psoriatic lesion in the course of its frozening and melting. Overexpression of TNF - a on adhersive molecular on keratinocytes, vascular en-dothelial cells and epidermal dendritic cells suggested that TNF - a may play a role in the immunological pathogenesis of psoriasis by interfering expression of adhesion mollecular in psoriatic lesion. But TNF - a can not be detected steadly in psoriatic lesions.TNF - a could produce its biological effect only if it combined with its receptor. It was reported that both the whole layer of psoriatic lesional epidermis and infiltrating cells around blood vessel in psoriatic lesional dermis expressed TNFR - I , and was considered that TNF - a affected keratinocytes through coombining with TNFR - I . There was no expression of TNFR - II in psoriatic lesion, but expression of TNFR - II on infiltrating cells in dermis was observed. Further study found that both content of TNFR - I and that of TNFR - II in-creased obviously in psoriasis lesions, considering that the releasing systemic ot locally of TNF - a receptor may regulate the effect of TNF - a. It is obvious that the expression of TNFR - I and TNFR - II was not clear in psoriasis lesion. There was no domestic report about the expression of TNF - a and its receptors in uninvolved skin adjacent to the lesions.It had been studied recently whether there was abnormal expression of TNF - a and its receptors or not in peripheral blood of patient with psoriasis. Gomi didnt detect TNF - a in sera of 21 cases with psoriasis vulgaris . The following research showed the content of TNF - a elevated significantly in peripheral blood of psoriasis patients. Lastly some researchers also found the content of TNF -am sera increased in their studying on relationship between cytomegalovirus infection and TNF - a. The results mentioned above suggested that TNF - ounay be involved in the pathogenesis of psoriasis.The soluble TNF - a receptors ( sTNFRs ) in peripheral blood played an important role in regulating the biological activity of TNF - a. But reports was few about the relationship between sTNFRs and psoriasis. Recent research indicated that sTNFRs content of sera in patients with psoriasis increased obviously; Other studies showed TNF - a content reduced and the activity of sTNFR - I and sT-NFR - II was upregulated in sera of patients with psoriasis arthropathica, sTN-FRs which was involved in immunoregulation and reflected the activity of immune cells had close relationship to other soluble immune substances ( sIL -2R). It was important to detect TNF - a and its receptors in psoriasis lesion and peripheral blood simultaneously for evaluating the change of TNF - a and its receptors. But there was no report in this aspect until now.Therefore, the expression of TNF - a and its receptors in psoriatic lesions and uninvolved skin adjacent to the lesions was investigated by immunohisto-chemistry technique. TNF - a and its receptor in sera of patients with psoriasis were also detected by EIISA in order to explore the possible role of TNF - a and its receptor in the pathogenesis of psoriasis. There was no report domestic and a-broad whether TNF - a and its receptors mRNA expressed or not in epidermis of psoriasis lesion, the relative quantity of TNF - a and its receptors mRNA in pso-riatic epidermis was also detected by RT - PCR so as to explore the effect of TNF - a and its receptors mRNA on the pathogenesis of psoriasis vulgaris.