Detection Of CD4～+CD25～+Tr Cell And Fas/CD95 Antigen In Peripheral Blood Mononuclear Cells And Its Significance In The Patients With Behcet's Disease

Background: Beliefs disease(BD) is a multisystem disorder of unknown origin with the histopathological correlate of a leucocytoclastic vasculitis. It is characterized by recurrent oral and/or genital aphthous ulcers, skin lesions and ocular lesions, joints, lungs, the central nervous system, cardiovascular system and gastrointestinal tract can be also involved.Recent studies have revealed the central role of T cell mediated immune response in the pathogenesis of BD. CD4~+CD25~+Tr is an important immunocyte which can depress the activation and multiplication of immunocompetence cells, Fas (CD95) is a cell surface molecule that mediates receptor-triggered apoptosis in various cells including auto reactive T cells. Although the detail mechanism has not been known completely yet, it do play an important role in modulating the balance of immunity state.Objective: To investigate the percentages of CD4~+CD25~+Tr cell and the expression of Fas/CD95 in peripheral blood mononuclear cells from patients with Behcet's disease and to study their correlation with the activity of the disease.Methods: PBMC were stained with monoclonal antibodies, the proportion of peripheral blood CD4~+CD25~+Tr and Fas/CD95 was measured by flow cytometry in 31 patients with BD and 27 healthy volunteers serves as control. CellQuest software and SPSS11.0 were employed for statistical analysis. Results: The proportion of CD4~+CD25~+Tr in patients with active BD (6.43%±2.54%) was lower than that of the healthy controls (8.17%±2.87%) (P<0.05), whilepatients who with inactive BD (8.35% ±2.31%) was higher than the healthycontrols(P>0.05). The expression of Fas/CD95 in active BD is lower than that of thehealth controls(P<0.05).Conclusions :① The reduced percentage of CD4~+CD25~+/CD4~+ in BD may correlatedwith the disease's activity. ②Loss of Fas (CD95) expression in peripheral bloodmononuclear cells may account for the chronic course with periodic exacerbations inBD.③It is a feasible method to evaluate the patient's immunologic state by measuringthe proportion of CD4~+CD25~+Tr in peripheral blood lymphocytes.