Experimental Studies About Role Of Cytokine In The Pathogenesis Of Graves' Disease

Objective To investigate the concentration of cytokines in serum and the influence of cytokines on apoptosis in thyrocytes from patients with Graves' disease(GD)and study the role of cytokine and apoptosis in the pathogenesis of GD.Method 1.Serum level of IL-6,TNF-α,IFN-γ,FT₃,FT₄ and TSH in 40 untreated and 40 treated GD patients and 39 cases of control were measured by ELISA and CLIA,respectively.2.Thyrocytes from 5 GD patients were cultured in the absence or presence of 1-100U/ml IFN-γand TNF-α,Cell culture viability, Apoptosis and Fas/sFas expression in thyrocytes were assessed by the MTT method,flow cytometry and ELISA.Result 1.Serum level of TNF-α,IFN-γand IL-6 increased significantly in untreated GD group compared with those in normal controls(P＜0.01).Serum level of TNF-αand IFN-γdecreased slightly in treated GD group compared with those in untreated GD group(P＞0.05),but were higher than those in normal controls(P＜0.01).Serum level of IL-6 decreased significantly in treated GD group comparedwith those in untreated GD group(P＜0.01)and wasn't changed compared with those in normal controls(P＞0.05).2.No significant correlation was found between the serum level ofTNF-α,IFN-γ,IL-6 and FT₃,FT₄,TSH in untreated GD group(P＞0.05).3.Cell culture viability was markedly decreased(except for 1U/ml IFN-γP＜0.05)and the level of apoptosis and expression of Fas/sFas were also markedly increased compared with those in control(0U/ml cytokine)by 1-100U/ml IFN-γand TNF-α(except for 1U/ml IFN-γand/or 1U/ml TNF-αP＜0.05).And compared with those in 100U/ml IFN-γand 100U/ml TNF-α,combination of IFN-γwith TNF-αwas markedly decreased in Cell culture viability(P＜0.01)and increased in inducing apoptosis and the expression of Fas/sFas(P＜0.01).4.There was significant correlation between the level of apoptosis and expression of Fas in thyrocytes(P＜0.05).Conclusion 1.The level of TNF-α,IFN-γ,IL-6 of GD group had complicated chang and they might take part in the mechanism of Graves' disease,but they couldn't show severity of pathogenetic condition of GD.2.Though regulating the expression of Fas and sFas,IFN-γand TNF-αcould induce apoptosis in thyrocytes in vitro,cytokines might participate in the regulation of Graves' disease by apoptosis.