Expression Of Serum TNF-alpha, IL-4 And IL-6 In Autoimmune Thyroid Disease

To investigate the expression of tumor necrosis factors alpha (TNF-alpha), interleukin-4 (IL-4) and IL-6 in serum in patients with autoimmune thyroid disease (AITD) and the role of the serum cytokine in the immunoreaction.Methods: serum tumor necrosis factors alpha (TNF-alpha), interleukin-4 (IL-4),IL-6,thyroid hormone and correlative antibody of thyroid were determined in 66 patients with Graves' disease (GD) without ophthalmopathy (45 cases untreated, GDâ… group; 21 cases treated, GDâ…¡group),33 patients with Hashimoto's thyroiditis (HT),35 patients with Graves' ophthalmopathy(GO) and 36 control cases. The level of TNF- alpha,IL-6,IL-4,TgAb and TmAb were determined by radioimmunoassay(RIA). The level of total T3 (TT3),total T4 (TT4) and thyrotropin hormone (TSH) were examined with chemiluminescent immunoassay.Results: Compared with the control,the level of TNF- alpha,IL-6 and IL-4 were significantly elevated in GD,HT and GO (P<0.05,P<0.01).In GDâ… group,IL-4 level was significantly higher than that in other groups (P<0.01), TNF- alpha / IL-4 ratio decreased compared with control group (P<0.05),IL-6 level was not changed significantly compared with HT group (P>0.05).In GDâ…¡group, the level of IL-4 was significantly lower than that in GDâ… group (P<0.01). In GO groups, the level of IL-6 increased significantly compared with GD group and HT group (P<0.05,P<0.01), TNF- alpha level was significantly higher than that in GD group (P<0.05), IL-4 level was significantly deceased compared with GDâ… group (P<0.01). In HT group, TNF- alpha level increased significantly compared with GD group (P<0.01), IL-4 level was significantly lower than that in other groups (P<0.05,P<0.01),TNF- alpha / IL-4 ratio significantly increased compared with GD group(P<0.01) and control group (P<0.05).The level of TNF- alpha and TNF- alpha / IL-4 ratio were positively correlated with TgAb and TmAb (all P<0.01).Conclusions: TNF-alpha, IL-4 and IL-6 are involved in the pathogenesis of AITD.The manifestation of IL-4 overexpression indicated a predominant Th2 mediated humoral immunity in GD without ophthalmopathy. In GO patients, TNF-alpha produced from Th1 and IL-6 produced from Th 2 increased suggesting Th0-like immune responses may play a role in the development of GO.The manifestation of TNF-alpha overexpression indicated a predominant Th1 mediated cell immunity in HT.