Abstract：
Elevated immunoglobulin G4 (IgG4) serum antibodies are an important feature of IgG4-related disease. However, IgG4 antibodies can play a role in autoimmune thyroid disorders. In this study, we aimed to evaluate the impact of serum IgG4 levels on clinical features of Graves\' disease (GD). We recruited 60 patients with GD (48 patients without thyroid eye disease, 12 patients with moderate-to-severe Graves\' orbitopathy [GO], and 25 healthy control subjects). The prevalence of high IgG4 serum concentration was 4.2% among GD patients without GO and 33.33% in patients with moderate-to-severe GO. The group with GO had significantly higher median IgG4 levels (87.9 mg/dL) than the control group (41.2 mg/dL, P = 0.034) and the GD without GO group (30.75 mg/dL, P < 0.001). Patients with thyroid nodules had lower IgG4 levels than patients without thyroid nodules, but the difference was not statistically significant (35.7 [24.8; 41.53] mg/dL vs. 43 [30.1; 92.7] mg/dL, P = 0.064). IgG4 as a diagnostic tool for moderate-to-severe GO had the following parameters: area under the curve (AUC): 0.851 (P < 0.001), at the cut-off value of 49 mg/dL, negative predictive value: 100%, positive predictive value: 48%, sensitivity: 100%, specificity: 73%. There were no significant differences between the high and normal IgG4 groups in thyroid hormones, antithyroid antibodies, and ultrasound features. Serum IgG4 levels are associated with some of the clinical features of GD and can help in the diagnostic process of the disease. More research is needed to better understand the pathophysiology of IgG4 involvement in GD.
摘要：
免疫球蛋白G4(IgG4)血清抗体升高是IgG4相关疾病的重要特征。然而,IgG4抗体可以在自身免疫性甲状腺疾病中发挥作用。在这项研究中,我们旨在评估血清IgG4水平对Graves病(GD)临床特征的影响。我们招募了60例GD患者（48例无甲状腺眼病，12例中度至重度Graves眼眶病[GO]，和25名健康对照受试者)。在无GO的GD患者中，高IgG4血清浓度的患病率为4.2%，在有中重度GO的患者中为33.33%。GO组的中位IgG4水平（87.9mg/dL）明显高于对照组（41.2mg/dL，P=0.034）和GD无GO组（30.75mg/dL，P<0.001)。甲状腺结节患者的IgG4水平低于无甲状腺结节患者，但差异无统计学意义(35.7[24.8;41.53]mg/dLvs.43[30.1;92.7]mg/dL,P=0.064)。IgG4作为中度至重度GO的诊断工具具有以下参数：曲线下面积（AUC）：0.851（P<0.001），在49mg/dL的临界值下，阴性预测值：100%，阳性预测值：48%，灵敏度:100%,特异性：73%。高和正常组的甲状腺激素IgG4无显著差异，抗甲状腺抗体，和超声特征。血清IgG4水平与GD的一些临床特征有关，可以帮助疾病的诊断过程。需要更多的研究来更好地了解IgG4参与GD的病理生理学。
