Abstract:AIM: To investigate the correlation of serum interleukin-35(IL-35), immunoglobulin 4/immunoglobulin(IgG4/IgG), thyroid stimulating immunoglobulin(TSI)levels with the activity and severity of thyroid associated ophthalmopathy(TAO).METHODS:Prospective study. A total of 148 TAO patients admitted to our hospital from January 2023 to July 2024 were selected as the observation group. They were assigned into an active group(75 cases)and an inactive group(73 cases)based on their activity level, and were assigned into a severe group(95 cases)and a mild group(53 cases)based on the severity of their condition; another 148 healthy patients who underwent physical examinations were regarded as the control group. The levels of IL-35, IgG4/IgG, and TSI in serum were compared between the two groups. The correlation between serum IL-35, IgG4/IgG, and TSI levels and TAO activity and severity of illness were analyzed. A multivariate Logistic regression was performed to analyze the influencing factors of TAO patients developing severe symptoms. ROC curve was applied to analyze the diagnostic value of serum IL-35, IgG4/IgG, and TSI levels for the development of severe TAO in patients.RESULTS: Compared with the control group, the serum IL-35 level in the observation group was significantly lower, while IgG4/IgG and TSI levels were significantly higher(all P<0.01). Compared with non-active TAO patients, active TAO patients had significantly lower serum IL-35 level and significantly higher IgG4/IgG and TSI levels(all P<0.01). Compared with the mild TAO patients, severe TAO patients had significantly lower serum IL-35 level and significantly higher disease duration, IgG4/IgG, and TSI levels(all P<0.01). The serum IL-35 level was negatively correlated with TAO activity and disease severity(r=-0.529, -0.554, both P<0.01), while serum IgG4/IgG level was positively correlated with TAO activity and disease severity(r=0.625, 0.663, both P<0.01). Serum TSI levels were positively correlated with TAO activity and disease severity(r=0.594, 0.607, both P<0.01). Multivariate Logistic regression analysis showed that serum IL-35, IgG4/IgG, and TSI levels were all factors influencing the progression of TAO patients to severe disease(all P<0.01). The areas under the curve(AUC)for diagnosing the progression of TAO patients to severe disease using serum IL-35, IgG4/IgG, and TSI levels were 0.868, 0.859, and 0.830, respectively. The combined AUC for the three markers was 0.955, significantly higher than that of each individual marker(Zthree factors combination-IL-35=2.893, Zthree factors combination-IL-35=3.510, Zthree factors combination-IL-35=4.157, P=0.004, <0.01, <0.01).CONCLUSION: Serum IL-35 level is significantly downregulated in TAO patients, while IgG4/IgG and TSI levels are significantly upregulated. The levels of IL-35, IgG4/IgG, and TSI are correlated with the activity and severity of TAO, and their combination has high diagnostic value for TAO developing into severe.
