Objective To investigate the relationship between serum Th1/Th2 cytokine expression levels and the degree of bone destruction in patients with skeletal tuberculosis.

Methods A total of 75 patients with skeletal tuberculosis admitted from August 2022 to August 2024 were enrolled as the study subjects. Based on varied degree of bone destruction assessed by imaging, the patients were divided into mild bone destruction group (n=51) and severe bone destruction group (n=24). Clinical data of the two groups were compared. Fasting venous blood samples were collected from the patients in the early morning. The levels of Th1 cytokines tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-2 (IL-2)and Th2 cytokinestransforming growth factor-β (TGF-β), interleukin-4 (IL-4), interleukin-10 (IL-10)in the serum were measured using the enzyme-linkedimmunosorbent assay (ELISA). Meanwhile, imaging data such as plain X-rays and magnetic resonance imaging (MRI) were collected to assess the degree of bone destruction. Spearman correlation analysis was used to evaluate the correlation between serum Th1/Th2 cytokine expression and the degree of bone destruction. Multivariate Logistic regression analysis was conducted to identify the influencing factors of the degree of bone destruction in patients with skeletal tuberculosis. The receiver operating characteristic (ROC) curve was employed to analyze the diagnostic efficacy of serum Th1/Th2 cytokines for the degree of bone destruction in patients with skeletal tuberculosis.

Results There were no significant differences in age, gender, body mass index (BMI), and the proportions of patients with a history of hypertension, diabetes mellitus, or hyperlipidemia between the two groups (P>0.05). Compared with the mild bone destruction group, the severe bone destruction group showed significantly elevated serum levels of Th1 cytokines (TNF-α, IFN-γ, IL-2) and significantly decreased serum levels of Th2 cytokines (TGF-β, IL-10) (P < 0.05). Spearman correlation analysis revealed that serum TNF-α (r=0.363, P=0.001), IFN-γ (r=0.383, P < 0.001), and IL-2 (r=0.347, P=0.002) levels were positively correlated with the degree of bone destruction, while serum TGF-β (r=-0.380, P < 0.001) and IL-10 (r=-0.365, P=0.001) levels were negatively correlated with the degree of bone destruction. Logistic regression analysis indicated that TNF-α, IFN-γ, TGF-β, and IL-10 were independent influencing factors for the degree of bone destruction in patients with skeletal tuberculosis (P < 0.05). ROC curve analysis demonstrated that the areas under the curve (AUCs) for TNF-α, IFN-γ, TGF-β, and IL-10 in predicting the degree of bone destruction in patients with skeletal tuberculosis were 0.725, 0.737, 0.735, and 0.726, respectively. The corresponding sensitivities were 62.50%, 75.00%, 62.50%, and 83.33%, and the specificities were 84.31%, 62.75%, 86.27%, and 62.75%, respectively. The combined AUC of these indicators was 0.887, which was superior to that of individual predictions.

Conclusion In patients with skeletal tuberculosis, as the degree of bone destruction increases, the serum levels of TNF-α, IFN-γ, and IL-2 rise, the serum levels of TGF-β and IL-10 gradually decrease. TNF-α, IFN-γ, TGF-β, and IL-10 are independent influencing factors for the degree of bone destruction. Moreover, the combined application of Th1/Th2 cytokines has a certain predictive value for the degree of bone destruction.