To evaluate the change trend of serum interferon-γ (IFN-γ) level during pulmonary tuberculosis treatment, to explore the possible influencing factors, and to provide evidences for the significance of serum IFN-γ level monitoring in the course of pulmonary tuberculosis treatment.

The serum of 56 patients with pulmonary tuberculosis treated at Guangzhou Chest Hospital from September 2020 to December 2022 was collected and measured by flow cytometry before the treatment and after 2 and 6 months' treatment. The measurement data not of normal distribution were compared by Kruskal-Wallis and Mann-Whitney tests. Friedman test was used for the paired samples.

The serum concentration of IFN-γ in the patients with pulmonary tuberculosis decreased during the treatment, with a statistical difference (P=0.004). Before the treatment, the serum concentration of IFN-γ in the patients with pulmonary cavity was higher than that in the patients without pulmonary cavity, with a statistical difference. When the serum concentration of IFN-γ was used to distinguish between before and 2 months after the treatment and between before and 6 months after the treatment, the areas under receiver operating characteristic curves (ROC) were 0.582 and 0.646; the cut-off values were 1.520 and 2.345 ng/L; the sensitivities were 91.10% and 44.60%; the specificities were 32.10% and 69.60%. Binary logistic regression analysis showed that whether serum IFN-γ concentration fell below 1.520 ng/L after 2 months' treatment was related to whether the patients had diabetes. When the enrolled cases were limited to the positive etiopathogenesis before the treatment and when the serum concentration of IFN-γ was used to distinguish between before and 2 months after the treatment and between before and 6 months after the treatment, the areas under ROC were 0.762 and 0.770; the cut-off values were 1.725 and 1.705 ng/L; the sensitivities both were 93.75%; the specificities both were 50.00%.

The concentration of serum IFN-γ before pulmonary tuberculosis treatment is related to whether or not there is a cavity in the lungs, and the overall trend of decrease during the treatment is related to whether the patients are complicated with diabetes and the patients' etiological results before treatment.

Tuberculosis; Treatment process; Serum; IFN-γ