Role of IFN-γ, IL-33, and IL-35 concentrations in tuberculous pleural effusion in diagnosis and analysis of the effectiveness of combined tests

Abstract

This study examines the diagnostic utility of the combined interleukin-33 (IL-33), interferon-γ (IFN-γ), and interleukin-35 (IL-35) test in tuberculous pleural effusion. Forty patients with pleural effusion of unknown etiology admitted to the hospital between December 2020 and December 2023 were selected as the study group. The patients were further categorized into tuberculous (TB) (n = 20) and malignant (n = 20) groups on the basis of their relevant data, while sera from 20 healthy medical checkups were used as control group. Thoracentesis was used to collect pleural fluid, and after its collection, enzyme-linked immunosorbent assay was utilized to detect the concentration content of IL-35, IL-33, and IFN-γ in pleural fluid of patients with different types of diseases. Data processing and analysis were executed through SPSS23.0 software to plot the receiver operating characteristic curve and compare the area of the area under the line of each index. Adenosine deaminase level was statistically higher in TB group patients (59.91 U/L) than in malignant group (14.31 U/L) (P < .05). Pleural fluid lactate dehydrogenase levels did not differ significantly between the 2 groups (P > .05). T-SPOT test had a higher positive rate in the TB group (85%) and a lower positive rate in the malignant group (45%). The TB group exhibited significantly higher levels of IFN-γ expression than the malignant group (P < .05). The TB group had higher levels of IL-33 and IL-35 compared to the malignant group, with a statistically significant difference (P < .05). The TB group had a greater level of IL-33 (81.05 ± 10.11 pg/mL) than the cytology-positive group (39.37 ± 9.63 pg/mL), while the difference was not statistically significant (P > .05). The level of IL-35 (70.11 ± 10.37 pg/mL) in the TB group was lower than the level of IL-35 (72.13 ± 9.58 pg/mL) in the cytology-positive group. The specificity of the series of combined tests reached 95.81%, which was statistically superior to the single-factor test (P < .05). In the TB group, IFN-γ and IL-33, IFN-γ and IL-35, and IL-33 and IL-35 showed positive correlation. Combined determination of the concentration levels of IL-35, IL-33, and IFN-γ is of value in the diagnosis of tuberculous pleurisy.