Abstract:

Objective: To evaluate the clinical value of Mycobacterium tuberculosis (MTB)-specific antigens-induced cytokines in the diagnosis of tuberculosis in HIV-infected individuals. Methods: A total of 132 HIV-infected individuals who visited Beijing Ditan Hospital and Beijing You’an Hospital from December 2021 to June 2024 were prospectively included as study subjects. Twelve milliliters of peripheral blood were collected from each patient, and the interferon-γ release assays were performed on peripheral blood. The whole blood with or without MTB-specific antigens stimulation was collected and the total RNA was extracted automatically, and then the expression levels of cytokines (interleukin-2 (IL-2), IL-5, IL-18, IL-24, monocyte chemoattractant protein-1 (MCP-1), MCP-2, MCP-3, chemokine CXC ligand 9 (CXCL9), chemokine CXC ligand 10 (CXCL10), CC motif chemokine ligand 19 (CCL19), macrophage colony-stimulating factor (CSF-1), and interferon-γ (IFNG)) were tested by SYBG-qPCR. The differences in the expression level of cytokines were analyzed between the TB group and the non-TB group, and the performance of cytokines in differentiating TB was investigated by receiver operating curve (ROC) analysis. Lasso analysis was also performed to evaluate the combined performance of the cytokines in identifying TB patients among HIV-infected individuals. Results: According to the clinical diagnosis information of the subjects, 35 cases with unknown diagnosis were excluded, and 97 cases were finally included in the analysis, including 44 cases of TB patients and 53 cases of non-TB patients. The ΔΔCt values (median (quartile)) of MTB-antigen specific IL-18 and IFNG in the TB group were 0.5601 (-0.0207, 1.2880) and 1.0130 (0.0284, 3.9950), respectively, which were significantly higher than those in the non-TB group (0.0364 (-0.6420, 0.7438) and 0.3727 (-0.5992, 1.2460), respectively), with statistically significant differences (Z values were -2.284 and -1.989, P values were 0.018 and 0.028). The ΔΔCt values (median (quartile)) of MCP-1, MCP-2, CXCL9, and CXCL10 in the TB group were -1.1660 (-1.8920, -0.5699), -1.4640 (-3.5530, 0.5763), -1.7680 (-6.3950, -0.2807), -1.8260 (-4.6000, -0.0814), respectively, which were significantly lower than those in the non-TB group (-0.5803 (-1.0040, 0.1794), -0.2367 (-1.3010, 0.7079), 0.2730 (-1.2750, 1.8360), -0.2505 (-0.6528, 0.9105)), with statistically significant differences (Z values were 3.162, 2.529, 3.745, 3.743, respectively; P values were 0.003, 0.014, 0.001, and <0.001). ROC analysis showed that the area under the curve for IL-18, MCP-1, MCP-2, CXCL9, CXCL10, and IFNG ranged from 0.632 to 0.724. Based on Lasso analysis, the area under the curve for the combined detection of IL18, MCP-2, and CXCL10 was 0.797, which was higher than any single indicator. Conclusion: The combination of IL18, MCP-2, and CXCL10 can assist in identifying TB cases among HIV-infected individuals.

Key words: Mycobacterium tuberculosis, HIV, Infection, Cytokines, Diagnosis, differential