Study of value of cytokine detection in urine and lavage fluid of tuberculosis patients in clinical application in a hospital in Gansu, 2023

Objective To investigate the levels of cytokines in urine and lavage fluid of the patients with tuberculosis (TB) and explore the role of cytokines in the diagnosis of TB.

Methods A case-control study was conducted in 153 suspected patients who were treated and screened for TB in Lanzhou Pulmonary Hospital, Gansu from January 2023 to July 2023. According to the inclusion and exclusion criteria, a total of 74 patients with etiologically confirmed TB were classified as the active TB group, 27 cases with positive interferon (IFN-γ) test results were classified as latent infection group. 52 pneumonia, bronchiectasis and tumor patients with negative IFN-γ test results were classified as negative control group. The epidemiological and clinical data, urine and lavage fluid samples of the cases were collected. The expression levels of 8 cytokines, including interferon (IFN-γ), tumor necrosis factor (TNF-α), interleukin 2(IL-2), interleukin 4(IL-4), interleukin 6(IL-6), interleukin 10(IL-10), interleukin 17(IL-17) and interleukin 22(IL-22), were detected by double antibody sandwich enzyme-linked immunosorbent assay. The data were statistically analyzed and P<0.05 was considered statistically significant.

Results Eight cytokines were detected in urine and lavage fluid of 153 subjects included in the study. In urine samples, the expression levels of IFN-γ, IL-2 and IL-10 in the active TB group were lower than those in the other two groups, the differences were significant (P<0.05). There were no significant differences in TNF-α, IL-4, IL-6, IL-17 and IL-22 expression levels among the three groups (P>0.05). In the lavage fluid samples, the expression levels of IFN-γ, IL-2 and IL-10 in the active TB group were lower than those in the other two groups, and the expression level of IL-6 in the active TB group was higher than those in the other two groups, the differences were significant (P<0.05), while the differences in expression levels of TNF-α, IL-4, IL-17 and IL-22 were not significant among the three groups (P>0.05).

Conclusion Decreased expression of IFN-γ, IL-2 and IL-10 in urine and lavage fluid and increased expression of IL-6 in lavage fluid might be used as reference in the diagnosis of active TB.