Role of Peripheral Blood T Helper 17 Cells in Non-Small Cell Lung Cancer of Different Clinical Stages, Pathological Types and Differentiation Degrees

<bold>Background: </bold>We aimed to explore the roles of T helper 17 (Th17) cells and cytokines interleukin 17 (IL-17), IL-6, IL-4, transforming growth factor beta (TGF-beta) and gamma-interferon (IFN-gamma) in the peripheral blood of patients with non-small cell lung cancer (NSCLC) of different clinical stages, pathological types, and differentiation degrees.<bold>Methods: </bold>A total of 120 NSCLC patients admitted and 80 healthy people receiving physical examinations from June 2019 to October 2021 were enrolled as the case group (TNM stage: I, II, III and IV; pathological type: adenocarcinoma and squamous cell carcinoma; differentiation degree: low and moderate-high) and the control group, respectively. The serum levels of IL-17, IL-6, IL-4, TGF-beta and IFN-gamma were measured using an enzyme-linked immunosorbent assay. Th17 cells were counted by flow cytometry.<bold>Results: </bold>The case group had higher levels of Th17 cells, IL-17, IL-6, IL-4, and TGF-beta and lower IFN-gamma level in the peripheral blood than those of the control group (p < 0.05). NSCLC patients with different TNM stages had significantly different levels of Th17 cell, IL-17, IL-6, TGF-beta, and IFN-gamma (p < 0.05). The expression levels of Th17 and IL-6 in patients with lowly differentiated NSCLC were lower than those of patients with moderately and highly differentiated NSCLC, while the IFN-gamma expression level followed an opposite trend (p < 0.05). The count of Th17 cells in the peripheral blood of NSCLC patients had significantly positive correlations with IL-17, IL-6, IL-4, and TGF-beta levels, but negative correlation with IFN-gamma level (p < 0.05).<bold>Conclusions: </bold>The count of Th17 cells increases significantly in NSCLC patients and has correlations with TNM stage and differentiation degree.