Long-term prognostic significance of interleukin-17-producing T cells in patients with non-small cell lung cancer

Abstract

The presence of interleukin (IL)-17-producing T cells has recently been reported in non-small cell lung cancer (NSCLC) patients. However, the long-term prognostic significance of these populations in NSCLC patients remains unknown. In the present study, we collected peripheral blood from 82 NSCLC patients and 22 normal healthy donors (NC). Percentages of IL-17-producing CD4⁺ T (Th17), CD8⁺ T (Tc17) and γδT cells (γδT17) were measured to determine their association with clinical outcomes and overall survival (OS) in NSCLC. All NSCLC patients were followed up until July 2018. Median follow-up time was 13.5 months (range 1-87 months). The 3- and 5-year survival rate was 27% and 19.6%, respectively. We found that Th17 cells and γδT17 cells were significantly increased, whereas Tc17 cells were markedly decreased in patients with NSCLC compared with those in NC. In addition, Th17 cells were significantly positively associated with T helper type 1 cells (Th1), whereas γδT17 cells were significantly negatively associated with γδT ⁺ interferon (IFN)-γ⁺ cells. High percentages of peripheral Tc17 cells were significantly associated with favorable 5-year OS (P = .025), especially in patients with early TNM stage (P = .016). Furthermore, high percentages of peripheral Th17 cells were positively associated with favorable 5-year OS in patients with late TNM stage (P = .002). However, no significant association was observed between γδT17 cells and OS, regardless of the TNM stage. In conclusion, our findings suggest that enhanced Th17 and reduced Tc17 cells in the peripheral blood could be a significant predictor of a favorable prognosis for NSCLC patients.

Keywords: NSCLC; IL-17; Tc17 cell; Th17 cell; γδT17 cell.

Figure 1

Decreased CD8⁺T and T helper type 1 (Th1) cells, increased γδT cells, Tc1 cells and regulatory T cells (Treg) in the peripheral blood of patients with non‐small cell lung cancer (NSCLC). PBMC from NSCLC patients and normal controls (NC) were isolated and evaluated by flow cytometry. Percentages of CD4⁺T cells (A), CD8⁺T cells (B), γδT cells (C), as well as Th1 cells (CD4⁺ IFN‐γ⁺) (D), Tc1 cells (CD8⁺ IFN‐γ⁺) (E), γδT⁺ IFN‐γ⁺ cells (F), and Treg in NSCLC patients and NC are shown. (H‐K) Frequencies of Th1, Tc1, γδT⁺ IFN‐γ⁺ and Treg in NSCLC patients with tumors at different TNM stages (H‐K) are shown. Bars represent means ± SD. *P < .05; **P < .01; ***P < .001. IFN, interferon

Figure 2

Decreased Tc17 cells, and increased Th17 cells and γδT17 cells in the peripheral blood of patients with non‐small cell lung cancer (NSCLC). Populations of Th17 cells, Tc17 cells and γδT17 cells in the PBMC of patients with NSCLC and normal controls (NC) were evaluated by flow cytometry. Representative plots and the quantitative analysis of Th17 cells (A and B), Tc17 cells (D and E) and γδT17 cells (G and H) are shown. (C, F and I) Frequencies of Th17, Tc17, γδT17 cells in NSCLC patients with tumors at different TNM stages are shown. Bars represent means ± SD. *P < .05; **P < .01; ***P < .001. IL, interleukin; TCR, T‐cell receptor

Figure 3

Interferon (IFN)‐γ and interleukin (IL)‐17 double‐positive T cells in the peripheral blood of non‐small cell lung cancer (NSCLC) patients. Population of CD4⁺ IFN‐γ⁺ IL‐17⁺ cells (A and B), CD8⁺ IFN‐γ⁺ IL‐17⁺ cells (D and E) and γδT⁺ IFN‐γ⁺ IL‐17⁺ cells (G and H) in the PBMC of patients with NSCLC and normal controls (NC) were evaluated by flow cytometry. Representative plots were gated on CD4⁺T cells, CD8⁺T cells, and γδT cells. (C, F and I) Frequencies of indicated cells in NSCLC patients with tumors at different TNM stages are shown. Bars represent means ± SD. *P < .05; ***P < .001

Figure 4

Relationship between interleukin (IL)‐17‐producing cells and their interferon (IFN)‐γ‐producing partners in peripheral blood of patients with non‐small cell lung cancer (NSCLC). Correlations between the IL‐17‐producing CD4, CD8, γδT cells and IL17⁺ cells (A‐C), IFN‐γ‐producing T cells (D‐E), γδT⁺IFN‐γ⁺ cells (F) and regulatory T cells (Treg) (G‐I) in patients with NSCLC variables were determined by Pearson coefficient analysis. Solid line, linear growth trend; r, correlation coefficient. P‐values are shown

Figure 5

Kaplan‐Meier analyses of the prognostic significance of interleukin (IL)‐17‐producing cells in non‐small cell lung cancer (NSCLC) patients. Sixty‐six NSCLC patients were divided into two groups based on their levels of IL‐17‐producing cells using cutoff values calculated by receiver operating characteristic curves (Th17: 1.15%; Tc17: 0.3%; γδT17: 2.33%). Five‐year overall survival rates for NSCLC patients with a high and low level of (A) Th17, (B) Tc17, and (C) γδT17 cells are shown. (D‐I) Five‐year overall survival rates for NSCLC patients in stratified analyses by TNM stage. NSCLC patients with (D‐F) early‐stage (n = 17) or (G‐I) late‐stage (n = 49) cancer. Survival rates were determined using the Kaplan‐Meier method and log‐rank test. Vertical bars indicate censored cases