OBJECTIVETo evaluate the distribution of CD4+ CD25+ regulatory T-cells (T-regs) in tumor-draining lymph nodes (TDLN) in patients with non-small cell lung caner (NSCLC), and to investigate the effect of CD4+ CD25+ T regulatory cells on the immune status of TDLN and the progression of NSCLC.

METHODSRegional tumor-draining lymph nodes of 53 NSCLC patients were resected during the operation. The percentage of CD4+ CD25+ T-regs as a subset of CD4+ T cells and CD8+ T cells were detected by immunofluorescence and regular immunohistochemistry, respectively. The level of cytokines TGF-beta1 and IL-10 was detected by real time quantitative RT-PCR.

RESULTSCD4+ CD25+ T-regs in tumor-infiltrating lymph nodes from the patients with NSCLC accounted for 28.80% +/- 8.06% of total CD4+ T cells, and were significantly increased comparing with that (15.48% +/- 4.66%) in the tumor-free lymph nodes (P < 0.01). The percentage of CD4+ CD25+ T-regs in TDLN of NSCLC patients was negatively correlated with the amount of CD8+ T cells within the lymph nodes (r = -0. 756, P < 0.001), but positively correlated with the level of TGF-beta1 (r = 0.645, P < 0.001) and IL-10 (r = 0.769, P < 0.001). It also increased as NSCLC getting progressed, which was 30.42% +/- 7.47% in stage III versus 16.22% +/- 4.88% in stage I and III; 32.58% +/- 7.52% in N2 versus 22.76% +/- 4.67% in N1, with a significant difference between the two groups, respectively (P < 0.01).

CONCLUSIONThe population of CD4+ CD25+ T regulatory cells in tumor-draining lymph nodes in patients with non-small cell lung caner is positively correlated with the progression and infiltration of lung cancer, which might provide new immunologic method to evaluate the progression and prognosis of non-small cell lung caner. The outcomes of biotherapy for NSCLC may be improved in the future through regulating the CD4+ CD25+ T regulatory cells.