CD8+ T cells expressing IL-10 are associated with a favourable prognosis in lung cancer.

The dual role of tumour-infiltrating macrophages and lymphocytes on nonsmall cell lung cancer (NSCLC) progression and prognosis may be due to the differential activity of their phenotypes. To investigate the impact of inflammatory cells on NSCLC, we first quantified the number of macrophages (CD68+) and lymphocytes (CD8+ and CD4+) and the percentage of CD8+ cells expressing IL-10 (CD8+/IL-10+) in tumour stroma and epithelium. Then, we evaluated the possible relationships between the numbers of these cells and the clinicopathological features and the overall survival of patients. Paraffin-embedded sections of surgical specimens from 64 patients who had undergone surgery for NSCLC were immunostained with antibodies directed against CD68, CD4, CD8 and IL-10. The percentage of CD8+/IL-10+ cells was higher in cancer stroma of patients with stage I NSCLC than in those with stages II, III, and IV. High percentages of stromal CD8+/IL-10+ cells were associated with longer overall patient survival. In contrast, the number of CD68+, CD8+ and CD4+ cells did not differ between stage I NSCLC and stages II, III, and IV. In conclusion, the survival advantage of patients with stage I NSCLC may be related to the anti-tumour activity of the CD8+/IL-10+ cell phenotype.