Distribution of CD4⁺ and CD8⁺ T cells in tumor islets and stroma from patients with non-small cell lung cancer in association with COPD and smoking

Background and objective: The immune system plays an important role in non-small cell lung cancer (NSCLC) and chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the infiltration patterns of CD4⁺ and CD8⁺ T cells in NSCLC and to analyze their relation to COPD, smoking status and other clinicopathologic variables.
Materials and methods: Lung tissue specimens from 50 patients who underwent surgery for NSCLC (stages I–III) and 10 control group subjects were analyzed immunohistochemically.
Results: NSCLC patients had a greater number of CD4⁺ and CD8⁺ T cells infiltrating the lung tissue than the control group (P = 0.001) with predominant infiltration in the tumor stroma. We found a significant association between the number of total and tumor stroma-infiltrating CD4⁺ and CD8⁺ T cells, and smoking status (P < 0.05). There were more CD8⁺ T cells in the tumor stroma and fewer in the tumor islets in NSCLC patients with COPD as compared to NSCLC patients without COPD (P < 0.05). However, there was no such association between CD4⁺ T cells and COPD status. A high level of CD8⁺ T cell infiltration in the tumor stroma was independently associated with the coexistence of COPD in multivariate analysis (P < 0.05).
Conclusions: According to our data, COPD but not smoking seems to be associated with higher infiltration of CD8+ T cells in the tumor stroma of patients with NSCLC. It allows us to hypothesize that NSCLC patients with coexisting COPD may have a more favorable outcome due to anticancer properties of stromal CD8⁺ T cells.