CD8A and chronic obstructive pulmonary disease: Flow cytometry analysis was used further to compare the proportion and function of T cells and revealed a greater proportion of CD8+CD103+TRM within CD3+T cells in NSCLC with COPD (n = 9) compared to NSCLC without COPD (n = 24) (11.9% vs. 4.6%, P = 0.040).