The percentage of CD8+ T cells was significantly increased and CD4+ T cells significantly decreased in the COPD group compared to the control group (57 ± 8 and 69 ± 7 for CD4 and 43 ± 9 and 31 ± 8 for CD8 for COPD patients and controls respectively, P = 0.032 and P = 0.037 respectively). Here, CD8A is linked to chronic obstructive pulmonary disease.