CD8A and chronic obstructive pulmonary disease: There was a significant decrease in the number of CD4+ CD56+CD3+ cells in COPD subjects (15.7%) compared to smokers (27.4%; p < 0.001) and HNS (27.9%; p < 0.001) but no significant difference in the double negative (DN, CD3+CD4-CD8-CD56+) subset was detected.