KIR3DL1 and chronic obstructive pulmonary disease: A significantly lower proportion of CD8+ T-lymphocytes from healthy smokers (0.8%, 0.1–2.2; p<0.001) and current smokers with COPD (0.7%, 0.1–3.9; p<0.001) expressed CD158e1 on the cell surface compared to healthy non-smokers (9.9%, 4.8–16.6) (Figure 4iiA).