The proportion of NKT-like cells expressing surface CD158e1 was also significantly lower in healthy smokers (2.1%, 0.2–7.9; p<0.001) and current smokers with COPD (2.2%, 1.6–6.8; p<0.001) compared to healthy non-smokers (13.3%, 9.0–20.2) (Figure 4iiB). This evidence concerns the gene KIR3DL1 and chronic obstructive pulmonary disease.