CCR5 and chronic obstructive pulmonary disease: The chemokine receptor CCR5, preferentially expressed by Th1/Tc1 cells producing IFN-γ, was reported to be increased in mild/moderate disease in comparison with control smokers [28], suggesting that, at variance with asthma, a prevalent Th1/Tc1 immunosurveillance develops in mild/moderate COPD patients in stable conditions (Fig. 4).