CD4 and chronic obstructive pulmonary disease: After gating for lymphocytes, single cells were gated: (A) shows gating of CD4 + CD25+ T cells from single cells and CD127-CD45RA- cells from CD4 + CD25+ cells; (B) furthermore, FoxP3+ cells were gated in control non-smoker (CNS) and control smoker (CS), (C) COPD smoker (COPD S) and COPD reformed smoker (COPD RS).