CD4 and chronic obstructive pulmonary disease: As peripheral CD4+CD25−Foxp3+ T cells expressed high levels of CD45RO in COPD patients (Figure 3A), CD4+CD25−CD45RO+CD127+ T cells and CD4+CD25−CD45RO+CD127− T cells were used as substitutes for CD4+CD25−CD127+Foxp3+ T cells and CD4+CD25−CD127− Foxp3+ T cells, respectively; 27.4 ± 2.8% of peripheral CD4+CD25−CD45RO+CD127− T cells, in comparison to 15.5 ± 2.5 % of peripheral CD4+CD25−CD45RO+CD127+ T cells, expressed Foxp3 (Figure S2).