Not surprisingly, the frequency of Foxp3+GARP+ Tregs were inversely correlated with the LAA (r = − 0.63, P < 0.001) whereas the frequency of Foxp3+GARP− cells correlated with LAA of COPD patients (r = − 0.72, P < 0.001) (Fig. 5C). Here, FOXP3 is linked to chronic obstructive pulmonary disease.