Fig. 6

Impaired suppressive function and enhanced IL-17 production of Tregs from COPD patients. A Representative intracellular staining of Foxp3 vs. IL-17 in non-smoker (n = 6), smoker (n = 6), and COPD patients (n = 6) at a different quartile after 5 h of stimulation with PMA/ionomycin and GolgiStop. B The proportions of Foxp3⁺IL-17⁺ subsets among CD4⁺ T cells in all subjects. One-way Kruskal–Wallis test with post-hoc multiple comparisons using the Dunn’s method. **p < 0.01; ***p < 0.001; C CD25⁺GARP⁺ Tregs and CD25⁻GARP⁻ responder T cells (Tresp) were isolated by FACS. For suppression and proliferation assays, CFSE-labeled Tresp cells were co-cultured with Treg cells with plate-bound anti-CD3 and soluble anti-CD28 for 96 h, alone or in 1:4 ratios. Tresp cells were isolated from non-smoker and Tregs were isolated from non-smoker, smoker and COPD patients in different quartiles. D Suppressive function of Tregs decreased with the CT scan quantification quartile. The flow cytometry plot shows dilution of CFSE labeled responder cells. The percentage of dividing cells is shown. E Suppressive function assay revealed that CD25⁺GARP⁺ Treg cells from COPD patients have a reduced suppressive capacity and associated with the severity of emphysema. Data are from n = 8 independent experiments (at least n = 3 subjects in 2 technical replicates). One-way ANOVA with post hoc pairwise multiple comparisons using Tukey’s test **p < 0.01; ***p < 0.001