Fig. 2

CD4⁺ T cell subsets in peripheral blood under physiological and disease conditions. Three subsets of CD4⁺ T cells defined by the expression of interferon-γ and interleukin-17. a-b Representative flow cytometry of Th1 and Th17 cells were shown. c-d The proportions of subsets among CD4⁺ T cells in never-smokers and smokers with normal lung function, and patients with COPD. Data were presented as median (IQR). Horizontal lines indicate median values. A p value< 0.05 was considered statistically significant