Fig 2: Graphical analysis of T-cell subset frequencies in pleural effusions. (A) The frequency of CD4+IL-9+ cells in TPE (n = 30), MPE (n = 30), EMP (n = 14), and PPE (n = 14). (B) The frequency of CD4+IL-17+ cells in TPE (n = 30), MPE (n = 30), EMP (n = 14), and PPE (n = 14). (C) The frequency of CD4+IL-22+ cells in TPE (n = 30), MPE (n = 30), EMP (n = 14), and PPE (n = 14). (D) The frequency of CD4+CD25+FOXP3+ cells (Treg cells) in TPE (n = 30), MPE (n = 30), EMP (n = 14), and PPE (n = 14). TPE, tuberculous pleural effusion; MPE, malignant pleural effusion; PPE, parapneumonic pleural effusion; EMP, empyema. All values are presented as the median and 5%–95% percentile and comparisons made between TPE, and the other groups were performed using the Mann–Whitney U test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ns, non significant.

Fig 3: Gating strategy for identification of T-cell subsets. Representative flow cytometric dot plots showing expression of (A) IL-9 on CD4+ T-cells in a sample from a patient with a tuberculous pleural effusion (TPE). (B) Representative flow cytometric dot plots showing the expression of IL-17 on CD4+ T cells in a single TPE sample. Data from (A, B) are from duplicate samples from the same donor. (C) Representative flow cytometric dot plots showing the expression of IL-22 on CD4+ T cells in a TPE sample. (D) Representative flow cytometric dot plots showing expression of CD25+FOXP3+ on CD4+ T cells in a TPE subject. TPE, tuberculous pleural effusion.