Frequencies and numbers of Th17 cells in aplastic patients (AA) correlate with disease activity. PBMCs from healthy controls (n = 10) and AA patients (AA) at diagnosis (n = 18), in CR (n = 12) or in PRs (n = 12) were stained with anti-CD3 and anti-CD8 antibodies followed by intracellular IL-17 antibody and examined by flow cytometry after stimulation for 6 hours with PMA and ionomycin. (A) Representative flow cytometric analysis of IL-17 expression in CD8⁻ T-cell subsets (Th17 cells) in healthy control (left panel) as well as in AA at diagnosis (left middle panel), in CR (right middle panel), or in PR (right panel). The mean value of each group is indicated. (B) Frequencies of Th17 cells in healthy controls (●) and in AA at diagnosis (▵), in CR (▴) and in PR (○). The mean value of each group is represented (solid line). (C) Absolute numbers of Th17 cells in healthy controls (●) and in AA at diagnosis (▵), in CR (▴) and in PR (○). The mean value of each group is represented (solid line). (D) Frequencies (left panel) and absolute numbers (right panel) of Th17 cells in patients who obtained a CR. Normal values are indicated by gray bars. (E) Frequencies (left panel) and absolute numbers (right panel) of Th17 cells in patients who were PRs. Normal values are indicated by gray bars.