Th17 cell subsets are increased in granulomatosis with polyangiitis (GPA). (A) IL-17+IL-10+ CD4+ T cells were increased in quiescent, untreated GPA compared to quiescent, treated GPA and healthy controls (HC). No difference was detected between HC and patients with active GPA. (B) IFNγ producing Th17 cells were increased in quiescent, untreated GPA and active GPA compared to HC. Means are indicated by the horizontal line, and the error bars represent the SD. (C) Representative fluorescence-activated cell sorter (FACS) plots of a HC and a GPA patient. IL-10 and IFNγ producing Th17 cells are depicted in the upper right corner (blue). Plots are gated on CD3+CD8neg T cells, 30,000 events were acquired for each sample in this gate. *P < 0.05, **P < 0.008.