However, no differences in the frequency of CD45.2+ Th17 (CD4+IL-17A+FoxP3–) cells were observed between the 2 groups of mice (Figure 4G and Supplemental Figure 8C), pointing to increased arthritis in recipients of cTregs being dependent on enhanced instability rather than reduced suppressive ability of cTregs. Here, IL17A is linked to arthritic joint disease.