Using surface markers (see Methods and Fig 6), a 0.65 ± 0.06% of the CD4 T cells were canonical Th17 (CD4+CCR6+CD161+) and 0.1 ± 0.05% were Th22 (CD4+CCR6+CCR10+) in our cohort of RA patients (Tables 5 and 6). Here, CCR6 is linked to rheumatoid arthritis.