CCR6 and rheumatoid arthritis: In this study, we demonstrated that (1) the rate of the expression of CD14+RANKhigh on monocytes in untreated RA patients was elevated compared with that of those receiving treatment; (2) the rate of the expression of CD14+RANKhigh on monocytes was decreased with disease improvement after treatment with DMARDs in RA patients; (3) total area of OC from PBMC of HV was correlated with MFI of RANK; (4) the high-level expression of RANK on CD14+ cells was correlated with that of CCR6 in HV.