CD200 and arthritic joint disease: We then used imaging mass cytometry (IMC) to detect CD2+MHC-II+CCR2+ myeloid precursors and CD200+ (DKK3+FAP+CD45−CD31−) fibroblasts in the synovial tissues of individuals with early PsA who had just developed arthritis and individuals with psoriasis without arthritis (Fig. 5c).