PTPRC and arthritic joint disease: The frequency of OCPs, identified as CD3-B220-NK1.1-CD11b-/loCD115+ cells in periarticular tissues (distal tibia PBM and cells released from TMT joints) and CD3-B220-NK1.1-CD11b+CD115+ cells in peripheral tissues (SPL and PBL) (Figure 1B), was increased among hematopoietic CD45+ cells in arthritis (Figure 1C).