Detection of myeloid precursors (granulocyte/macrophage colony forming units) in the bone marrow adjacent to rheumatoid arthritis joints

Various cytokines were recently found to be involved in the pathogenesis of rheumatoid arthritis (RA) and particularly, cytokines with hematopoietic activity have been detected in synovial tissues. We counted the number of myeloid precursors in terms of granulocyte/macrophage colony forming units (CFU-GM) and the number of stromal cell progenitors in terms of fibroblast colony forming units (CFU-F) in the tibial bone marrow adjacent to the joints affected by RA (n=21), osteoarthritis (OA) (n=10), and trauma (n=2) using the colony formation unit assay