[Bone marrow plays an important role in joint destruction in patients with rheumatoid arthritis].

In iliac bone marrow the absolute number of mononuclear cells (MNCs) was increased in RA patients compared with the non-RA controls. In CD8 positive cell and myeloid cell fractions, significant differences were recognized between RA patients and non-RA controls. The presence of abnormal myeloid lineage cells in epiphyseal bone marrow adjacent to joints affected with severe RA was shown. Stroma cell lines from RA bone marrow with nursing activity were established and shown to play a pivotal role in the pathogenesis in RA bone marrow. Histologic study also shows that subchondral region expressing tissue-damaging proteinases plays an important role in joint destruction in RA.