OSTEOCLASTOGENESIS IN ILIAC BONE-MARROW OF PATIENTS WITH RHEUMATOID-ARTHRITIS

Objective. To investigate osteoclastogenesis in bone marrow cells from patients with various pathogenic backgrounds known to induce osteopor osis, to identify specific factors that may cause generalized osteopor osis in patients with rheumatoid arthritis (RA). Methods. Bone marrow blood was obtained from 59 women, 36 with RA and 23 without RA. Patien ts with RA were classified as severe (26) and mild RA (10: 5 patients with and 5 without corticosteroid therapy). The non-RA subjects were d ivided into 3 groups, premenopausal (7), menopausal (8), and elderly ( 8), As a marker of bone resorption, the pyridinoline crosslinked telop eptide domain of type I collagen (ICTP) concentration in the bone marr ow supernatant was measured by radioimmunoassay. The bone marrow cells were cultured 14 days in the presence or absence of autologous bone m arrow supernatant; then the number of tartrate resistant acid phosphat ase positive multinucleated cells (TRAP positive MNC) was counted as a n indicator of osteoclastogenesis. Results. ICTP concentration of the bone marrow supernatant and the number of TRAP positive MNC showed rem arkable enhancement in some patients with severe RA, but these feature s were not observed in the 3 control groups. Conclusion. Increased bon e resorption and enhanced osteoclastogenesis were specifically observe d in the iliac bone marrow of patients with RA, especially those with severe RA. These phenomena can be considered to accompany generalized osteoporosis in RA.