Objective: Characteristic cellular changes have previously been reported in the bone marrow of patients with rheumatoid arthritis (RA). We investigated the levels of various cytokines in RA bone marrow.
Methods: We studied 25 patients with RA (22 women and 3 men) and 10 trauma patients (7 women and 3 men) as non-RA controls. Twelve kinds of cytokines [interleukin (IL)-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-6, IL-7, IL-8, granulocyte colony stimulating factor, granulocyte/macrophage colony stimulating factor, tumor necrosis factor (TNF)-alpha, and TNF-beta] were assayed by ELISA in iliac bone marrow serum (BMS), tibial BMS, and peripheral blood serum.
Results: Markedly elevated levels of IL-6 and IL-8 were detected in iliac BMS, and much lower levels were found in tibial bone marrow and peripheral blood serum. The levels of IL-6 and IL-8 in iliac BMS showed a close relationship to the extent of synovial proliferation.
Conclusion: Iliac bone marrow may be an important site for the production or accumulation of IL-6 and IL-8 in RA, and these cytokines may influence synovial proliferation in patients with polyarthritis.