REMARKABLE ELEVATION OF INTERLEUKIN-6 AND INTERLEUKIN-8 LEVELS IN THE BONE-MARROW SERUM OF PATIENTS WITH RHEUMATOID-ARTHRITIS

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.