Abstract

Interleukin-6 (IL-6) is a pleiotropic cytokine which shows multiple biological functions. Pathological significance of IL-6 has been elucidated in various diseases including multiple myeloma, Castleman's disease, and rheumatoid arthrtis. Thus the blockade of IL-6 signal transduction may be therapeutically effective for these diseases. For this purpose, humanized anti-IL-6 receptor antibody was prepared, and its therapeutic efficacy has been examined. Immediately after administration of humanized anti-IL-6 receptor antibody to the patients with multiple myeloma, fever and systemic edema disappeared followed by the stability of M-protein which had been rapidly increased before the treatment. Humaniged anti-IL-6 receptor antibody also improved not only the chronic inflammatory symptoms but also laboratory findings such as hemoglobin, C-reactive protein, erythrocyte sedimentation rate observed both in Castleman's disease and in rheumatoid arthritis. The data suggest that the blockade of IL-6 signal transduction can be a new therapeutic approach based on the pathological significance of IL-6 in these diseases.