Cell found that worsens rheumatism


Japanese scientists have discovered a new immune cell that exacerbates rheumatoid arthritis, according to an article the team recently published in the online edition of U.S. journal Nature Medicine.

Rheumatoid arthritis, an inflammatory disorder that mainly affects joints, occurs when excessive immune response destroys bone.

The new cell is created when the cell that originally controlled the excessive immune reactions mutates. Afterward, it powerfully promotes the activities of osteoclast, a cell that destroys bones, they said, announcing the results of experiments on mice.

The same mutation is believed to happen in human arthritis patients, said the team, which includes University of Tokyo visiting researcher Noriko Komatsu and professor Hiroshi Takayanagi.

Bones and cartilage in joints are usually shielded by synovial membrane and fluid secreted from it. In arthritis patients, abnormal growth of cells in the membrane causes inflammation. The team also found that interleukin-6 released by such cells triggers the mutation.