Interleukin-2 calms runaway reactions
A multitasking immune protein once pursued as a treatment to rev up the body's defenses might work better at toning them down. The compound, called interleukin-2, can halt and even reverse aberrant immune reactions where standard treatment has failed, French and U.S. research teams report in the Dec. 1 New England Journal of Medicine.
Interleukin-2, or IL-2, is a signaling protein that has been approved for use against cancer and was also tried as an immune booster for fighting HIV, the AIDS virus. But despite some success against melanoma and kidney cancer, IL-2 has been a disappointment. It turns out that IL-2 does more than send immune fighters into battle. It also ratchets down these defenses by triggering production of T regulatory cells, or T-regs, which keep other immune troops in line. That quality could benefit patients with disorders in which the immune system attacks healthy tissues, such as lupus, multiple sclerosis or rheumatoid arthritis.