Alopecia areata (AA) is a common disease of the immune system, known as an "autoimmune" disease. In the disease, the immune system mistaken destroys the hair follicle, causing hair to fall out. Despite many people having this disease, research into its cause and into new, better ways to treat AA has lagged far behind other similar diseases of the immune system. Currently, there are no Federal Drug Administration approved drugs for AA. Abatacept (made by Bristol-Myers Squibb) is a safe intervention known to effectively treat rheumatoid arthritis,another "autoimmune" disease, by fighting inflammation. There are some genetic and chemical similarities between those with active rheumatoid arthritis and AA, suggesting that treatment with the same drug is likely to be effective.