Autoimmune disease develops when the immune system defends the body against the attacking disease. A research team from the National Jewish Health has identified a trigger for autoimmune diseases like lupus, Crohn''s disease and multiple sclerosis. Previous studies have identified a subset of B cells which accumulate in autoimmune patients, autoimmune and elderly female mice. The cells were named as Age-associated B cells or ABCs. The research team also showed that transcription factor T-bet would play a crucial role in the presence of ABC.