Natural killer cells determine the outcome of B cell–mediated autoimmunity

Natural killer (NK) cells can affect the outcome of adaptive immune responses. NK cells, but not NK1.1+ T cells, were found to participate in the development of myasthenia gravis (a T cell–dependent, B cell– and antibody-mediated autoimmune disease) in C57BL/6 mice. The requirement for NK cells was reflected by the lack of a type 1 helper T cell response and antibodies to the acetylcholine receptor in both NK1.1+ cell–depleted and NK cell–deficient IL-18−/− mice. These findings establish a previously unrecognized link between NK cells and autoreactive T and B cells.