TNFSF13B and Autoimmunity: The establishment of long-lived ASCs in the bone marrow could also have important implications for treatment of ITP and other B cell–dependent autoimmune disorders: first, this population could sustain autoantibody levels following splenectomy, which may be sufficient to affect clinical manifestations; and second, long-lived ASCs in the bone marrow have been observed to be resistant to immunosuppressive agents (36) and to B cell–targeted therapies, such as anti-CD20 or anti-BAFF antibodies (32, 39), which may partly explain therapeutic failures.