Notably, B-cell depletion therapies restored the activation of the signaling pathway to normal levels and restored the frequency of GM-CSF-producing B cells and the subsequent development of IL-10-regulatory B cells, suggesting a new mechanism to explain the success of anti-CD20 therapies in MS.258 Together, these findings underscore the complex role of B cells in MS and strongly suggest that their pathogenic potential extends beyond antibody production, involving antigen presentation and local immune regulation within the CNS. The gene discussed is IL10; the disease is myeloid sarcoma.