The Abelson non-receptor tyrosine kinases, c-Abl and Arg, are important regulators of cellular processes in cancer, inflammation, infection, and neuronal dynamics. Recent research on the role for these kinases in processes involving interactions with the cytoskeleton or signaling molecules, may lead to further insight into the pathogenesis of a variety of disorders, including chronic inflammatory diseases. In a mouse model for multiple sclerosis, we recently reported that Arg deficient mice develop T-cell mediated autoimmune neuro-inflammation with the same severity as littermate controls, but display a different B-cell phenotype upon immunization. Here we comment on these results and discuss the role for Arg in B-cell activation and homeostasis.