For example, the absence of Bregs in an animal model ofMS results in the development of more severe and acute forms of EAE [4, 6].Recently, it has been shown that the amount of regulatory B cells increases inresponse to the secretion of the proinflammatory cytokines IL-1β and IL-6after induction of arthritis [49].Secretion of these cytokines in mice with arthritis is controlled by bacteriain the intestine. Here, IL1B is linked to arthritic joint disease.