ACKR2 and Autoimmunity: Interestingly, enhanced Th17 responses were associated with an increase in the abundance of B cells producing GM-CSF, a cytokine known to enhance Th17 cell development and survival.28 Thus, in the models we have tested, Ackr2-deficient mice are not less susceptible to autoimmunity and do not show suppressed T-cell responses, but can develop enhanced Th17 responses and greater numbers of GM-CSF+ B cells after immunization with protein autoantigen.