IL21 and type 1 diabetes mellitus: In light of previous evidence of some clinical efficacy of anti-CD20 therapy in type 1 diabetes patients [32], it is possible that pre-selected patients stratified on the basis of increased levels of IL-21, Tfh cells or with multiple circulating autoantibodies and IFN-γ production [33] could benefit to a greater extent from clinical interventions, such as B cell depletion, IL-2 replacement or anti-IL-21 therapy.