CD4 and Arthritis: Stimulates Tregs proliferation (47) but also IL-17 production by CD4 T cells. Mice lacking IGF-1R specifically in T cells exhibited impaired disease progression in EAE model [49 DiToro]. Peripheral CD4 and CD8+ T cells populations increased in mice following IGF-1 infusion (50). IGF-1R signalling contributes to T cell dependent inflammation in arthritis (51).