Abstract

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease primarily mediated by T helper 17 (T H 17) cells. We previously showed that Itch/WWP2 double knockout (DKO) T cells produce high levels of type 2 cytokines, driving spontaneous autoinflammation. Here, we report that DKO T H 2-high carrying autoantigen-specific TCR (2D2) develop atypical spontaneous experimental autoimmune encephalomyelitis (EAE), with CD4 + T cells simultaneously producing IL-4 and GM-CSF, directly causing neuroinflammation. Unexpectedly, IL-4 deletion in DKO T H 2-high 2D2 mice exacerbates T H 17-driven classical EAE, indicating a T H 2 to T H 17 conversion. Furthermore, we show that the JAK3/STAT5 signaling pathway is critical for maintaining T H 2 lineage stability by modulating Blimp1 and c-Maf thereby suppressing T H 17 differentiation. Importantly, we find that this phenomenon can also be observed in dupilumab-treated patients with atopic dermatitis who develop psoriasis. Thus, our findings uncover the molecular antagonism and plasticity in the T H 2 and T H 17 cell programs and identify potential therapeutic targets for modulating T H 2 and T H 17 cell responses in autoimmune diseases. The contribution of T helper 2 (Th2) cells to the pathogenesis of neuroinflammation is underexplored. Here, the authors show that MOG 35-55 -specific 2D2-TCR transgenic mice lacking Itch and WWP2 in CD4  +  T cells develop EAE symptoms primarily driven by Th2 trans-differentiation into pathogenic Th17 cells in the absence of IL-4. Furthermore, they identify a Jak3/STAT5/Blimp1/c-Maf axis required for the maintenance of Th2 stability by repressing Th17 genes.