In conclusion, our studies not only indicate strong preclinical application of JAK1/2 inhibition in the protection of ICI-T1DM development but demonstrate a critical role for IL-21+IFNγ+CD4+ Tfh cells in driving the mechanism of autoimmune attack and pancreatic injury in ICI-T1DM. The gene discussed is JAK1; the disease is type 1 diabetes mellitus.