We obtained durable mixed hematopoietic chimerism in prediabetic NOD mice using anti–CD117 monoclonal antibody, T cell depleting antibodies, JAK1/2 inhibition, and low-dose total body irradiation prior to transplantation of MHC-mismatched B6 hematopoietic cells, preventing diabetes in 100% of chimeric NOD:B6 mice. The gene discussed is JAK1; the disease is diabetes mellitus.