In the present study, we also detected a significant increase in the frequency of CD137+ Tregs in the spleen and PLN of our F1 mice expressing the B10 allele of Tnfrsf9. These results indicate that a more functional CD137 molecule alone leads to the accumulation of CD137+ Tregs, independent of other genes within the Idd9.3 region or the differential state of diabetes progression in NOD and NOD.Idd9.3B10 mice. The gene discussed is TNFRSF9; the disease is diabetes mellitus.