Finally, beyond the use of insulin as a key autoantigen to downregulate the autoimmune response to β-cells in prediabetes and in new-onset T1D, a key issue remains whether or not immediate insulin therapy should be started in noninsulin dependent diabetes patients who are tested positive for islet cell autoantibodies, in particular anti-GAD autoantibodies. Here, INS is linked to type 2 diabetes mellitus.