Autoantigen-specific memory CD4+ T cells are prevalent early in progression to Type 1 diabetes

► GAD65- and insulin-specific CD4+ T-cell responses during preclinical phase of T1D. ► Memory CD4+ T cells to GAD65 more common in T1D and autoantibody-positive children. ► A higher total CD4+ T-cell response to GAD65 was also seen in autoantibody-positive. ► Presence of antigen experienced T cells encouraging for future prediction of T1D.