GAD1 and type 1 diabetes mellitus: Unexpectedly, and contrary to what has been described for other T1D autoantigens22, T1D patient responses were not polarised towards increased IFN-γ secretion, and both HD and T1D patients showed responses of comparable magnitude and type (Fig. 1 a–c and Supplementary Fig. 2a, b), with 42% HD and 40% T1D patients not secreting IFN-γ or IL-10 after GAD stimulation (Fig. 1c).