To this end, we stained pancreas tissue sections of T1D (n = 7) and non-diabetic donors (n = 6) from the Network for Pancreatic Organ Donors with Diabetes (nPOD) and Exeter Archival Diabetes Biobank (EADB; Supplementary Table 2), using the previously validated HLA-A Ab ARC0588, HLA-B Ab HC10 (the other HLA-B Ab JOAN-1 was not functional by immunofluorescence) and the HLA-A/B/C/E Ab EMR8-512 (Fig. 7a–c). Here, HLA-B is linked to diabetes mellitus.