We showed that the percentages of insulin-positive cells and proinsulin-positive cells were significantly reduced in islets from donors with recent-onset or long-duration type 1 diabetes (median percentage of proinsulin-positive cells in islets was 85.94% vs 38.25% vs 0.19% for non-diabetic donors vs donors with short-duration type 1 diabetes vs donors with long-duration type 1 diabetes, respectively; the respective median percentage of insulin-positive cells in islet was 85.34% vs 41.55% vs 0.41%) (Fig. 3d, e). Here, INS is linked to type 1 diabetes mellitus.