INS and type 1 diabetes mellitus: In five donors with type 1 diabetes (no. 6052, no. 6195, no. 6325, no. SC115 and no. 6371), TLOs were detected in association with insulin-negative pseudo-atrophic islets (Fig. 4a, ESM Fig. 4d) and in close association with pancreatic ducts containing insulin-positive cells (Fig. 4b–d).