Our transcriptomic phenotyping of pancreatic cell types provides novel insights into pancreas biology, as well as the initial pathogenic events in T1D. We employed single-cell transcriptomics (10x Genomics Platform) on 35,134 cells from pancreatic islets of organ donors representing three disease states: those with T1D, those with autoantibodies (AAbs) towards pancreatic islet proteins but without a medical history of T1D (referred to as ‘AAB+’ donors), and donors without relevant AAbs or a history of diabetes (referred to as ‘Control’ donors)