The goal of this proposal is to define the lineage mechanism of ß-cell persistence in type 1 diabetes (T1DM). A few ß-cells often persist in T1DM pancreata. But, the lineage mechanism of ß-cell persistence in T1DM remains poorly understood. Our overarching hypothesis is that ß-cell persistence in T1DM is due to ongoing ß-cell regeneration. Alternatively, ß-cell persistence in T1DM could be due regional differences in islet autoimmunity, or because ß-cells acquire a degranulated state that protects them from autoimmune mediated destruction. These hypotheses are readily testable with NPOD samples. However, by traditional techniques the analysis would require a huge number of slides and a many years to analyze. Our approach combines multi-labeling (5 antigens can be simultaneously detected) and high-throughput imaging technologies. This strategy will allow us to carry out this analysis using an absolute minimum of precious NPOD slides in a precise manner.