The overall goal of this project is to extend studies examining human beta cells and immune cells in type 1 diabetes (T1D) to a new 3D fluorescent microscopy format for 500um or greater sized samples. These studies will adapt new tissue imaging methods (CLARITY) developed by Dr. K. Deisseroth (Nat Methods 2013). The specific aims are: 1. Adapt tissue transparency methods for pancreas sample preparation and multiple immunofluorescence staining. 2. Create robust imaging and data collection methods to produce 3D islet topographical maps. 3. Examine islets in situ from donors with prediabetes and established diabetes for evidence of β‐cell regeneration and death. 4. Characterize immune cell subtypes infiltrating islets and their expression of cytokines and chemokines.