Morphometric analysis was carried out with a semiautomated process, as described in Supplemental Methods and Supplemental Figure 1. This process allows analysis of the whole section. Lymph nodes (found in five slides from control Ab− subjects, 1%), and regions with edge artifacts or nonspecific staining were manually excluded. For each slide, we quantified the total tissue area and separated it into exocrine and nonexocrine tissue (adipose and mesenchymal tissues, large ducts, and vessels) vs the insulin-stained area. The percentage of the total tissue area was converted into mass by multiplying it by the weight of the pancreas when available. When the weight of the pancreas was not available, only the ratio of the endocrine area to the total area was calculated. We used Photoshop CS4 (Adobe Systems) to perform thresholding on whole sections, and measurements were performed using ImageJ (http://rsbweb.nih.gov/ij/). Given that only the cytoplasm was stained for β-cells using the insulin Ab, we developed another Photoshop script to quantify the surface of the entire islet.