ONLINE COVER A Cloak for Pancreatic Pseudoislets. The cover shows wild-type (top and left) and engineered hypoimmune (bottom and right) pancreatic pseudoislets derived from primary human pancreatic islet cells. The top and right pseudoislets were stained for somatostatin (blue), insulin (green), and glucagon (red). The bottom and left pseudoislets were stained for major histocompatibility complex (MHC) class I (red), CD47 (yellow), and nuclei (blue). Allogeneic pancreatic islet transplantation has been used to improve glycemic control in patients with diabetes but can provoke inflammatory reactions as well as allo- and autoimmunity, necessitating lifelong use of immunosuppressants by recipients. Hu et al. engineered allogeneic primary human pancreatic cells to lack MHC class I and II molecules, thereby hiding the cells from the recipient immune system. The engineered pancreatic cells were aggregated into pseudoislets which were then transplanted into immunocompetent, allogeneic, diabetic humanized mice. The hypoimmune pseudoislets survived and ameliorated diabetes in the mice without the need for treatment with immunosuppressants.