Research Article Israt S Alam, Federico Simonetta, Lukas Scheller, Aaron T Mayer, Surya Murty, Ophir Vermesh, Tomomi W Nobashi, Juliane K Lohmeyer, Toshihito Hirai, Jeanette Baker, Kenneth H Lau, Robert Negrin and Sanjiv S. Gambhir DOI: 10.1158/0008-5472.CAN-20-1149 Abstract Graft versus host disease (GvHD) is a major complication of allogeneic hematopoietic cell transplantation (HCT), mediated primarily by donor T cells that become activated and attack host tissues.