Standardizing Definitions of Hematopoietic Recovery, Graft Rejection, Graft Failure, Poor Graft Function, and Donor Chimerism in Allogeneic Hematopoietic Cell Transplantation: A Report on Behalf of the American Society for Transplantation and Cellular Therapy
Mohamed A. Kharfan‐Dabaja, Ambuj Kumar, Ernesto Ayala, Mahmoud Aljurf, Taiga Nishihori, Rebecca Marsh, Lauri M. Burroughs, Navneet S. Majhail, A. Samer Al‐Homsi, Zaid Al‐Kadhimi, Merav Bar, Alice Bertaina, Jaap Jan Boelens, Richard E. Champlin, Sonali Chaudhury, Zachariah DeFilipp, Bhagirathbhai Dholaria, Areej El‐Jawahri, Suzanne Fanning, Ellen Fraint, Usama Gergis, Sergio Giralt, Betty K. Hamilton, Shahrukh K. Hashmi, Biljana Horn, Yoshihiro Inamoto, David A. Jacobsohn, Tania Jain, Laura Johnston, Abraham S. Kanate, Ankit Kansagra, Adetola A. Kassim, Leslie S. Kean, Carrie L. Kitko, Jessica Knight‐Perry, Joanne Kurtzberg, Hien Liu, Margaret L. MacMillan, Zahra Mahmoudjafari, Marco Mielcarek, Mohamad Mohty, Arnon Nagler, Eneida R. Nemecek, Timothy S. Olson, Betül Oran, Miguel‐Angel Perales, Susan E. Prockop, Michael A. Pulsipher, Iskra Pusic, Marcie Riches, Cesar Rodriguez, Rizwan Romee, Gabriela Rondón, Ayman Saad, Nina Shah, Peter J. Shaw, Shalini Shenoy, Jorge Sierra, Julie‐An Talano, Michael R. Verneris, Paul Veys, John E. Wagner, Bipin N. Savani, Mehdi Hamadani, Paul A. Carpenter
Abstract
Allogeneic hematopoietic cell transplantation (allo-HCT) is potentially curative for certain hematologic malignancies and nonmalignant diseases. The field of allo-HCT has witnessed significant advances, including broadening indications for transplantation, availability of alternative donor sources, less toxic preparative regimens, new cell manipulation techniques, and novel GVHD prevention methods, all of which have expanded the applicability of the procedure. These advances have led to clinical practice conundrums when applying traditional definitions of hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism, because these may vary based on donor type, cell source, cell dose, primary disease, graft-versus-host disease (GVHD) prophylaxis, and conditioning intensity, among other variables. To address these contemporary challenges, we surveyed a panel of allo-HCT experts in an attempt to standardize these definitions. We analyzed survey responses from adult and pediatric transplantation physicians separately. Consensus was achieved for definitions of neutrophil and platelet recovery, graft rejection, graft failure, poor graft function, and donor chimerism, but not for delayed engraftment. Here we highlight the complexities associated with the management of mixed donor chimerism in malignant and nonmalignant hematologic diseases, which remains an area for future research. We recognize that there are multiple other specific, and at times complex, clinical scenarios for which clinical management must be individualized.