HLA Class I Mismatches Reduce Survival after HCT in the Ptcy Era: A Study By the EBMT Cellular Therapy and Immunobiology Working Party

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.2178-2178
• Main Authors: Arrieta-Bolanos, Esteban, Bonneville, Edouard F., Robin, Marie, Gedde-Dahl, Tobias, Salmenniemi, Urpu, Kröger, Nicolaus, Yakoub-Agha, Ibrahim, Crawley, Charles, Choi, Goda, Broers, Annoek E. C., Forcade, Edouard, Carre, Martin, Poiré, Xavier, Huynh, Anne, Reményi, Péter, Lenhoff, Stig, Ciceri, Fabio, Tholouli, Eleni, Schröder, Thomas, Deconinck, Eric, Carlson, Kristina Elisabet, de Wreede, Liesbeth C., Hoogenboom, Jorinde D., Malard, Florent, Ruggeri, Annalisa, Fleischhauer, Katharina
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-185945

Introduction: Human leukocyte antigen (HLA) compatibility between patient and donor is a mainstay in allogeneic hematopoietic cell transplantation (HCT) to reduce the risk of potentially fatal graft-versus-host disease (GvHD). Traditionally, mismatches at HLA class I (HLA-A, HLA-B, HLA-C) and class II (HLA-DRB1) have been associated with significantly reduced overall survival (OS) and increased risks of non-relapse mortality (NRM) and acute (a)GvHD compared to fully matched donors (Lee et al. Blood 2007). This has resulted in a preference for 8/8 (10/10 in Europe) HLA-matched donors in unrelated HCT (Dehn et al. Blood 2019). More recently, interest in expanding the donor pool to patients lacking a fully matched donor (Shaw et al. JCO 2021 &TCT 2023) and advances in the management and prevention of GvHD, in particular with post-transplant cyclophosphamide (PTCy) (Bolaños-Meade et al. NEJM 2023), are increasing the use of mismatched (i.e.