[Transfusion management and immuno-hematological follow-up after allogeneic hematopoietic cell transplantation: Recommendations of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)].

The French High Authority of Health (HAS) and National Drug Safety (ANSM) agencies recommendations issued in 2014, the French General Direction of Health (DGS) instruction published in November 2021, the French National Blood Bank (EFS) guidelines and the data available in the literature globally define "good transfusion practices" but provide little information about the immuno-hematological and transfusion management of patients who have received an allogeneic hematopoietic stem transplantation (allo-HCT). The aim of this workshop was to harmonize these practices in situations for which there are currently no recommendations. In order to anticipate possible transfusion issues after allo-HCT, we recommend performing, before the transplantation, an extended red blood cell phenotyping of the donor and a detection of HLA alloimmunization in the recipient. We recommend to systematically perform for minor ABO mismatches: a direct antiglobulin test between D8 and D20, and for major ABO mismatches; a titration of anti-A/anti-B antibodies and an erythrocyte chimerism at D100. At one-year post-transplant, we recommend carrying out an erythrocyte chimerism to allow, if necessary, the update of transfusion counselling (RH phenotype, irradiation of packed red blood cells).