Bad Blood or Sick Patient?

More than 90% of allogeneic hematopoietic stem cell transplant (allo-HSCT) patients receive red blood cell (RBC) or platelet transfusions in the peritransplant period. We tested the hypothesis that transfusions are associated with development of severe acute graft-versus-host disease (grade III/IV aGvHD) or mortality in allo-HSCT in a retrospective study of 322 consecutive patients receiving allogeneic bone marrow or G-CSF-mobilized blood stem cell grafts for hematological malignancies. Counting RBC and platelet units between day −7 pre-transplant and +27 post-transplant, but excluding transfusions administered after a diagnosis of aGvHD, yielded medians of 5 RBC and 2 platelet units transfused. 63 patients (20%) developed a maximal grade of III–IV aGvHD with onset up to day 150 post-transplant (median aGvHD onset of 28 days). HLA mis-match (HR 2.4 (1.2, 4.7), p=0.01), and transfusion of > median number of RBC units (HR 2.1 (1.1, 3.7), p=0.02) were independently associated with greater risk of grade III–IV aGvHD in a multivariable analysis model. Disease risk strata (HR 1.7 (1.2, 2.4) for high risk vs. low risk, p=0.005) and transfusion of > median RBC units (HR 1.4 (1.0, 2.0), p=0.054) were independently associated with inferior overall survival. These data support our hypothesis that peritransplant RBC transfusions are associated with the risk of developing severe aGvHD and worse overall survival following allo-HSCT, and suggest that strategies to reduce routine RBC transfusion may favorably reduce GvHD incidence and severity.