Non-cryopreserved Kx negative packed red cell concentrates to support hematopoietic stem cell transplantation in McLeod contiguous gene deletion syndrome.

Transfusion management of Kx- individuals with McLeod phenotype (MLP) is highly challenging, particularly as cryopreservation affects red blood cell (RBC) concentrate quality. We developed a concept to provide non-cryopreserved Kx- RBCs over the complete period of hematopoietic stem cell transplantation (HSCT) for treatment of X-linked chronic granulomatous disease (X-CGD) with MLP. An infant with a large deletion affecting 12 protein-coding genes, including DMD, PRRG1, LANCL3, XK, CYBB, and DYNLT3, leading to CGD, Duchenne muscular dystrophy, and MLP, was scheduled for HSCT with the need of Kx- blood supply. No Kx- and RhD compatible donors were identified by rare donor programs, and autologous blood collection was not possible. In an interdisciplinary multicenter effort pre- and post-HSCT blood management, including procurement of non-cryopreserved allogeneic Kx- RBCs from an individual with MLP, was orchestrated, balancing donations, storage, pediatric RBC preparation, and irradiation with the clinical schedule. Our concept ensured compatible blood supply from 100 days prior HSCT to the peritransplant phase. The patient received 5 non-cryopreserved Kx- pediatric RBCs and was discharged with complete chimerism at day +68. The screen was repeatedly negative for antibodies to high frequency RBC antigens. After 2.8 years, the patient remained independent of transfusions and was without signs of graft-versus-host disease. Close coordination between institutions and disciplines and process optimization allow readily available provision of non-cryopreserved Kx- RBCs to support HSCT to a patient with unique contiguous gene deletion syndrome of X chromosome.