Outcomes of patients who underwent treatment for anti-HLA donor-specific antibodies before receiving a haploidentical hematopoietic cell transplant

Pediatric and adolescent and young adult (AYA) patients who receive many blood product transfusions, such as individuals with sickle cell disease (SCD), severe aplastic anemia (SAA) or indolent hematologic malignancies, are at high risk for developing donor-specific antibodies (DSA). DSAs with mean fluorescence intensity (MFI) greater than 5000 have been associated with significant graft failure, but lower MFI values between 2000 and 5000 may result in poor graft function after hematopoietic cell transplant (HCT). Desensitization strategies have been developed to reduce the DSA burden in HCT recipients before graft infusion, but the experience with these strategies in the pediatric and AYA populations is not well described in the literature. Here, we describe our experience with successful desensitization by using a combination of treatment strategies in five pediatric and AYA patients, including a novel use of daratumumab in a young adult patient who had refractory DSAs and had suffered serious side effects from conventional desensitization strategies. The presence of elevated DSAs in pediatric and AYA recipients of a human leukocyte antigen (HLA)-mismatched haploidentical HCT can be overcome by a multipronged treatment strategy.