Risks of alloimmunization and hemolysis of RhDmismatched hematopoietic stem cell transplants: A BEST collaborative study
Recommended Citation
Kogler VJ, Fontaine MJ, Ziman A, Azimi V, Brancamp RL, Cataife G, Covington M, Delaney M, Eichbaum QG, Jacquot C, Kutner J, Lu W, Saifee NH, Shan H, Thibodeaux SR, Wali JA, Yeh AC, Hitomi Yokoyama A, Yunce M, Pagano MB. Risks of alloimmunization and hemolysis of RhDmismatched hematopoietic stem cell transplants: A BEST collaborative study. Vox Sang 2025; 120:464-465.
Document Type
Conference Proceeding
Publication Date
5-21-2025
Publication Title
Vox Sang
Keywords
autoantibody, rhesus D antibody, allogeneic hematopoietic stem cell transplantation, alloimmunization, antibody specificity, blood group rhesus system, Brazil, complication, conference abstract, controlled study, diagnosis, female, hematopoietic stem cell, hemoglobinopathy, hemolysis, human, major clinical study, retrospective study, therapy
Abstract
Background: The clinical implications of RhD-mismatched hematopoietic stem cell transplants (HSCT) with the risk of alloimmunization and hemolysis have not been fully investigated. Aims: To determine alloimmunization rate and the presence of hemolysis in the immediate post RhD-mismatched HSCT period. Methods: This is an international, multicenter, retrospective study including HSCT performed between 2010 and 2021. Patients with hemoglobinopathies were excluded. The database included immunohematology and HSCT information. The presence of newly developed (Table present) anti-D was evaluated 100 days post-HSCT, and hemolysis was evaluated by laboratory parameters and a review of medical records by two physicians. Statistical analysis was performed using Microsoft Excel and STATA. Each center obtained institutional review board approval and data use agreements prior to data collection and data sharing, respectively. Results: Ten large academic centers, 9 from the United States and 1 from Brazil, provided data of 8271 transplants with complete RhD information and unambiguous RhD typing (±). Of these, 19.9% (n = 1649) were RhD mismatched, including recipient D +/donor D-(n = 799, 48.5%) and recipient D-/donor D+ (n = 850, 51.5%). Among D+ recipients with D-donors, 8 demonstrated anti- D within 100 days after transplant for an alloimmunization rate of 1%, and 7 of these recipients had additional antibodies. There was only one delayed (>24 h) hemolytic event (see Table 1 for additional patient and transplant characteristics, and antibody specificities). Among D-recipients with D+ donors, 2 demonstrated anti-D for an alloimmunization rate of 0.2%. One case had a combination of anti-D and warm autoantibody, with evidence of delayed hemolysis; the other case only had anti-D with no evidence of hemolysis. Summary/Conclusions: The anti-D alloimmunization rate after RhDmismatched allogeneic HSCT is low and among the few who did develop a new alloanti-D, hemolysis is infrequent. Presumably, the development of anti-D in D+ recipients with D-donors originated from the donor graft, upon exposure to the recipient D antigen. Notably, alloimmunization against other antigens from the Rh blood group system was also observed in the majority of cases, suggesting that RhD antigen mismatch is not the sole immunizing antigen.
Volume
120
First Page
464
Last Page
465
