OBJECTIVE: ABO blood group mismatch between the donor and the recipient can affect the success of the transplant as well as problems with the red blood cells during allogeneic haematopoietic cell transplantation (HCT). However, the impact of the Rhesus (Rh) D mismatch on transplant outcomes in allogeneic HCT has been poorly elucidated.
METHODS: We retrospectively evaluated the impact of the RhD mismatch on post-transplant outcomes in 64,923 patients who underwent allogeneic HCT between 2000 and 2021 using a Japanese registry database.
RESULTS: Out of the whole group, 64,293, 322, 270 and 38 HCTs were done when the recipient or donor was RhD-mismatched with (+/+), (-/+), (+/-) or (-/-) combinations. The difference in RhD between recipient/donor (-/+), (+/-) and (-/-) did not affect haematopoietic recovery, acute and chronic graft-versus-host disease (GVHD), overall survival (OS), non-relapse mortality (NRM) or relapse when RhD (+/+) was used as the reference group in multivariate analysis.
CONCLUSIONS: Our registry-based study demonstrated that RhD mismatch between recipient and donor did not significantly impact haematopoietic recovery, GVHD, OS, NRM or relapse after allogeneic HCT. These data suggest that RhD mismatches may not need to be avoided for recipient and donor combinations in allogeneic HCT.

OBJECTIVE: Noninvasive fetal rhesus D (RhD) blood group genotyping may prevent unnecessary use of anti-D immunoglobulin (RhIG) in non-alloimmunized RhD-negative pregnancies and can guide management of alloimmunized pregnancies. We conducted a systematic review of the economic literature to determine the cost-effectiveness of this intervention over usual care.
METHODS: Systematic literature searches of bibliographic databases (Ovid MEDLINE, Embase, and Cochrane) until February 26, 2019, and auto-alerts until October 30, 2020, and of grey literature sources were performed to retrieve all English-language studies.
METHODS: We included studies done in serologically confirmed non-alloimmunized or alloimmunized RhD-negative pregnancies, comparing costs and effectiveness of the intervention versus usual care.
METHODS: Two reviewers extracted data from the eligible studies and assessed their methodological quality (risk of bias) using the Quality of Health Economic Studies (QHES) and Drummond tools. We narratively synthesized findings. Our review included 8 economic studies that evaluated non-invasive fetal RhD genotyping followed by targeted RhIG prophylaxis in non-alloimmunized pregnancies. Five studies further considered a subsequent alloimmunized pregnancy. The cost-effectiveness of the intervention versus usual care (e.g., universal RhIG or prophylaxis conditional on results of paternal testing) for non-alloiummunized pregnancies was inconsistent. Two studies indicated greater benefits and lower costs for the intervention, and another 2 suggested a trade-off. In 4 studies, the intervention was less effective and costlier than alternatives. Three studies were determined to be of high quality by both tools. Two of these studies favoured the intervention, and one assessed benefits in quality-adjusted life-years. No study clearly examined the cost-effectiveness of repetitive use of fetal genotyping in multiple non-alloimmunized or alloimmunized pregnancies. The cost of genotyping was the most influential parameter.
CONCLUSIONS: The cost-effectiveness of noninvasive fetal RhD genotyping for non-alloimmunized pregnancies varies between studies. Potential savings from targeted management of alloimmunized pregnancies requires further research.