The influence of blood group differences in allogeneic hematopoietic peripheral blood progenitor cell transplantation

RhD mismatch does not affect haematopoietic recovery, graft-versus-host disease and survival in allogeneic haematopoietic cell transplantation: A Japanese registry-based study

BACKGROUND AND OBJECTIVES

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.

MATERIALS AND 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.

CONCLUSION

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.

Clinical Impact of Recipient-Derived Isoagglutinin Levels in ABO-Incompatible Hematopoietic Stem Cell Transplantation

ABO incompatibility is not considered a contraindication for hematopoietic stem cell transplantation (HSCT). We hypothesized that recipient-derived isoagglutinin (RDI) levels could play a critical role in clinical outcomes. In this study, we compared clinical outcomes such as survival, GVHD, infection, relapse, transfusion, and engraftment, among ABO-compatible patients (ABOc), ABO-incompatible patients (ABOi) with low RDI, and ABOi patients with high RDI. The ABOi with high RDI group was defined as recipients with more than 1:16 RDI levels. We analyzed 103 recipients (ABOc, 53; ABOi with low RDI, 36; ABOi with high RDI, 14). The ABOi with high RDI group showed a decreased 1-year survival and increased acute GVHD grade IV and RBC transfusion (p = 0.017, 0.027, and 0.032, respectively). The ABOi with high RDI group was an independent risk factor for increased death, RBC transfusion, and poor platelet (PLT) engraftment (odds ratio (OR) = 3.20, p = 0.01; OR = 8.28, p = 0.02; OR = 0.18, p = 0.03, respectively). The ABOi with high RDI group showed significantly delayed PLT engraftment. In conclusion, this is the first study underscoring high RDI levels as a marker predicting unfavorable outcomes in ABOi HSCT.

Selective ABO immunoadsorption in hematopoietic stem cell transplantation with major ABO incompatibility

OBJECTIVE

ABO mismatch between donor and recipient occurs in 40% of allogeneic hematopoietic stem cell transplantations (HCT). Different strategies have been described to reduce isohemagglutinins (IHA) before HCT. We describe the effect of selective ABO immunoadsorption (ABO IA) on erythrocyte transfusion rate and the development of post-transplant pure red cell aplasia (ptPRCA).

METHODS

63 patients with major ABO incompatibility were retrospectively analyzed. Nine patients with major ABO incompatibility and high-IHA titer were treated by ABO IA before HCT. We analyzed the need for transfusion and the occurrence of ptPRCA. We compared the outcome with patients treated by other methods to reduce IHA.

RESULTS

In all nine patients treated by ABO IA, IHA decreased in a median four times. PtPRCA occurred in one patient. The median number of transfusions was 8 (range: 0-36) between d0 and d100. In 25 patients with high-IHA titer without treatment or treated by other methods to reduce IHA, the need for transfusions was comparable. No difference in the incidence of ptPRCA was observed.

CONCLUSIONS

Selective ABO IA is a feasible, safe, and effective method to reduce IHA before HCT in major ABO incompatibility. No effect on transfusion rate or ptPRCA compared to other strategies could be observed.

Temporal Change in Blood Group after Bone Marrow Transplant: A Case of Successful ABO-Incompatible Deceased Donor Transplant

ABO-incompatible kidney transplantation has been successfully utilised in a deceased donor and living donor kidney transplantation to improve organ utilisation and decrease waiting times. We describe a case of a successful, unanticipated ABO-incompatible donation after cardiac death (DCD) kidney transplant in a patient who had a previous ABOi haematopoietic stem cell transplant (HSCT) and had reverted to his original blood group B, after matching as a blood group A recipient with a blood group A donor. The recipient was unsensitized with a cPRA which was 0% and no donor-specific antibodies and zero HLA mismatch. An urgent anti-A titre was 1 : 2. Given the low antibody titres, we proceeded to transplantation. The patient developed delayed graft function and required dialysis on postoperative day 1 and day 2. The creatinine fell spontaneously on day 5, with progressively increased urine output and stable graft function on discharge at day 6. Anti-A titres were 1 : 1 on serial postoperative measurements. There were no rejection episodes, and the patient has a functioning graft at 16 months posttransplant. We describe a rare case in which the blood group can change after stem cell transplant and should be checked. We also demonstrate that a DCD ABOi transplant in the context of low anti-A titres for a patient with previous ABOi stem cell transplant can be performed successfully with standard immunosuppression.

[Relevance of antibodies in hematopoietic stem cell transplantation: Antibodies anti-HLA, anti-platelets, anti-granulocytes, anti-erythrocytes and anti-MICA. Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The presence of allo-antibodies in the serum of a recipient awaiting hematopoietic stem cell transplantation (HSCT) may have an impact on transfusion efficiency and/or donor choice, especially in the absence of an identical sibling donor. Prior to transplantation, donor specific anti-HLA (Human Leukocyte Antigen) antibodies (DSA) have a recognized effect on transplant outcome, correlated with the increasing MFI value and with the ability of such antibody to fix the complement fraction. Anti-platelet antibodies (anti-HLA class I and anti-HPA [Human Platelet Antigen]) are better involved in transfusion inefficiency and can be responsible for refractory status. ABO incompatibilities require a specific treatment of the graft in presence of high titer to avoid hemolytic adverse effects. Investigations of these antibodies should be carried out on a regular basis in order to establish appropriate transfusion recommendation, select an alternative donor when possible or adapt the source of cells. After transplantation, in case of delayed recovery or graft rejection, long term aplasia, persistent mixed chimerism or late release, and after elimination of the main clinical causes, a biological assessment targeted on the different type of antibodies will have to be performed in order to orient towards the cause or the appropriate therapy. Further studies should be carried out to determine the impact of anti-MICA antibodies and recipient specific anti-HLA antibodies, on the outcome of the transplantation.

Changes in Mean Corpuscular Volume and RBC Distribution Width Predict Erythrocyte Engraftment Following ABO-Incompatible Hematopoietic Stem Cell Transplantation

OBJECTIVES

The purpose of this study was to identify laboratory parameters representing erythrocyte engraftment to be used as an indicator to change the recipient to donor ABO group and Rh type following an ABO-incompatible hematopoietic stem cell transplant (HSCT). Studies have shown that ABO incompatibility does not have an effect on outcome of HSCT; however, the serologic consequences of these ABO-incompatible transplants can make it difficult to decide when to begin support with donor ABO/Rh-type blood products.

METHODS

This study explored the use of RBC distribution width (RDW), mean corpuscular volume, and hemoglobin as regularly tested laboratory parameters that could be used as surrogate markers for RBC engraftment in 65 patients who received ABO/Rh-incompatible HSCT.

RESULTS

The appearance of engrafted donor RBCs correlated with a peak in RDW (P = .002). In addition, our findings suggest that serologic changes in ABO/Rh appear to correspond with a peak in RDW (P = .002).

CONCLUSIONS

High values of RDW likely result from a substantial proportion of large, young erythrocytes from recent engraftment with smaller, older pretransplant erythrocytes from the recipient. Our findings suggest that peak RDW may be an indicator of erythrocyte engraftment, following an ABO/Rh-incompatible HSCT.

Transfusion support for matched sibling allogeneic hematopoietic stem cell transplantation (1993-2010): factors that predict intensity and time to transfusion independence

BACKGROUND

Patients undergoing allogeneic hematopoietic stem cell transplant require variable, often extensive transfusion support. Identification of factors that predict urgent, intensive, or special needs should improve management of these patients.

STUDY DESIGN AND METHODS

This is a retrospective study of red blood cell (RBC) and platelet transfusion support provided for sequential matched sibling donor allogeneic transplants conducted at the Clinical Center, National Institutes of Health, from 1993 through 2010. Factors potentially important for predicting quantity of RBC and platelet transfusions, and time to transfusion independence through Day 200 following hematopoietic stem cell transplantation were evaluated.

RESULTS

Subjects (n = 800) received 10,591 RBC and 10,199 platelet transfusions. Multivariable analysis demonstrated that the need for RBC pretransplant, CD34+ dose, transplant year, diagnostic category, and ABO match were significantly independently associated with quantity of RBC transfusions during Days 0 through 30. Only pretransplant need for RBCs, CD34+ dose, and transplant year had significance during Days 0 through 100. Similar analyses for quantity of platelet transfusions demonstrated that for both Days 0 through 30 and 0 through 100 significant factors were need for platelet support before transplant, CD34+ dose, transplant year, and transplant regimen. Of note, long term, during Days 101 through 200, only CD34+ dose remained significant for quantity of RBC and platelet transfusions. Analysis of time to transfusion independence demonstrated that patients with ABO major mismatches required longer to achieve freedom from RBC transfusion support compared to identical matches or those with minor mismatches.

CONCLUSION

Patient-specific factors including CD34+ dose and ABO match of the graft should be given particular consideration by transfusion services when planning support of patients receiving allogeneic hematopoietic stem cell transplant.

Efficacy of three consecutive therapeutic plasma exchanges in major ABO-incompatible hematopoietic stem cell transplantation

INTRODUCTION

We retrospectively analyzed data of recipients who underwent three consecutive therapeutic plasma exchanges (TPEs) before major ABO-incompatible (ABOi) hematopoietic stem cell transplantation (HSCT) in our hospital from 2012 to 2017 and evaluated the efficacy of TPE for successful ABOi HSCT.

MATERIALS AND METHODS

We investigated the efficacy of TPE in 29 recipients with major ABOi HSCT based on the following: (1) requirement of red blood cell (RBC) transfusion during 100 days, (2) erythrocyte engraftment by reticulocyte count at 3 months, and (3) erythropoiesis recovery by bone marrow examination at 1 month and 3 months after ABOi HSCT.

RESULTS

IgM and IgG donor-specific isoagglutinins (DSIs) of 31 cases of TPE were significantly decreased after three consecutive TPEs (IgM median, 1:32 to 1:2, P < .0001; IgG median, 1:256 to 1:8, P < .0001). We divided a total of 31 TPEs into two groups depending on their final DSI titers after TPE (group F, DSI > 1:16; group S, DSI ≤ 1:16). RBC transfusions were required more by group F (median, 12 units) than those by group S (median, 2 units, P = .001). Relative frequencies of erythrocyte engraftment and normal erythropoiesis after ABOi HSCT showed higher tendencies in group S than those in group F.

DISCUSSION

Our study demonstrated that three consecutive TPEs were effective in reducing DSI titer in major ABOi HSCT. Reduction of pretransplant DSI in recipients could decrease requirement for RBC transfusion. Three consecutive TPEs are necessary for successful erythrocyte engraftment and normal erythropoiesis in this setting.

Daratumumab for Delayed Red-Cell Engraftment after Allogeneic Transplantation

Daratumumab, a human IgG1κ monoclonal antibody targeting CD38, is used to treat multiple myeloma. We describe successful treatment with daratumumab in a case of treatment-refractory pure red-cell aplasia after ABO-mismatched allogeneic stem-cell transplantation. The patient was a 72-year-old man with the myelodysplastic syndrome who received a transplant from an HLA-matched, unrelated donor with a major ABO incompatibility (blood group A in the donor and blood group O in the recipient). The patient had persistent circulating anti-A antibodies and no red-cell recovery 200 days after transplantation. Standard treatments had no effect. Within 1 week after the initiation of treatment with daratumumab, he no longer required transfusions.

Donor-to-Recipient ABO Mismatch Does Not Impact Outcomes of Allogeneic Hematopoietic Cell Transplantation Regardless of Graft Source

The impact of ABO mismatch has been studied on various hematopoietic cell transplant (HCT) outcomes, including neutrophil and platelet engraftment, pure red cell aplasia, acute and chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), and overall survival (OS). Yet conflicting results have been reported. However, the impact of ABO mismatch on transplant outcomes with various graft types has not been carefully investigated. We analyzed the impact of various graft sources and type of ABO mismatch on transplant outcomes for 1502 patients who underwent HCT at the University of Minnesota between 2000 and 2014: 312 receiving marrow (BM), 475 filgrastim-mobilized blood (peripheral blood stem cell [PBSC]), and 715 umbilical cord blood (UCB) grafts. Neutrophil engraftment by day 28 was marginally less frequent in the bidirectional ABO mismatched transplants receiving UCB, whereas ABO matching had no influence on engraftment in the BM or PBSC cohorts. ABO mismatch led to no significant differences in platelet engraftment irrespective of stem cell source. We observed a modest but not significantly lower incidence of grades II/IV acute GVHD in the bidirectional ABO mismatched transplants in the UCB and the PBSC cohorts but not in the BM group. We found a higher incidence of chronic GVHD in the PBSC group, but it was not significantly lower in the minor ABO mismatched transplants. The incidence of chronic GVHD was similar in the major ABO mismatched transplants receiving BM. We found no significant difference in the OS and NRM between ABO matched and ABO mismatched transplants within each of the 3 graft source groups. Multivariable analysis adjusting for other relevant factors confirmed that ABO match status did not significantly influence the outcomes of either engraftment, acute or chronic GVHD or NRM. We conclude that ABO mismatch does not influence the outcomes of allogeneic HCT, regardless of stem cell source.

ABO blood group antigen mismatch has an impact on outcome after allogeneic peripheral blood stem cell transplantation

ABO blood group antigen incompatibility (ABO mismatch) is not an obstacle to allogeneic stem cell transplantation (allo-SCT). However, the impact on clinical outcome after allo-SCT remains controversial. We analyzed 512 patients after allogeneic peripheral blood SCT (allo-PBSCT) for an association of ABO mismatch with transfusion requirements, myeloid and platelet engraftment, the incidence of GvHD, relapse, transplant-related mortality (TRM), and overall survival (OS). A total of 260 patients underwent ABO-mismatched transplantation and the control group consisted of 252 patients with ABO-matched allo-PBSCT. We found a significant association between major-0 ABO mismatch (group 0 recipient/group A, B, or AB donor) and increased red blood cell (RBC) and platelet transfusion requirements (both P<.001) as well as delayed platelet engraftment (P<.001). Minor-A (group A recipient/group 0 donor) and minor-AB (group AB recipient/group 0, A, or B donor) ABO mismatch was significantly associated with an increased TRM after allo-PBSCT (P=.001 and P=.02). In multivariate analysis performed using Cox regression, minor ABO mismatch appeared as independent risk factor for TRM after allo-PBSCT. No association was found for ABO mismatch with the incidence of GvHD, relapse, and OS. Our results suggest that ABO blood group mismatch has a significant impact on the outcome and that minor-A and minor-AB ABO mismatch represents a risk factor for increased TRM after allo-PBSCT.

Complex Transfusion Issues in Pediatric Hematopoietic Stem Cell Transplantation

Advances in the fields of pediatric transfusion medicine and hematopoietic stem cell transplant have resulted in improved outcomes but also present new questions for research. The diagnostic capabilities involved in transfusion medicine have improved in recent times, now including methods for determination of red blood cell minor antigens, detection of anti-human leukocyte antigen antibodies, and noninvasive iron quantification. At the same time, transplants are being performed for more indications including nonmalignant disease and with less intense conditioning regimens that allow some recipient blood cells to persist after transplant. We are therefore faced with new opportunities to understand the implications of transfusion medicine testing and to develop data-driven guidelines relevant to the current-day approach to transfusion and transplantation.

Outcome of allogeneic stem cell transplantation for AML and myelodysplastic syndrome in elderly patients (⩾60 years)

Allogeneic stem cell transplantation (SCT) remains the best curative option for patients with refractory AML or with high-risk myelodysplastic syndrome (MDS). For decades, age alone had been widely used as the primary criterion to assess eligibility for allogeneic SCT; however, prospective studies to evaluate allogeneic SCT in elderly patients are still limited. A total of 187 patients (median age of 64 years, range 60-77 years) with AML (87%) or MDS (13%) transplanted between 1999 and 2014 were included in this retrospective analysis. Relapse-free survival (RFS) and overall survival (OS) at 3 years were 32% (95% confidence interval (CI): 25-39%) and 35% (95%CI: 27-42%), respectively. Overall survival was 49% (95%CI: 35-64%) in AML patients who were transplanted in first complete remission (CR1), but even patients with active disease did benefit from transplantation, showing an OS at 3 years of 30% (95%CI: 20-40%). Multivariate analysis revealed disease- and patient-specific risk indices as independent prognostic factors for OS and non-relapse mortality (NRM). In conclusion, our monocenter results indicate that patients should not be generally withheld from allogeneic SCT because of age or disease status only. Specific risk models incorporating disease status and disease-specific risk factors at the time of transplantation as well as existing comorbidities are helpful tools to assess transplantation-associated risk factors of elderly patients.

ABO-Mismatched Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative option for a variety of malignant and non-malignant hematological and congenital diseases. Due to the fact that the human leukocyte antigen system is inherited independently of the blood group system, approximately 40-50% of all HSCTs are performed across the ABO blood group barrier. The expected immune-hematological consequences after transplantation of an ABO-mismatched stem cell graft are immediate and delayed hemolytic complications due to presence of isohemagglutinins or passenger lymphocyte syndrome. The risks of these complications can partially be prevented by graft manipulation and appropriate transfusion support. Dependent on the kind of ABO mismatch, different effects on engraftment have been observed, e.g. delayed red blood cell recovery and pure red cell aplasia. Data on incidence of acute graft-versus-host disease (GVHD), non-relapse mortality, relapse, and overall survival are inconsistent as most studies include limited patient numbers, various graft sources, and different conditioning and GVHD prophylaxis regimens. This makes it difficult to detect a consistent effect of ABO-mismatched transplantation in the literature. However, knowledge of expectable complications and close monitoring of patients helps to detect problems early and to treat patients efficiently, thus reducing the number of fatal or life-threatening events caused by ABO-mismatched HSCT.

ABO blood group incompatibility as an adverse risk factor for outcomes in patients with myelodysplastic syndromes and acute myeloid leukemia undergoing HLA-matched peripheral blood hematopoietic cell transplantation after reduced-intensity conditioning

BACKGROUND

ABO incompatibility is not a contraindication to hematopoietic cell transplantation (HCT), but it has been associated with additional risks including delayed engraftment, pure red cell aplasia (PRCA), and higher transfusion needs. Data on these events and on patient survival after reduced-intensity conditioning (RIC) HCT are limited.

STUDY DESIGN AND METHODS

A total of 127 consecutive patients, 86 with acute myeloid leukemia and 41 with myelodysplastic syndromes, who underwent HLA-matched peripheral blood RIC allogenic HCT between 2005 and 2014 were retrospectively analyzed.

RESULTS

Eighty ABO-compatible, 26 major/bidirectional, and 21 minor-ABO-mismatch HCT were identified. Compared to the ABO-compatible group, major/bidirectional mismatches had increased red blood cell (RBC) transfusion requirement during the first 100 days (p = 0.009), delayed RBC and PLT engraftment (p = 0.0011 and p = 0.005, respectively), and higher incidence of grade II to IV acute graft-versus-host disease (aGVHD; p = 0.037). In multivariable analysis, major/bidirectional mismatches had significantly higher non-relapse mortality (NRM) and inferior disease-free survival (DFS) and overall survival (OS) compared with ABO-compatible patients (p = 0.01, p = 0.04, and p = 0.035, respectively). Minor ABO mismatch had no impact on survival (p = 0.99). Four (15%) of 26 major/bidirectional mismatches developed PRCA. There was a significant association between fludarabine plus busulfan conditioning and PRCA (p = 0.0046).

CONCLUSION

Major/bidirectional ABO mismatch is associated with higher NRM and shortened DFS and OS in the setting of RIC HCT. Increased transfusion need, delayed RBC and platelet engraftment, PRCA, and increased severity of aGVHD are additional complications contributing to the morbidity.

Is ABO mismatch another risk factor for allogeneic hematopoietic stem cell transplantation in pediatric thalassemic patients?

The ABO incompatibility between donor and recipient is not considered a barrier to successful allogeneic HSCT. Nevertheless, conflicting data still exist about the influence of ABO incompatibility on transplant outcome in pediatric patients with thalassemia. Fifty-one children with beta-thalassemia major who underwent allogeneic HSCT were enrolled this study. Twenty-three of them (45%) received an ABO-incompatible transplant [minor ABO mismatch: six (26%), major ABO mismatch: fourteen (61%), and bidirectional mismatch: three (13%)]. In this study, ABO incompatibility did not significantly impair GVHD, VOD, neutrophil and platelet engraftment, TRM, OS and TFS. Particularly in major and bidirectional ABO-mismatched patients, a delayed erythroid recovery was recorded as compared to the group receiving an ABO-compatible graft (median time, 31 and 38 days vs. 19.5 days; p: 0.02 and p: 0.03). Median time to red cell transfusion independence was significantly longer in major ABO-incompatible patients (median time, 87 days vs. 32 days; p: 0.001). Therefore, whenever feasible, major ABO-mismatched donors should be avoided in HSCT recipients, to prevent delayed erythroid recovery with prolonged RBC transfusion needs and impaired quality of life.

Impact of ABO blood group mismatch in alemtuzumab-based reduced-intensity conditioned haematopoietic SCT

The impact of ABO incompatibility on clinical outcomes following haematopoietic SCT (HSCT) remains controversial. This retrospective study assessed the effect of ABO mismatch on transplant outcomes and transfusion requirements in 594 patients undergoing reduced-intensity conditioned (RIC) HSCT with alemtuzumab in three UK transplant centres. We found no significant effects of minor, major or bidirectional ABO mismatch on overall survival, relapse-free survival, nonrelapse mortality or relapse incidence. Although the rate of acute GVHD was unaffected by ABO mismatch, the incidence of extensive chronic GVHD was higher in patients with minor and major mismatch compared with those who were ABO matched (hazard ratio (HR) 1.74, P=0.032 for minor, HR 1.69 P=0.0036 for major mismatch). Red cell and platelet transfusion requirements in the first 100 days post transplant did not differ by ABO mismatch. In this large UK series, ABO mismatch in RIC HSCT has no clinically significant effect on survival outcomes but appears to modify susceptibility to extensive chronic GVHD.

ABO mismatch is associated with increased nonrelapse mortality after allogeneic hematopoietic cell transplantation

We evaluated ABO associated outcomes in 1737 patients who underwent allogeneic hematopoietic cell transplantation (allo-HCT) at Stanford University between January 1986 and July 2011. Grafts were 61% ABO matched, 18% major mismatched (MM), 17% minor MM, and 4% bidirectional MM. Median follow-up was 6 years. In multivariate analysis, overall survival (OS) was inferior in minor MM hematopoietic cell transplantations (median 2.1 versus 6.3 years; hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.19 to 2.05; P = .001) in comparison with ABO-matched grafts. ABO minor MM was associated with an increase in early nonrelapse mortality (NRM) (18% versus 13%; HR, 1.48; 95% CI, 1.06 to 2.06; P = .02). In an independent Center for International Blood and Marrow Transplant Research (CIBMTR) analysis of 435 lymphoma patients receiving mobilized peripheral blood grafts, impairment of OS (HR, 1.55; 95% CI, 1.07 to 2.25; P = .021) and increased NRM (HR, 1.72; 95% CI, 1.11 to 2.68; P = .03) were observed in recipients of ABO minor-MM grafts. A second independent analysis of a CIBMTR data set including 5179 patients with acute myeloid leukemia and myelodysplastic syndrome identified a nonsignificant trend toward decreased OS in recipients of ABO minor-MM grafts and also found ABO major MM to be significantly associated with decreased OS (HR, 1.19; 95% CI, 1.08 to 1.31; P < .001) and increased NRM (HR, 1.23; 95% CI, 1.08 to 1.4; P = .002). ABO minor and major MM are risk factors for worse transplantation outcomes, although the associated hazards may not be uniform across different transplantation populations. Further study is warranted to determine which patient populations are at greatest risk, and whether this risk can be modified by anti-B cell therapy or other peri-transplantation treatments.

Analysis of risk factors of cord blood transplantation for children

BACKGROUND

As cord blood (CB) is being used frequently as a source for heamtopoetic stem cell transplantation defining risk factors for transplantation outcome is an important issue.

PROCEDURE

The data of all single unit CB transplantation preformed in Israel from 1992 to 2011 were collected. The risk factors for myeloid engraftment, event free survival (EFS) and overall survival (OS) were studied in 87 children.

RESULTS

There were 49 children with hematological malignancies and 38 with non-malignant diseases. Cumulative rate of neutrophil recovery was 78.3%, while median time to myeloid recovery was 26 days. The incidence of platelet engraftment at 150 days was 53%, and the median time to platelet recovery was 36 days. ABO blood group matching between CB unit and recipient was associated with superior myeloid engraftment. Acute graft versus host disease of grades II-IV occurred in 33% of the patients. Chronic graft versus host disease occurred in 16% of patients. Probabilities of EFS and OS at 1 year were 45% and 57%, respectively. Factors associated with inferior OS were Rh major mismatch versus matched Rh and transplantation from unrelated donor versus related donor.

CONCLUSIONS

These results indicate that matching of ABO blood groups is an important factor that affects engraftment, and also that Rh matching seem to have an impact on OS, which was not previously described in the setting of CB transplantation.

Allogeneic peripheral blood stem cell transplantation using reduced-intensity conditioning in an outpatient setting in ABO-incompatible patients: are survival and graft-versus-host disease different?

BACKGROUND

Graft-versus-host disease (GVHD) is a major cause of morbimortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Minor ABO incompatibility has been associated with an increased risk of GVHD. We analyzed the impact of ABO matching on patient outcome after peripheral blood, reduced-intensity allo-HSCT in an outpatient setting, and its relationship with GVHD.

STUDY DESIGN AND METHODS

Data of 121 patients were included. All patients received allo-HSCT from HLA-identical siblings as outpatients using a reduced-intensity conditioning regimen. Influence of ABO matching as a risk factor for the development of GVHD and survival was analyzed using logistic regression and Cox proportional hazards regression, respectively.

RESULTS

Median age was 36 years (range, 1-71 years); 88 patients were ABO identical: 13 presented major mismatch and 20 minor mismatch, with an ABO incompatibility rate of 27.3%. The median follow-up period was 54 months (range, 0.3-120 months). Minor ABO incompatibility patients presented the highest rate of acute GVHD (aGVHD; 25%), in comparison with ABO-identical (20.5%) and major ABO incompatibility patients (15.4%; p = 0.79). The highest incidence of chronic GVHD (cGVHD) occurred in the context of minor ABO incompatibility (35%), in contrast to ABO-identical (30.8%) and major ABO incompatibility (15.4%). Survival was higher for patients in the minor ABO mismatch group; however, there was no significant correlation between ABO matching status and survival (p = 0.45).

CONCLUSION

Using this type of peripheral blood stem cell transplantation, minor ABO-mismatched allo-HSCT was associated with a higher incidence of aGVHD and cGVHD and with increased survival, albeit with no significance.

Minor ABO-mismatches are risk factors for acute graft-versus-host disease in hematopoietic stem cell transplant patients

We investigated the impact of ABO and Rhesus (Rh) blood group matching on the outcome of hematopoietic stem cell transplantation (HSCT) of 154 patients matched at 10/10 HLA loci with unrelated donors. ABO and Rh, as potential risk factors, were modeled with the clinical outcome--acute and chronic graft-versus-host disease (aGVHD, cGVHD), relapse, treatment-related mortality (TRM), and overall survival (OS)--by simple, multiple, and competing risk analyses. We found that minor ABO-mismatches represent a significant risk factor for aGVHD (II-IV) with an estimated risk increase of almost 3-fold (hazard ratio [HR]=2.92, 95% confidence interval [CI]: 1.43-5.95, P=.003), and even 4-fold for aGVHD (III-IV) (HR=4.24, 95% CI: 1.70-10.56, P=.002), but not for other transplant endpoints. No significant association of the Rh matching status with any of the HSCT endpoints was seen. These results suggest that ABO minor mismatches may play a role in aGvHD pathophysiology, possibly by providing the setting for T cell activation and antibody mediated damage. To decrease the risk of aGVHD, ABO matching should be considered in HSCT.

Significance of donor-derived isoagglutinins in ABO-Incompatible hematopoietic stem cell transplantation

Changes in isoagglutinin titers may have implications in the occurrence of hematological complications such as pure red cell aplasia or immune-mediated hemolysis. Furthermore, isoagglutinin titers could reflect immunohematological reconstitution after transplantation. The objective of this study was to examine the relationship between donor-derived isoagglutinins (DDIs) and graft-versus-host disease (GVHD). In total, 114 patients who underwent ABO-incompatible allogeneic hematopoietic stem cell transplantation (HSCT) were analyzed. Among these patients, 27.7% demonstrated increased donor-derived isoagglutinins (IDDIs) against red blood cells (RBCs) of the recipient, and 32.8% of the patients showed DDIs that were not against RBCs of the recipient. Patients with acute GVHD and DDIs against RBCs of the recipient tended to have higher incidences of IDDIs that occurred before posttransplant day 60 compared with patients without acute GVHD (17.3 vs. 3.9%, P=0.058). In patients with acute GVHD, IDDIs occurred significantly earlier (mean, day 32 vs. 181, P=0.046), the period of elevation was shorter (mean, day 36 vs. 134, P=0.033), and the donors were younger (mean, 28 vs. 36 years, P=0.01) than those without GVHD. Moreover, significant correlations were found between IDDIs and acute GVHD. Taken together, these data underscore a possible role for humoral immunity in GVHD after HSCT.

Impact of ABO mismatching on the outcomes of allogeneic related and unrelated blood and marrow stem cell transplantations for hematologic malignancies: IPD-based meta-analysis of cohort studies

BACKGROUND

The impact of donor-recipient ABO matching on outcomes after allogeneic stem cell transplantation has been a matter of controversy.

STUDY DESIGN AND METHODS

Individual patient data-based meta-analysis was conducted with a pooled data set provided through six published and one unpublished cohorts. Outcomes in recipients of peripheral blood or bone marrow transplantation for hematologic malignancies were evaluated. A multivariate Cox model was used to adjust differences in outcomes of patients receiving ABO-matched grafts with those receiving major, minor, or bidirectional mismatched grafts. Considering multiple testing, p values of less than 0.05 and 0.001 were considered significant for the primary and secondary endpoints, respectively.

RESULTS

In all, 1208 cases, including 697 ABO-matched and 202 major, 228 minor, and 81 bidirectional mismatched transplants, were analyzed. Overall, adverse impact of ABO matching on overall survival (OS), as a primary endpoint, was not observed (adjusted hazard ratios [95% confidence intervals]: major, 1.03 [0.82-1.30], p = 0.81; minor, 1.19 [0.97-1.47], p = 0.10; bidirectional, 1.25 [0.91-1.72], p = 0.17). Among related stem cell recipients, ABO matching had no significant influence on OS, while the minor and bidirectional mismatched groups among unrelated stem cell recipients exhibited lower OS with marginal significance, especially in patients with acute leukemia, patients who received transplants after 1998, and patients who underwent transplants at Asian centers.

CONCLUSIONS

Our meta-analysis demonstrates no adverse association between any ABO mismatching and survival. However, marginally lower OS found in recipients of minor or bidirectional mismatched grafts from unrelated donors suggested the need for larger studies focusing on unrelated transplants.

Immune hemolysis following ABO-mismatched stem cell or solid organ transplantation

PURPOSE OF REVIEW

Limitations in donor availability for stem cell or organ transplantation require that ABO-incompatible donors be used. Crossing ABO lines can have immune consequences characterized by immediate or delayed hemolysis.

RECENT FINDINGS

The use of peripheral blood as a stem cell source has essentially eliminated the risk for ABO-mediated hemolysis during infusion. Delayed red cell engraftment is expected after a major ABO-incompatible transplant and may be associated with pure red cell aplasia. The incidence of hemolysis associated with minor ABO incompatibility, the passenger lymphocyte syndrome, is waning because anti-B-cell immunosuppressive therapy is increasingly a component of graft versus host disease prophylaxis. The impact of ABO mismatching on stem cell recipient survival remains an area of active investigation. Although major ABO-incompatible organs are not used routinely for transplantation, minor ABO-incompatible organs are frequently used to meet the demand for organs. Passenger lymphocyte syndrome in this setting is a common complication, and has now been observed with every organ type and increasingly with non-ABO antibodies. Hemolysis can occur, but it is uncommonly severe.

SUMMARY

ABO-mismatched donors are commonly used for transplantation, and immune hemolysis remains the main complication. Clinicians must be vigilant in order to recognize hemolysis and implement appropriate therapy.

Lack of effect of donor-recipient Rh mismatch on outcomes after allogeneic hematopoietic stem cell transplantation

BACKGROUND

A recently published study has reported that donor-recipient Rhesus (Rh)-mismatched allogeneic hematopoietic stem cell transplantation independently led to significantly poorer survival. This suggests that donor-recipient Rh mismatching is a risk factor in allogeneic hematopoietic stem cell transplantation and should be a criterion for donor selection.

STUDY DESIGN AND METHODS

To further evaluate this issue, 258 consecutive patients who underwent myeloablative or submyeloablative allogeneic hematopoietic stem cell transplantation at our institution were analyzed to determine the association between the Rh mismatch pattern and 5-year actuarial survival. Secondary endpoints analyzed were the association of donor-recipient Rh mismatch and event-free survival, transplant-related mortality, incidence of acute graft-versus-host disease (GVHD), and incidence of chronic GVHD.

RESULTS

In our analysis, there were no significant associations between donor-recipient Rh mismatch pattern and overall survival, event-free survival, transplant-related mortality, incidence of acute GVHD, or incidence of chronic GVHD. On multivariate Cox proportional hazard analyses, the donor-recipient Rh mismatch pattern was not independently predictive of overall survival.

CONCLUSION

Donor-recipient Rh mismatch is not a risk factor in allogeneic hematopoietic stem cell transplantation and does not affect transplant outcomes.

Impact of ABO incompatibility on engraftment and transfusion requirement after unrelated cord blood transplantation: a single institute experience in Japan

The impact of ABO incompatibility between donor and recipient on engraftment and transfusion requirement was studied in 95 adults who underwent unrelated cord blood transplantation (CBT). The patients included 27 ABO-identical, 29 minor, 21 major and 18 bidirectional ABO-incompatible recipients. Neutrophil engraftment did not differ between ABO-identical/minor ABO-incompatible and major/bidirectional ABO-incompatible recipients (hazard ratio (HR) 1.17, P=0.48). Cumulative incidence of platelet engraftment in ABO-identical/minor ABO-incompatible recipients was higher than in major/bidirectional ABO-incompatible recipients (HR 1.88, P=0.013). In addition, fewer platelet transfusions were required during the first 60 days after CBT in ABO-identical/minor ABO-incompatible recipients (HR 0.80, P=0.040). RBC engraftment did not differ between the two groups (HR 1.25, P=0.33). However, fewer RBC transfusions were required in ABO-identical/minor ABO-incompatible recipients than in major/bidirectional ABO-incompatible recipients (HR 0.74, P<0.005). No patients developed pure red-cell aplasia after CBT. These results indicate that ABO incompatibility affected platelet engraftment and transfusion requirement of RBC and platelet in CBT recipients. Further studies including larger patient numbers are required to elucidate the impact of ABO incompatibility on the clinical outcome of CBT.

Lack of effect of donor–recipient ABO mismatching on outcome following allogeneic hematopoietic stem cell transplantation

Several recently published studies have suggested that patients who undergo ABO mismatched hematopoietic stem cell transplantation may be at increased risk for relapse, graft-versus-host disease, transplant-related mortality, and/or all-cause mortality. To investigate this issue further, we analyzed potential associations between the donor-recipient ABO mismatch pattern and the above outcome measures among 240 consecutive patients who underwent allogeneic hematopoietic stem cell transplantation at our institution. Our analyses uncovered no significant associations between donor-recipient ABO mismatch pattern and overall survival, event-free survival, transplant-related mortality, incidence of acute graft-versus-host disease (GVHD), or incidence of chronic GVHD. Our data do not support recent assertions that donor-recipient ABO mismatching is a major risk factor for patients undergoing allogeneic transplant, nor do they support recent assertions that ABO matching should be an important consideration in selecting allogeneic hematopoietic stem cell donors.

ABO-histo blood group incompatibility in hematopoietic stem cell and solid organ transplantation

In contrast to solid organ transplantation (SOT), ABO-histo blood group incompatibility is of minor importance for hematopoietic stem cell transplantation (HSCT). Patients receiving ABO-incompatible HSCT are at an increased risk for immune-mediated hematological complications including immediate and delayed hemolysis, late red blood cell engraftment and pure red cell aplasia, but seem not to have a worse overall survival or increased transplant-related mortality. This review gives an overview of the immunological mechanisms leading to complications associated with ABO-incompatible HSCT and describes approaches to prevent them. The current organ shortage in SOT stimulates the exploration of new strategies to expand the donor pool including ABO-incompatible SOT and xenotransplantation. Here, we discuss the hypothesis that ABO-incompatible transplantation may be viewed as a human in vivo model for the humoral immune mechanisms of antigen-mismatched transplantation. ABO-incompatible HSCT and SOT provide excellent possibilities to analyze graft accommodation and transplantation tolerance. Understanding the underlying mechanisms of graft survival in ABO-incompatible transplantation may facilitate new strategies to overcome the immunological barriers in SOT and xenotransplantation.