ABO incompatible stem cell transplantation in children does not influence outcome

The Impact of ABO Incompatibility on the Outcomes of Hematopoietic Stem Cell Transplantation: A Single-Center Study From Pakistan

Background and objective Allogeneic hematopoietic stem cell transplantation (alloHSCT) provides curative treatment for several hematological illnesses. In this study, we evaluated the impact of ABO compatibility and incompatibility on outcomes and complications related to hematopoietic stem cell transplantation (HSCT) performed for various hematological disorders at our center. Methodology This was a retrospective, single-center, cohort study in which patients were categorized according to the ABO match and mismatch status. The mismatch group was further subcategorized into major, minor, and bidirectional groups. Results A total of 117 patients underwent alloHSCT, out of which 82 (70.1%) were male and 35 (30%) were female. The median age of the patients was 9.5 years (range: 46 years). The most common indications for stem cell transplant were beta-thalassemia major (BTM; n=58, 49%) and aplastic anemia (AA; n=42, 35.8%). However, the outcomes in match and mismatch groups showed significant results for positive direct Coombs test (DCT), indicating the occurrence of hemolysis. Despite the increased need for blood transfusions, ABO blood group incompatibility (ABOi) had no negative impact on the clinical results. Conclusion Based on our findings, ABO incompatibility does not affect the outcomes in patients undergoing alloHSCT. Patient monitoring can aid in early detection and treatment, thereby minimizing the frequency of fatal events.

A retrospective study to assess the impact of ABO incompatibility on outcomes of allogeneic peripheral blood stem cell transplants at a tertiary care hospital in Western Maharashtra

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) has emerged as a curative measure for life-threatening hematological disorders. It can be autologous or allogeneic depending on the disease characteristics. Providing transfusion support to the transplant patients can be challenging, especially in AB-mismatched allogeneic HSCT. In this study, we investigated the impact of ABO incompatibility in patients undergoing allogeneic HSCT.

MATERIALS AND METHODS

A retrospective review was conducted in 76 patients with hematological diseases who underwent allogeneic HSCT. Transfusion requirements, engraftment profile, incidence of graft versus host disease (GvHD), and mortality for a period of 1 year were analyzed.

RESULTS

ABO incompatibility between donor and the patient did not significantly affect the neutrophil and platelet (PLT) engraftment time (P = 0.389, 0.349, respectively), packed red blood cells transfusion requirement, and duration of initial hospital stay. However, patients of ABO-incompatible HSCT received more PLT transfusions posttransplant which was statistically significant. 29.1% of ABO compatible and 16.7% incompatible HSCT patients developed GVHD. Mortality rates in the two groups were 16.7% and 8.3%, respectively. However, differences in both the parameters were not statistically significant.

CONCLUSION

Our study showed that ABO incompatibility does not significantly affect the outcome and should not be a limiting factor for selection of donor. Donor availability and human leukocyte antigen (HLA) matching remain the critical selection criteria.

Post-Hematopoietic Stem Cell Transplantation Immune-Mediated Anemia: A Literature Review and Novel Therapeutics

Anemia after allogeneic hematopoietic stem cell transplantation (HSCT) can be immune or non–immune mediated. Auto- or alloimmunity resulting from blood group incompatibility remains an important cause in post-HSCT immune-mediated anemia. ABO incompatibility is commonly encountered in HSCT and may lead to serious clinical complications, including acute hemolysis, pure red cell aplasia, and passenger lymphocyte syndrome. It remains controversial whether ABO incompatibility may affect HSCT outcomes, such as relapse, nonrelapse mortality, graft-versus-host disease, and survival. Non-ABO incompatibility is less frequently encountered but can have similar complications to ABO incompatibility, causing adverse clinical outcomes. It is crucial to identify the driving etiology of post-HSCT anemia in order to prevent and treat this condition. This requires a comprehensive understanding of the mechanism of anemia in blood group–incompatible HSCT and the temporal association between HSCT and anemia. In this review, we summarize the literature on post-HSCT immune-mediated anemia with a focus on ABO and non-ABO blood group incompatibility, describe the underlying mechanism of anemia, and outline preventive and treatment approaches.

Investigation of risk factors associated with erythrocyte engraftment after ABO-incompatible hematopoietic stem cell transplantation

ABO-incompatible hematopoietic stem cell transplantations (HSCTs) are widely practiced; however, the delay in erythrocyte engraftment can be problematic. While erythrocyte engraftment is usually indicated by an increase in reticulocyte levels without the need for erythrocyte transfusions, the disappearance of recipient-derived anti-A/B isoagglutinin and detection of donor-derived A/B antigens can also be used as other parameters. We conducted a retrospective analysis of 68 ABO-incompatible HSCTs, focusing on major and bidirectional mismatch. We analyzed known clinical risk factors associated with delayed erythrocyte engraftment using the three parameters (disappearance of anti-A/B isoagglutinin in recipient, detection of donor-derived A/B antigen, and reticulocyte levels >1%). Although the three parameters were well correlated, the results showed heterogeneity when analyzing the associated risk factors for delayed erythrocyte engraftment. In the analysis of all cases, the requirement for an HLA-matched platelet transfusion was a common risk factor. Furthermore, erythrocyte engraftment was slower in adults than in children. In adults, cytomegalovirus antigenemia was a risk factor for two parameters; however, in children, underlying disease was a common risk factor for all parameters. There is a complex relationship between erythrocyte engraftment and various factors related to HSCTs. Our results suggest that greater accuracy is possible by using analysis methods other than the measurement of reticulocyte levels.

Modeling Long-Term Erythropoietic Recovery After Allogeneic Stem Cell Transplants in Pediatric Patients

Long term erythropoietic reconstitution after allogeneic hematopoietic stem cell transplantation (alloHSCT) has not been extensively studied. We aimed to describe erythropoietic reconstitution as an indicator of long-term graft function by modeling hemoglobin levels during the first 3 years post HSCT in pediatric patients. We retrospectively included 414 patients and 11,957 measurements. The largest hemoglobin increase was at day 45 and levels reached a steady state at day 648 with a level of 7.48 mmol/L. In patients transplanted for hematological malignancies hemoglobin levels normalized faster (p < 0.0001). Increasing patient age correlated with faster recovery (p < 0.0001), while donor age had no influence. Conditioning, donor type and graft source did not influence recovery significantly. In the ABO mismatched group there was a transient negative effect on hemoglobin levels, and a delay in reticulocyte recovery (21 vs. 19 days; p = 0.012). In contrast, hemoglobin levels reached a higher plateau beyond 9 months in these patients (p < 0.0001). After alloHSCT, experiencing a CMV reactivation negatively affected reconstitution (p = 0.034), while EBV reactivations and acute graft vs. host disease did not. In summary, erythropoietic recovery was mainly influenced by patient factors and primary disease, and less influenced by donor factors.

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.

Assessing the impact of ABO incompatibility on major allogeneic hematopoietic stem cell transplant outcomes: a prospective, single-center, cohort study

Background

ABO blood group incompatibility between donor and recipient is associated with a number of immunohematological complications, but is not considered a major contraindication to allogeneic hematopoietic stem cell transplantation. However, available evidence from the literature seems to be conflicting as to the impact of incompatibility on overall survival, event-free survival, transplant-related mortality, graft-versus-host disease, and time to neutrophil and platelet engraftment.

Methods

This single-center, prospective, cohort study included patients with hematological malignancies who underwent a first allogeneic hematopoietic stem cell transplantation between 2008 and 2014. Patients receiving umbilical cord blood as the stem cell source were excluded from this analysis. The impact of ABO incompatibility was evaluated in respect to overall survival, event-free survival, transplant-related mortality, acute graft-versus-host disease and engraftment.

Results

A total of 130 patients were included of whom 78 (60%) were males. The median age at transplant was 36 (range: 2–65) years, 44 (33%) presented ABO incompatibility, 75 (58%) had acute leukemia, 111 (85%) had a related donor, 100 (77%) received peripheral blood hematopoietic stem cells as graft source and 99 (76%) underwent a myeloablative conditioning regimen. There was no statistically significant association between ABO incompatibility and overall survival, event-free survival, transplant-related mortality, grade II–IV acute graft-versus-host disease, neutrophil or platelet engraftment in multivariate analysis.

Conclusion

These results show that ABO incompatibility does not seem to influence these parameters in patients undergoing allogeneic hematopoietic stem cell transplantation.

Infusion hemolysis after pediatric major ABO-mismatched bone marrow transplant: Comparison of two red blood cell depletion techniques

BACKGROUND

During major ABO-mismatched bone marrow transplant (BMT), the infusion of incompatible red blood cells (RBCs) that are present in the bone marrow graft can cause adverse events from hemolysis. RBC depletion of the bone marrow graft can decrease this risk, but the optimal method to prevent hemolysis is unclear.

PROCEDURE

We conducted a retrospective cohort study of patients who underwent major ABO-mismatched BMT at a pediatric center and had RBC depletion with either hydroxyethyl starch (HES) sedimentation or Ficoll density gradient separation. Postinfusion hemoglobinuria and creatinine values were compared.

RESULTS

Between 2002 and 2016, 37 patients received HES-treated and 16 patients received Ficoll-treated major ABO-mismatched bone marrow grafts. The median residual volume of RBCs was significantly greater with HES-treated grafts (HES 21.0 ml vs. Ficoll 1.4 ml, P < 0.0001). Patients who received HES-treated grafts had a higher prevalence of postinfusion hemoglobinuria (HES 57% vs. Ficoll 6%, P = 0.0009), but renal impairment was rare. Considering only HES-treated grafts, the volume of RBCs was not associated with either postinfusion hemoglobinuria or a creatinine increase.

CONCLUSIONS

Ficoll density gradient separation achieves smaller RBC volumes and less postinfusion hemoglobinuria than HES sedimentation, but both can prevent significant hemolysis. Further studies are needed to determine the residual incompatible RBC volume threshold in major ABO-mismatched BMT.

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.

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.

Major ABO incompatible BMT in children: determining what residual volume of donor red cells can safely be infused following red cell depletion

Major ABO incompatible BM transplantation carries a risk of acute haemolysis. Red cell depletion reduces this risk but not all incompatible RBC (iRBCs) are removed and in children the residual volume can be significant relative to body weight. We sought to determine the volume of iRBCs that can be safely given to children. All patients receiving fresh BM from a donor with a major ABO blood group mismatch between January 2000 and July 2013 at the Hospital for Sick Children, Toronto, were included. Seventy-eight patients were identified. The median volume of iRBCs transfused was 1.6 mL/kg (range 0.1-10.6 mL/kg). Thirty-five patients had minor haemolytic events and five patients had clinically significant adverse events. Two patients, who received 3.66 and 3.9 mL iRBCs/kg, developed renal impairment and in one case hypoxia and hyperbilirubinaemia. One patient had mild hypotension that resolved with i.v. fluid. Two patients developed hypotension secondary to sepsis and unrelated to BM infusion. Although signs of haemolysis occur, with appropriate hydration and monitoring of renal function, clinically significant adverse events related to the infusion of ABO incompatible BM are rare, and, in this study, were only seen in patients receiving >3 mL/kg of iRBCs per kg.

Transfusion issues in cancer patients

Allogeneic blood transfusion (ABT) therapy plays a major role in the case of patients with cancer. Packed red blood cells (PRBC) are given for increased oxygen-carrying capacity, platelets concentrates (PC) and fresh frozen plasma (FFP) for the cessation and prevention of bleeding due to thrombocytopenia and other defects of hemostasis associated with neoplasia. All these blood components can induce complications and/or adverse reactions in cancer patients including transfusion-associated graft versus host disease (TA-GVHD), transfusion transmitted diseases, alloimmunization to blood cell antigens, pulmonary decompensation, immunomodulation. Therefore, specific modifications such as leukocyte-reduction and irradiation of the blood components to be transfused in cancer patients should be introduced to reduce the risk of these complications. Patients undergoing hematopoietic progenitor cell (HPC) transplantation are a unique group and present complex concerns related to transfusion, including major and minor ABO incompatibility and chimeric blood cells. Therefore, transfusion for patients undergoing treatment with cellular therapies requires careful blood component selection. The process of HPC infusion itself carries many risks including DMSO toxicity and hemolytic reactions. In all areas of transfusion therapy, new advances such as pathogen inactivation and synthetic alternatives to blood components should help to increase the safety and tolerance of transfusion in cancer patients.

The impact of early CD4+ lymphocyte recovery on the outcome of patients who undergo allogeneic bone marrow or peripheral blood stem cell transplantation

BACKGROUND

Different factors influence the clinical outcome of allogeneic transplants, the foremost being good immune recovery.

MATERIALS AND METHODS

The purpose of this study was to evaluate the influence of different factors, such as stem cell source, type of donor, conditioning regimen and acute graft-versus-host disease, on early lymphocyte recovery after transplantation. We then analyzed the impact of early CD4+ cell count on overall survival, transplant-related mortality and disease-related mortality.

RESULTS

Univariate analysis with Spearman's rho showed a significant correlation between early CD4+ cell recovery and overall survival, transplant-related mortality, stem cell source and type of donor. In multivariate analysis CD4+ cell count was significantly associated with (i) stem cell source, being higher in patients whose haematopoietic progenitor cells were obtained by apheresis than in those whose source of grafted cells was bone marrow, and (ii) type of donor, being higher in patients transplanted from sibling donors than in those whose graft was from an alternative donor. The ROC curve of CD4+ cell count indicated that a cut-off of 115 CD4+ cells/mL could differentiate groups with different outcomes. At 2 years follow-up, patients achieving this CD4+ cell count had significantly lower cumulative transplant-related mortality compared to patients who did not have this count (10%±4% versus 40%±8%, p=0.0026). At the 5-year follow-up, the overall survival rates were 77.5%±0.6% and 36%±7% (p=0.000) in patients with a CD4+ cell count ≥115/mL and in patients with CD4+ cell count ≤ 115/mL, respectively.

CONCLUSION

Early CD4+ cell recovery after allogeneic transplantation has a relevant impact on overall survival and transplant-related mortality and is influenced by two factors: stem cell source and type of donor.

DNA-based methods in the immunohematology reference laboratory

Although hemagglutination serves the immunohematology reference laboratory well, when used alone, it has limited capability to resolve complex problems. This overview discusses how molecular approaches can be used in the immunohematology reference laboratory. In order to apply molecular approaches to immunohematology, knowledge of genes, DNA-based methods, and the molecular bases of blood groups are required. When applied correctly, DNA-based methods can predict blood groups to resolve ABO/Rh discrepancies, identify variant alleles, and screen donors for antigen-negative units. DNA-based testing in immunohematology is a valuable tool used to resolve blood group incompatibilities and to support patients in their transfusion needs.

Evaluation of 28 Human Embryonic Stem Cell Lines for Use as Unrelated Donors in Stem Cell Therapy: Implications of HLA and ABO Genotypes

For human embryonic stem cells (hESCs) to be used clinically, it is imperative that immune responses evoked by hESCs and their derivates after transplantation should be prevented. Human leukocyte antigens (HLA) and ABO blood group antigens are important histocompatibility factors in graft rejection. HLA matching between recipient and unrelated donors, in particular, is important in improving outcomes in hematopoietic cell transplantation (HCT). We have established and successfully maintained 29 hESC lines and analyzed the HLA and ABO genotypes of these lines. HLA-A, -B, -C and -DR (DRB1) genotyping was performed by polymerase chain reaction (PCR) sequence-based typing and ABO genotyping was carried out by PCR restriction fragment length polymorphism methods. To determine what proportion of the Korean population would be covered by these cell lines in organ transplantation, 27 cell lines with HLA-A, -B, and -DR data were evaluated for HCT (cord blood) donors and 28 cell lines with HLA-DR and ABO data were evaluated for solid organ (kidney) transplantation donors, and then compared the data with those from 6,740 donated cord bloods. When 2 HLA mismatches are allowed for HCT, as currently accepted for cord blood transplantation, it was estimated that about 16% and 25% of the possible recipients can find one or more donor cell lines with ≤2 mismatches at A, B, DRB1 allele level and at A, B antigen/DRB1 allele level, respectively. When HLA-DR antigen level matching and ABO compatibility was considered for solid organ (kidney) transplantation, it was estimated that about 29% and 96% of the possible recipients can find one or more ABO-compatible donor cell lines with 0 and 1 DR mismatches, respectively. We provided the first report on the HLA and ABO genotypes of hESC lines, and estimated the degree of HLA and ABO matching in organ transplantation for the Korean population.

Impact of ABO-incompatible donor on early and late outcome of hematopoietic stem cell transplantation

ABO incompatibility is not a barrier to allogeneic hematopoietic stem cell transplantation (HSCT). However, the impact of an ABO mismatch on the outcome of the HSCT remains controversial. We analyzed whether ABO incompatibility leads to an increased risk of early/late complications, mortality, or increased transfusion requirements. The 147 consecutive allogeneic HSCTs includes 80 ABO-identical and 25 major, 30 minor, and 12 bidirectional ABO-mismatched grafts. The four groups were balanced with respect to disease status at transplantation. Transplantation-related mortality was significantly greater (P < .01) and overall survival significantly shorter (P = 0.2) among HSCT recipients with minor ABO-mismatched grafts. The relapse rate, progression-free survival, and transfusion requirements until discharge were not different between ABO-identical and ABO-mismatched groups. Pure red cell aplasia (PRCA); (P < .0001) and delayed red blood cell (RBC) engraftment (P < .001) were more frequent in HSCT recipients with major mismatched donors. Delayed RBC engraftment was associated with posttransplantation hyperferritininemia and increased mortality risk (P = .05). The greater frequency of sinusoidal obstruction syndrome and graft-versus-host disease (GVHD) in patients with minor mismatched transplants, did not show statistical significance. In contrast severe GVHD was significantly more frequent among minor mismatched patients (P = .04). ABO-mismatched HSCT might have an unfavorable impact on transplant outcomes. Selection of ABO-compatible donors when possible, strategies to prevent and treat PRCA, modifications in transfusion practice, and effective iron chelation are among the measures that can improve transplant outcomes.

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.

Pediatric transfusion medicine: development of a critical mass

Many significant events have occurred in the recent past that beg a broad audience to address the question "What is pediatric transfusion medicine?" Herein, we list some of these events and their relevance below and attempt to provide an answer for this question. Indeed, several issues regarding the subspecialty of pediatric transfusion medicine (PTM) are particularly timely, and it appears that a critical mass, or a nidus capable of becoming a critical mass, is developing in PTM.