ABO incompatibility is associated with increased non-relapse and GVHD related mortality in patients with malignancies treated with a reduced intensity regimen: a single center experience of 221 patients

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.

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.

Augmented myeloablative conditioning with thiotepa in acute myeloid leukemia - improved outcomes with similar toxicity

Myeloablative doses of busulfan (Bu) with fludarabine (Flu) have reduced toxicity, however, limited by an increased relapse rate. We aimed to improve outcome of Flu-Bu regimen by augmentation with thiotepa (TT) (10 mg/kg). Eighty-nine patients with AML, 44 patients conditioned with Flu-Bu (group 1), and 45 patients augmented with TT (Flu-Bu-TT, group 2), were retrospectively analyzed. Primary objectives were toxicity and outcomes. Major toxicities were comparable: mucositis (p = 1.0), sepsis (p = .7), severe venocclusive disease of liver (VOD) (p = 1.0), and non-relapse mortality (NRM) (22 vs. 22%, p = .7). Five-year disease-free survival was significantly better in group 2 compared to group 1 (62 vs. 38%, p = .02). Five-year overall survival (OS) showed trend toward benefit in group 2 (62 vs. 42%, p = .06). Lower relapse rate in group 2 (14 vs. 46%, p = .005) contributed to better outcomes. Augmented regimen has better disease-free survival (DFS) (mainly due to reduced relapse rate) and similar toxicities as compared to Flu-Bu. Key points  Assessing the addition of TT to myeloablative conditioning (Flu, Bu) in patients undergoing allogeneic stem cell transplant for acute myeloid leukemia with regard to relapse rate, disease-free survival and toxicity.  Addition of thiotepa improves disease-free survival and shows trend toward benefit in overall survival, by reducing relapses without additional toxicity.

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.

Development of enhancing agglutination reaction using gold nanoparticle for pre-transfusion testing

OBJECTIVES

To explore an alternative way for antibody detection testing, the examination of gold nanoparticle solution for enhancing unexpected antibodies for pre-transfusion testing was investigated.

BACKGROUND

Exposure of foreign antigens on red blood cells from transfusion can trigger the immune system to produce unexpected antibodies. This immunological response may cause the complication to future transfusion. For detection of unexpected antibodies, the antibody screening test is performed approximately 30-60 min. To reduce turnaround time, enhancing reagent, low-ionic strength solution (LISS), is widely used. However, cost of enhancing reagent is an issue which has concerned in resource limited countries. Gold nanoparticle solution can increase red blood cells agglutination reaction. To solve this issue, study of gold nanoparticle solution was investigated.

METHODS

Samples were performed comparing between LISS and gold nanoparticle solution at antiglobulin phase. After reading the agglutination reaction, supernatants were collected and measured at the optical density at 760 nm by spectrophotometer.

RESULTS

The optical density in the tube of gold nanoparticle solution was higher than in the tube of 2-5% cell suspension and monoclonal antibody. It has been observed that gold nanoparticle solution enhanced the reaction of agglutination 98% while LISS enhanced the agglutination only 60·8%. Employing a commercially available enhancing reagent, parallel samples confirmed results providing validation of the assay. It approximately costs $1 US dollars compared to $30 for a commercially available reagent.

CONCLUSIONS

The low cost and yet effective time-consuming test for antibody screening is a practical and viable solution alternative way for performing in antibody screening test in resource limited countries.

[Impacts of ABO incompatibility on early outcome after single unit unrelated cord blood transplantation: a retrospective single center experience]

OBJECTIVE

To retrospectively study the impacts of ABO incompatibility on early outcome after single unit unrelated cord blood transplantation（UCBT）, such as cumulative incidence of engraftment, incidence of acute graft- versus- host disease （aGVHD） and 180- day transplant- related mortality（TRM）.

METHODS

208 patients underwent single unit UCBT from April 2008 to October 2014 were analyzed, included 99 ABO- identical, 60 minor, 38 major and 11 bidirectional ABO- incompatible recipients. All the patients received intensified myeloablative conditioning, and a combination of cyclosporine A and mycophenolate mofetil was given for GVHD prophylaxis.

RESULTS

Cumulative incidences of neutrophil engraftment, platelet recovery, erythroid lineage reconstitution, Ⅱ-Ⅳ aGVHD, Ⅲ-Ⅳ aGVHD and 180- day TRM showed no significant difference among the patients receiving ABOidentical, minor, major, and bidirectional UCBT（all P>0.05, respectively）. What's more, none of the patients developed pure red- cell aplasia（PRCA）after UCBT. Group A donor and a group O recipient patients didn't appeared to influence the clinical results when compared with others（all P>0.05, respectively）.

CONCLUSION

Patients receive ABO- incompatible UCBT may not develop PRCA. The presence of ABO- incompatibility did not influence the hematopoietic reconstitution, the incidence of aGVHD and 180-day TRM in this cohort. There is not support for the need to regard ABO-compatibility as an UCB-graft selection criterion.

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.

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.

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.

Impact of ABO-mismatch on risk of GVHD after umbilical cord blood transplantation

Recent advances in allogeneic hematopoietic cell transplant (allo-HCT) have led to an increasing use of alternative donors, including banked umbilical cord blood (UCB). Despite these advances, acute GVHD (aGVHD) and chronic GVHD (cGVHD) continue to be the leading causes of early and late transplant-related mortality. ABO-mismatch has been frequently reported as a risk factor for GVHD, however, data in the UCB recipients are limited. We hypothesized that as the lymphocytes in the cord blood are thought to be naive, they will therefore be less likely to mediate GVHD. Therefore, we analyzed the impact of ABO-mismatch on aGVHD and cGVHD in recipients of single and double UCB-HCT. In both univariate and multivariate analyses, presence of ABO-mismatch did not have an impact on aGVHD or cGVHD. Whereas ABO-compatible donors are preferred in recipients of URD-HCT, ABO compatibility generally need not be considered in recipients of UCB-HCT.

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.

The impact of donor type and ABO incompatibility on transfusion requirements after nonmyeloablative haematopoietic cell transplantation

We retrospectively analyzed transfusion requirements within the first 100 d among allogeneic haematopoietic cell transplantation (HCT) recipients with haematological malignancies given either myeloablative (n = 1353) or nonmyeloablative conditioning (n = 503). We confirmed that myeloablative recipients required more platelet and red blood cell (RBC) transfusions than nonmyeloablative recipients (P < 0.0001 for both). Myeloablative patients given peripheral blood stem cells required less platelet transfusions (P < 0.0001) than those given marrow while RBC transfusion requirements did not differ significantly. Subsequent analyses were restricted to nonmyeloablative recipients. Platelet and RBC transfusions were less frequent among related compared to unrelated recipients (P < 0.0001 for both), with comparable median numbers of transfused units. Major/bidirectionally ABO-mismatched recipients required more RBC transfusions than ABO-matched recipients (P = 0.006). Rates of graft rejection/failure, grades II-IV acute and chronic graft-versus-host-disease (GVHD), 2-year relapse, 3-year survivals and non-relapse mortality were comparable among ABO-matched, minor-mismatched, and major/bidirectionally mismatched recipients (P = 0.93, 0.72, 0.57, 0.36, 0.17 and 0.79, respectively). Times to disappearance of anti-donor IgG and IgM isohemagglutinins among major/bidirectionally ABO-mismatched recipients were affected by magnitude of pre-HCT titres (P < 0.001 for both) but not GVHD (P = 0.71 and 0.78, respectively). In conclusion, nonmyeloablative recipients required fewer platelet and RBC transfusions and among them, both unrelated and major/bidirectionally ABO-mismatched recipients required more RBC transfusions. ABO incompatibility did not affect nonmyeloablative HCT outcomes.

Non-myeloablative allogeneic hematopoietic stem cell transplantation

OBJECTIVE

To review the literature related to nonmyeloablative stem cell transplantation (SCT), and the unique characteristics and patient population to which it applies.

DATA SOURCES

Research studies, research and clinical reviews, clinical experience.

CONCLUSION

Nonmyeloablative SCT has demonstrated effective and safe application in a heterogeneous population not otherwise eligible for an allogeneic transplantation. Although many principles are based on those of conventional myeloablative transplantation, the engraftment kinetics, patient selection, and regimen-related complications are distinct.

IMPLICATIONS FOR NURSING PRACTICE

Nurses must be knowledgeable about nonmyeloablative SCT, including the provision of individualized care for a heterogeneous population. This can include non-traditional transplant indications, elderly cancer patients, and those with comorbidities.

Prevention of pure red cell aplasia after major or bidirectional ABO blood group incompatible hematopoietic stem cell transplantation by pretransplant reduction of host anti-donor isoagglutinins

BACKGROUND

Persistent anti-donor isoagglutinins after major ABO blood group incompatible hematopoietic stem cell transplantation may cause delayed red blood cell engraftment and post-transplant pure red cell aplasia.

DESIGN AND METHODS

We investigated the effect of pretransplant anti-donor isoagglutinin reduction by in vivo absorption and/or plasmapheresis on the incidence of pure red cell aplasia and the time to red blood cell engraftment in 153 hematopoietic stem cell transplant recipients with major ABO incompatibility.

RESULTS

Twelve patients (8%) developed pure red cell aplasia, 3/98 (3%) with, and 9/55 (16%) without prior isoagglutinin reduction (p=0.009). Red blood cell engraftment was faster in patients with isoagglutinin reduction; in addition, peripheral blood hematopoietic stem cell transplantation, acute graft-versus-host disease, and younger age were associated with faster red blood cell engraftment in Cox regression analysis. In patients with pure red cell aplasia the mean red blood cell engraftment occurred after 225 days (p<0.001) and was associated with a simultaneous decrease of anti-donor isoagglutinins. Patients with pure red cell aplasia had higher pretransplant anti-donor isoagglutinin titers (p=0.001) and received more post-transplant red blood cell transfusions (p<0.001).

CONCLUSIONS

Following major ABO incompatible hematopoietic stem cell transplantation, pure red cell aplasia and delayed red blood cell engraftment depend on the levels of anti-donor isoagglutinins and are efficiently prevented by the pretransplant removal of these isoagglutinins. The benefits of reducing the time of transfusion-dependency and transfusion-associated risks must be carefully balanced against the potential side effects of isoagglutinin reduction.

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.

A review of transfusion practice before, during, and after hematopoietic progenitor cell transplantation

The increased use of hematopoietic progenitor cell (HPC) transplantation has implications and consequences for transfusion services: not only in hospitals where HPC transplantations are performed, but also in hospitals that do not perform HPC transplantations but manage patients before or after transplantation. Candidates for HPC transplantation have specific and specialized transfusion requirements before, during, and after transplantation that are necessary to avert the adverse consequences of alloimmunization to human leukocyte antigens, immunohematologic consequences of ABO-mismatched transplantations, or immunosuppression. Decisions concerning blood transfusions during any of these times may compromise the outcome of an otherwise successful transplantation. Years after an HPC transplantation, and even during clinical remission, recipients may continue to be immunosuppressed and may have critically important, special transfusion requirements. Without a thorough understanding of these special requirements, provision of compatible blood components may be delayed and often urgent transfusion needs prohibit appropriate consultation with the patient's transplantation specialist. To optimize the relevance of issues and communication between clinical hematologists, transplantation physicians, and transfusion medicine physicians, the data and opinions presented in this review are organized by sequence of patient presentation, namely, before, during, and after transplantation.