Red blood cell support and alloimmunization rate against erythrocyte antigens in patients undergoing hematopoietic stem cell transplantation

Transfusion Support in Hematopoietic Stem Cell Transplantation: A Contemporary Narrative Review

Hematopoietic stem cell transplantation (HSCT) is a cornerstone of modern medical practice, and can only be performed safely and effectively with appropriate transfusion medicine support. Patients undergoing HSCT often develop therapy-related cytopenia, necessitating differing blood product requirements in the pre-, peri-, and post-transplant periods. Moreover, ensuring optimal management for patients alloimmunized to human leukocyte antigens (HLA) and/or red blood cell (RBC) antigens, as well as for patients receiving ABO-incompatible transplants, requires close collaboration with transfusion medicine and blood bank professionals. Finally, as updated transfusion guidelines and novel blood product modifications emerge, the options available to the transplant practitioner continue to expand. Herein, we detail contemporary blood transfusion and transfusion medicine practices for patients undergoing HSCT.

Occult alloimmunization to the D antigen (RhD) related to graft versus host disease and its treatment

Alloimmunization to red blood cell (RBC) antigens post-allogeneic stem cell transplantation (allo-SCT) appears to be quite rare. The D antigen (RhD) is considered the most immunogenic RBC antigen with possibly a third of RhD-negative individuals exposed to RhD-positive RBC transfusions becoming alloimmunized. Though variable, most are detectable within a year of exposure, and the median time between exposure and detection is estimated to be about a month. We report the detection of anti-D in an allogeneic bone marrow transplant (allo-BMT) recipient about five years following last exposure to RhD-positive RBC.

Antibody incidence and red blood cell transfusions in patients on daratumumab

BACKGROUND

Daratumumab (Dara), an anti-CD38 monoclonal antibody for hematologic malignancies, interferes with routine blood bank testing, specifically affecting the antibody screen and identification panels. In 2016, the AABB recommended performing a baseline phenotype or genotype before a patient (Pt) begins taking anti-CD38 to avoid this interference and potential problems with transfusion. The objective of this study was to assess red blood cell (RBC) utilization and subsequent incidence of alloimmunization to the transfused RBCs in patients receiving Dara.

METHODS AND MATERIALS

We monitored 244 patients taking Dara to determine their red blood cell transfusions and incidence of clinically significant antibody formation before and following administration of Dara. Poisson generalized estimating equations with log link were used comparing the post-Dara incidence and prevalence to those prior, with significance defined as p < .05.

RESULTS

From September 1, 2015 to December 22, 2018, 244 patients on Dara were identified, of which 145 patients (59.4%) received a red blood cell transfusion. Antibody screens were performed on 97 of the 145 patients at least 2 weeks following RBC transfusion. Four of the total transfused patients (2.8% total, 4.1% patients with follow-up antibody screen testing) formed new clinically significant alloantibodies, which was not significantly different from Asare's hematologic incidence (p = .98/p = .49).

CONCLUSIONS

This study showed our patients on Dara did not form alloantibodies following RBC transfusion at a higher incidence than similar patient populations.

Integration of red cell genotyping into the blood supply chain: a population-based study

BACKGROUND

When problems with compatibility arise, transfusion services often use time-consuming serological tests to identify antigen-negative red cell units for safe transfusion. New methods have made red cell genotyping possible for all clinically relevant blood group antigens. We did mass-scale genotyping of donor blood and provided hospitals with access to a large red cell database to meet the demand for antigen-negative red cell units beyond ABO and Rh blood typing.

METHODS

We established a red cell genotype database at the BloodCenter of Wisconsin on July 17, 2010. All self-declared African American, Asian, Hispanic, and Native American blood donors were eligible irrespective of their ABO and Rh type or history of donation. Additionally, blood donors who were groups O, A, and B, irrespective of their Rh phenotype, were eligible for inclusion only if they had a history of at least three donations in the previous 3 years, with one donation in the previous 12 months at the BloodCenter of Wisconsin. We did red cell genotyping with a nanofluidic microarray system, using 32 single nucleotide polymorphisms to predict 42 blood group antigens. An additional 14 antigens were identified via serological phenotype. We monitored the ability of the red cell genotype database to meet demand for compatible blood during 3 years. In addition to the central database at the BloodCenter of Wisconsin, we gave seven hospitals online access to a web-based antigen query portal on May 1, 2013, to help them to locate antigen-negative red cell units in their own inventories.

FINDINGS

We analysed genotype data for 43,066 blood donors. Requests were filled for 5661 (99.8%) of 5672 patient encounters in which antigen-negative red cell units were needed. Red cell genotyping met the demand for antigen-negative blood in 5339 (94.1%) of 5672 patient encounters, and the remaining 333 (5.9%) requests were filled by use of serological data. Using the 42 antigens represented in our red cell genotype database, we were able to fill 14,357 (94.8%) of 15,140 requests for antigen-negative red cell units from hospitals served by the BloodCenter of Wisconsin. In the pilot phase, the seven hospitals identified 71 units from 52 antigen-negative red cell unit requests.

INTERPRETATION

Red cell genotyping has the potential to transform the way antigen-negative red cell units are provided. An antigen query portal could reduce the need for transportation of blood and serological screening. If this wealth of genotype data can be made easily accessible online, it will help with the supply of affordable antigen-negative red cell units to ensure patient safety.

FUNDING

BloodCenter of Wisconsin Diagnostic Laboratories Strategic Initiative and the NIH Clinical Center Intramural Research Program.

Red blood cell alloimmunization in 184 patients with myeloid neoplasms treated with azacitidine - A retrospective single center experience

Alloimmunization to Red Blood Cell (RBC) antigens frequently occurs in patients with myeloid neoplasms (AML, MDS and CMML) and potentially poses the patient at risk for delayed hemolytic transfusion reactions and limited supply of compatible RBC-units. However, there is comparatively little data on transfusion associated characteristics in this patient cohort. We therefore retrospectively analyzed transfusion requirements and clinical outcomes of 184 patients with myloid neoplasms treated with azacitidine at the Paracelsus Medical University Salzburg, which were included in the Austrian Registry of Hypomethylating Agents. The mean blood component requirements for AML, MDS and CMML were 39.8, 67.4 and 31.4 RBC units and 31.7, 27.6 and 19.1 platelet (PLT) units respectively. In spite of an extended and stringent RBC unit matching policy (ABO, RhD, RhCcEe and K antigens), 20 (11%) patients formed at least one alloantibody ("allo-group"), whereas 164 patients (89%) did not ("non-allo-group"). The most frequent antibody specificity was anti-E, followed by anti-Wra -Lua, -D, -C and -Jka. Alloimmunization was associated with higher numbers of transfused RBC units (68 vs. 38; p=0.001), as well as with longer time under transfusion (16.7 vs. 9.4 months; p=0.014). Median overall survival (OS) did not differ significantly between the "allo"- and "non-allo-group".

Impact of azacitidine on red blood cell alloimmunisation in myelodysplastic syndrome

BACKGROUND

The incidence of alloimmunisation in myelodysplastic syndromes (MDS) during the era of supportive treatment ranges from 9 to 56%. However, it is unknown if the widespread use of hypomethylating agents has changed the risk of immunisation. The aim of this study is to evaluate the impact of azacitidine (AZA) therapy on red blood cell (RBC) alloimmunisation in transfused patients with MDS, myelodysplastic syndromes/myeloproliferative syndromes (MDS/MPS) and secondary acute myeloid leukaemia (AML).

MATERIAL AND METHODS

We have analysed retrospectively all patients with MDS, MDS/MPS and secondary AML from MDS, who received their first transfusion in our hospital between January 1995 and December 2014. We have assessed the impact of age, sex, RBC and platelets units transfused, and AZA treatment on developing alloantibodies.

RESULTS

In our study, the number of RBC units transfused increased the risk of developing alloantibodies. However aging and the treatment with AZA were associated with a lower rate of alloimmunisation.

DISCUSSION

Patients with MDS, MDS/MPS and secondary AML who received treatment with AZA developed RBC antibodies at a lower rate than control group. We suggest that aging and immunosuppression due to AZA therapy could develop an immunological tolerance with a weak response to allotransfusions.

Transfusion of fresh murine red blood cells reverses adverse effects of older stored red blood cells

BACKGROUND

Although a subset of recent studies have suggested that red blood cell (RBC) storage length is associated with adverse patient outcomes, others have shown no such relationship. Adults may be transfused with RBC units of different storage lengths, and existing studies do not take into consideration that fresh RBCs may alter responses to concurrently transfused stored RBCs. To test this possibility, we utilized a murine model and investigated transfusion outcomes of fresh, stored, or fresh-plus-stored RBCs.

STUDY DESIGN AND METHODS

Fresh, 14-day-stored or fresh plus 14-day-stored leukoreduced RBCs from HOD-transgenic donors (with RBC-specific expression of hen egg lysozyme, ovalbumin, and human Duffy(b)) were transfused into naïve C57BL/6 recipients. Serum cytokines and anti-HOD alloimmunization were evaluated after transfusion.

RESULTS

In six of six experiments (n = 90 mice total), a proinflammatory serum cytokine storm of interleukin-6, keratinocyte-derived chemokine/CXCL1, and monocyte chemoattractant protein-1 was observed in transfusion recipients of stored but not fresh RBCs, along with high degrees of anti-HOD alloimmunization. However, concurrent transfusion of fresh HOD RBCs along with stored HOD RBCs significantly decreased these adverse outcomes (p < 0.05).

CONCLUSIONS

These results are consistent with fresh murine HOD RBCs losing protective properties during storage, and introduce a previously unrecognized variable in RBC storage studies. If translatable to humans, uniform "old blood" groups may be needed in future clinical studies to more accurately investigate the biologic effects of older RBC units.

RH genotyping in a sickle cell disease patient contributing to hematopoietic stem cell transplantation donor selection and management

African individuals harbor molecular RH variants, which permit alloantibody formation to high-prevalence Rh antigens after transfusions. Genotyping identifies such RH variants, which are often missed by serologic blood group typing. Comprehensive molecular blood group analysis using 3 genotyping platforms, nucleotide sequencing, and serologic evaluation was performed on a 7-year-old African male with sickle cell disease who developed an "e-like" antibody shortly after initiating monthly red blood cell (RBC) transfusions for silent stroke. Genotyping of the RH variant predicted a severe shortage of compatible RBCs for long-term transfusion support, which contributed to the decision for hematopoetic stem cell transplantation. RH genotyping confirmed the RH variant in the human leukocyte antigen-matched sibling donor. The patient's (C)ce(s) type 1 haplotype occurs in up to 11% of African American sickle cell disease patients; however, haplotype-matched RBCs were serologically incompatible. This case documents that blood unit selection should be based on genotype rather than one matching haplotype.

Transfusion policy: when to stop the use of extremely rare blood for an allogeneic hematopoietic progenitor cell transplant recipient with a history of red cell alloimmunization

BACKGROUND

Decisions for when to select, and when to discontinue, antigen-negative blood in hematopoietic progenitor cell transplantation (HPCT) recipients with red blood cell (RBC) antibodies can be confusing. In HPCT performed for sickle cell anemia patients who require extremely rare antigen-negative blood, the balance of caution and practicality is further complicated.

CASE REPORTS

Four sickle cell anemia patients with current or historic RBC antibodies underwent allogeneic HPC transplantation. One required extremely rare (group O D-, hr(B)-) blood. None of the antibodies caused significant hemolysis after transplant. In the case requiring rare blood, antigen-negative blood was requested after donor RBC engraftment because of incomplete donor white blood cell (WBC) chimerism.

CONCLUSIONS

RBC antibodies derived from a recipient of allogeneic HPCT rarely cause significant hemolysis, in contrast to the more severe picture sometimes seen with donor-derived antibodies. When donor WBC chimerism is delayed past the time of donor RBC engraftment, there can be concern for the possibility of future recipient-type antibody production. Even 100 percent donor lymphocyte chimerism is no guarantee of total host plasma cell ablation. Immunoglobulin allotyping, when informative, can suggest chimerism for several years. Recipient-type blood, when extremely rare, may not be available for that duration.