Rh antibodies against the pretransplant red cells following Rh-incompatible bone marrow transplantation

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.

[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.

Platelet transfusion - the art and science of compromise

SUMMARY

Many modern therapies depend on platelet (PLT) transfusion support. PLTs have a 4- to 7-day shelf life and are frequently in short supply. In order to optimize the inventory PLTs are often transfused to adults without regard for ABO compatibility. Hemolytic reactions are infrequent despite the presence of 'high titer' anti-A and anti-B antibodies in some of the units. Despite the low risk for hemolysis, some centers provide only ABO identical PLTs to their recipients; this practice might have other beneficial outcomes that remain to be proven. Strategies to mitigate the risk of hemolysis and the clinical and laboratory outcomes following ABO-matched and mismatched transfusions will be discussed. Although the PLTs themselves do not carry the D antigen, a small number of RBCs are also transfused with every PLT dose. The quantity of RBCs varies by the type of PLT preparation, and even a small quantity of D+ RBCs can alloimmunize a susceptible D- host. Thus PLT units are labeled as D+/-, and most transfusion services try to prevent the transfusion of D+ PLTs to D- females of childbearing age. A similar policy for patients with hematological diseases is controversial, and the elements and mechanisms of anti-D alloimmunization will be discussed.

Anti-D alloimmunization after D-mismatched allogeneic hematopoietic stem cell transplantation in patients with hematologic diseases

BACKGROUND

The de novo development of anti-D after D-mismatched allogeneic hematopoietic stem cell transplantation (AHSCT) is a possibility that must be considered. The transfusion of D- blood components after AHSCT has been recommended but anti-D alloimmunization in this setting has been studied little. Thus, the aim of this study was to analyze anti-D formation after D-mismatched AHSCT.

STUDY DESIGN AND METHODS

Thirty patients with a hematologic disease who underwent D-mismatched AHSCT were retrospectively studied. Support therapy included red blood cells (RBCs) and platelet (PLT) concentrates (PCs) from whole-blood donations and PLTs from apheresis. After AHSCT, patients received D+ PCs without administering Rh immunoglobulin (RhIG). An antibody screening to detect anti-D was performed by low-ionic-strength saline-indirect antiglobulin test with the tube test.

RESULTS

Fifteen D+ patients received stem cells (SCs) of D- donors and 15 D- patients received SCs of D+ donors. After AHSCT, patients received a median of 11.5 (range, 0-32) D- RBC units. D+ patients received 682 (83%) of 825 PLT units from D+ donors, and D- patients received 573 (85%) of 678 PLT units from D+ donors. None of the 30 patients developed anti-D after a median follow-up of 32 weeks (range, 4-310 weeks).

CONCLUSION

Anti-D alloimmunization after performing a D-mismatched AHSCT is infrequent in patients with hematologic diseases although patients receive D-mismatched PLT transfusions without RhIG administration.

Immune hemolysis associated with transplantation

Immune hemolysis is one of the adverse effects that can occur following hematopoietic cell or solid organ transplantation. Understanding the clinical settings and the various causes of immune hemolysis is necessary for prompt diagnosis and appropriate management. One of the important causes is the passenger lymphocyte syndrome, which occurs following minor ABO blood group incompatibility between donor and recipient. Hemolysis in this syndrome is often modest in severity but may be severe and even life-threatening. Major ABO blood group incompatibility is also associated with hemolysis, although this is relatively unusual and generally not severe. Autoimmune hemolytic anemia is a relatively common late complication of allogeneic transplantation and carries significant risk of mortality. Also, alloantibodies may be produced by engrafted cells of the donor's immune system or by residual cells of the patient's immune system following hematopoietic cell transplantation. Hemolysis may occur after solid organ transplantation, particularly as part of the passenger lymphocyte syndrome.

ABO-incompatible bone marrow transplantation: a GITMO survey of current practice in Italy and comparison with the literature

ABO incompatibility is not considered a contraindication for allogeneic haematopoietic stem cell transplantation (HSCT) despite its association with several immunohaematological complications. At present, there is no general agreement concerning the best methods to reduce these problems. To survey current practice related to ABO-incompatible HSCT in Italy, a questionnaire was sent to all GITMO centres. Specific questions were addressed for management in pretransplant, peritransplant and post transplant phases. A comparison was made with the experience reported in the literature. In all, 74% of GITMO centres answered the questionnaire. A high degree of heterogeneity concerning the pretransplant tests, methods to overcome infusion of ABO-incompatible marrow and post transplant transfusion policy and monitoring was evident. For many of these aspects the literature does not contain unanimous guidelines. The considerable degree of heterogeneity that reflects, at least partially, the lack of consensus in the literature demonstrates that ABO incompatibility is still an open issue in the setting of HSCT and that further studies are needed for a more rationale approach and for the production of evidence-based guidelines.

Non-ABO red blood cell alloantibodies following allogeneic hematopoietic stem cell transplantation

Immune-mediated hemolysis is a well-recognized occurrence which complicates the period following a bone marrow transplant (BMT). However, although many studies have investigated the hemolytic anemia following ABO-incompatible BMT, data regarding the occurrence of alloantibodies against red blood cell (RBC) antigens other than ABO in patients undergoing hematopoietic stem cell transplantation are limited. In this review, we briefly analyze the most important non-ABO red blood cell (RBC) antigen systems involved in the development of post-BMT alloimmune hemolytic anemia, paying particular attention to the pathogenic mechanisms and the clinical significance of the alloantibodies involved. Among the non-ABO RBC antigens, RhD antigen is the one most frequently implicated in the development of post-BMT alloimmune hemolytic anemia. Although less frequent than hemolysis following transplants with ABO incompatibility, non-ABO-incompatible allograft hemolysis may severely complicate the post-BMT period creating difficult clinical management issues. For this reason, we advise careful pre-transplant donor and recipient checks for the most important RBC antigen systems and close post-BMT immunohematological monitoring in those patients undergoing allogeneic hematopoietic stem cell transplant with RBC antigen incompatibility.

Immunohematological aspects of bone marrow transplantation

Allogeneic bone marrow transplantation (BMT) is an effective treatment for some severe hematologic or nonhematologic diseases. The blood group antigen mismatch between donor and recipient may cause immunohematological complications during or after BMT. In this review, we analyze the ABO, Rh and other red cell antigen mismatches between donor and recipient, the main immunohematological complications and the techniques to prevent them. The data reported are derived from the experience of the authors and from the medical literature. The clinical implications of the immunohematological aspects of BMT emphasize the importance of close immunohematological monitoring in patients undergoing allogeneic BMT with ABO, Rh or other red cell antigen mismatches between donor and recipient.

Development of non-ABO RBC alloantibodies in patients undergoing allogeneic HPC transplantation. Is ABO incompatibility a predisposing factor?

BACKGROUND

Data from the appearance of RBC antibodies other than ABO in patients undergoing HPC transplantation are limited.

STUDY DESIGN AND METHODS

The incidence and specificity of non-ABO RBC alloantibodies are described in a series of 217 patients undergoing allogeneic HPC transplantation because of various hematologic malignancies.

RESULTS

Eight patients (3.7%) developed 10 antibodies after transplant. None of these patients had previously been immunized. Seven patients had one RBC antibody and one patient had three RBC antibodies. Antibody specificity were anti-Jk(b) (2 patients), -Kell (2), -M (2), -Le(b) (1), and -D (1). Finally, two patients had a panagglutinin. The mean time between transplant and antibody detection was 23 days (range, 16-672). The source of the HPCs, the conditioning regimen administered, and the type of GVHD prophylaxis administered did not influence the rate of antibody formation. On multivariate analysis, ABO blood group incompatibility (p = 0.005) and patient's age (p = 0.02) were the only two variables significantly associated with the development of RBC alloantibodies.

CONCLUSION

Patients undergoing allogeneic HPC transplantation are at risk of developing RBC-specific antibodies despite the immunosuppressive therapy administered. Antibody formation was more frequently observed in ABO-mismatched cases, which suggests a potential role of this incompatibility in facilitating antibody production.

Passenger lymphocyte syndrome with severe hemolytic anemia due to an anti-Jk(a) after allogeneic PBPC transplantation

BACKGROUND

After allogeneic peripheral blood progenitor cell (PBPC) transplantation, a patient developed a severe hemolytic transfusion reaction due to passenger lymphocyte syndrome.

CASE REPORT

A 50-year-old woman with secondary acute myeloid leukemia transforming from a myelodysplastic syndrome received an ABO-compatible PBPC graft from her HLA-identical sister. For prophylaxis of GVHD, the patient was treated with cyclosporine and methotrexate. Eighteen days after the transplant, the patient experienced a severe hemolytic transfusion reaction due to an alloantibody (anti-Jk(a)) produced by donor lymphocytes.

RESULTS

The patient was typed as group A, Jk(a+) before transplantation; the donor was typed as group A, Jk(a-). On Day 18 after transplantation, the immunohematologic screening revealed a positive DAT (C3d 3+) and an alloanti-Jk(a). Hemolysis in the patient at that time was indicated by a drop in the Hb and an increase in the LDH level (maximum, 592 IU/L on Day 23).

CONCLUSION

The course of hemolysis and the time of appearance of an alloantibody in this patient meet the criteria for passenger lymphocyte syndrome. In most cases, this syndrome is triggered by ABO system antibodies. This is the first reported case of passenger lymphocyte syndrome after PBPC transplantation that was due to an alloantibody that did not belong to the ABO system.

Multiple red blood cell antibodies produced by donor B lymphocytes after ABO-matched allogeneic bone marrow transplantation

A 50-year-old man with AML[M2,t(8;21)] underwent BMT from his younger sister. At that time, he had no unexpected antibody and his blood type was O(+), CcDEe. The type of Kidd was not examined. The donor's blood type was O(+), CCDee, Jk(a+b-). One year after the BMT, the patient's blood type had changed to that of the donor's and anti-E antibody was detected. Despite the use of platelet concentrates (PCs) only, anti-c antibody was later identified. We conclude that there is a need to check red cell antibodies at regular intervals, even when using PCs only, for earlier detection of unexpected antibodies after BMT.

Intravenous anti-D gammaglobulin for the prevention of rhesus isoimmunization caused by platelet transfusions in patients with malignant diseases

Previous studies of sensitization to RhD by RhD-positive platelet transfusions in RhD-negative cancer patients have shown different frequencies of alloimmunization (max. 19%). We studied 37 RhD-negative patients who received RhD-incompatible platelet transfusions and simultaneously anti-D-immune globulin. We provide evidence that in this setting RhD-prophylaxis is highly effective in preventing alloimmunization due to RhD antigen, since none of the patients studied developed anti-D. Detection of other red blood cell antibodies than anti-D proves the possibility of immunization in these patients. Prevention of isoimmunization in patients with malignant diseases is recommended especially in young females, since an increasing number of patients are having successful pregnancies, despite prior or even during cytotoxic therapy.

Low rate of Rhesus immunization from Rh-incompatible blood transfusions during liver and heart transplant surgery

Transfusion of one unit or more of Rh-positive red blood cells normally causes circulating anti-D antibody to appear 2-6 months later in 80-95% of Rh- persons. We asked whether transplant immunosuppression with cyclosporine and corticosteroids affects Rh immunization. Nineteen Rh- liver, heart, and heart-lung transplant recipients received 3-153 (median: 10) units of Rh+ RBCs at surgery and were tested for anti-D greater than 2 months later. Three patients developed anti-D at 11-15 days; one may have had an unusually rapid primary immune response and two were secondary to previous exposure by pregnancy. None of the other 16 patients had anti-D when tested 2.5-51 months later (13 patients, greater than 11.5 months). This low rate of Rhesus immunization in association with cyclosporine immunosuppression allows greater flexibility in meeting the transfusion needs of Rh- liver and heart transplant patients. Caution is still advised in young females and in patients who may have been previously exposed to Rh+ RBCs by transfusion or by pregnancy prior to the availability of perinatal Rh immune globulin twenty years ago. Other humoral immune responses to some vaccines or infectious agents may also be impaired in transplant patients.