Rare Donor Program Research Articles

Comments on: Molecular matching of red blood cells is superior to serological matching in sickle cell disease patients

Comments on: Molecular matching of red blood cells is superior to serological matching in sickle cell disease patients

How to find, recruit and maintain rare blood donors

Since the early 1960s, it was recognized that patients with very complex serology may be limited in the availability of rare blood for transfusion. Over the years, there have been publications about the quest to meet those needs. Although the world's literature on how to find, recruit and maintain rare blood donors is not overwhelming, there are quite a few pearls. This review will seek out those pearls published in 2007-2009 and provides some insight from a perspective of having a responsibility for a nation of patients requiring rare blood for over 15 years. Most pertinent publications have focused on a particular country and the data gathered by a particular regional area or the national rare donor program. It is clear that the definition of 'rare' varies from country to country. A blood type rare in one country may not be considered rare in another. A few of the publications that will be reviewed are specific to donor recruitment or specific details regarding a particular blood type. Recently, with the advent of semi-automated equipment to assist in DNA analysis, there has been a volley of articles on the use of this equipment.Without effective rare donor programs, there is a risk that transfusion needs may not be met. Hemovigilance concentrates on adverse events related to blood transfusions, and the event that happens when rare blood is not available may be that the patient dies without the transfusion they need. The need for rare blood has been recognized for nearly 50 years, and there are some very effective programs across the world, but not all the areas of the world are equally supplied. The International Society of Blood Transfusion Working Party for Rare Donors is a vital link in the worldwide goal of providing rare blood to the patients who need it.

Frozen red blood cells: cold comfort in a disaster?

Frozen red blood cells: cold comfort in a disaster?

Molecular characterization of GYPB and RH in donors in the American Rare Donor Program

Abstract Transfusion of patients with sickle cell disease (SCD) has been a challenge in clinical transfusion medicine, especially when the required donor RBCs must be U– and negative for high-prevalence Rh phenotypes (hrB, hrS). It is now possible to genotype donors to identify or confirm Uvar and U– phenotypes, as well as Rh hrB– and hrS– phenotypes, and to characterize the different RH backgrounds found in these donors. In a preliminary study of donors registered in the American Rare Donor Program, twelve different RH backgrounds were identified in eighteen hrB– or hrS– donors. These results, summarized in the current report, confirm the heterogeneous nature of these phenotypes and are relevant for selection of donor units for patients with antibodies to high-prevalence Rh antigens. Not all phenotypically similar units will be compatible, and matching the Rh genotype of the donor to the patient is important to prevent further Rh sensitization. Most donors referred were hrB– and carry at least one hybrid RHD-CE(3-7)-D gene that encodes a variant C antigen linked to RHCE*ceS that encodes the VS+V– phenotype. Surprisingly, the majority of donors were heterozygous, some even carrying conventional alleles, suggesting that the loss of expression of the hrB epitopes on RBCs is a dominant phenotype. Although antigen-matching of patients with SCD with donors for C, E, and K antigens has decreased the incidence of alloimmunization, some patients still become immunized to Rh antigens, indicating the units were not truly matched. RH genotyping can identify those patients with SCD who carry RH alleles that encode altered C, e, or D who are at risk for production of “apparent auto” and alloantibodies to Rh antigens. RH genotyping of alloimmunized patients with SCD, partnered with genotyping of donors, can identify compatible units that would also eliminate the risk of further Rh alloimmunization. Immunohematology 2006;22:143–147.

Serologic and molecular genetic management of a pregnancy complicated by anti-Rh18

Abstract Antibodies, such as anti-Rh18 (Hr/HrS), that react with the common products of RHCE can cause HDN as well as severe hemolytic transfusion reactions. Individuals with anti-Rh18 antibodies can have different RHCE genetic backgrounds; therefore, sera and RBCs from these individuals may cross-react. In these situations, genotyping may be the best method to determine compatibility. We report a 26-year-old pregnant Puerto Rican woman who presented at 31 weeks’ gestation with anti-E and anti-Rh18 in her serum. No potential donors were identified among family members or within the American Rare Donor Program; therefore, a unit of the patient’s RBCs was collected one week before her planned caesarian section. To improve our ability to supply blood for this patient in the future, molecular testing was performed. The patient was found to be homozygous for an RH haplotype in which a variant RHD*DAR, is linked to a variant RHCE*ceAR. The DAR-ceAR haplotype has been described in Dutch-African populations, but this is the first report of an individual self-identified of Hispanic ethnicity. This case report demonstrates the clinical importance of molecular testing of patients with rare Rh phenotypes. Immunohematology 2006;22:132–135.

In search of red blood cells for alloimmunized patients with sickle cell disease

Abstract Patients with sickle cell disease (SCD) typically require transfusions with RBC components, which exposes them to numerous, possibly foreign antigens and potentially causes them to produce an antibody or antibodies to the antigens they lack. As transfusion of these patients increases, the likelihood that they will produce an initial antibody or additional antibodies increases. Once a clinically significant antibody is produced, units of RBCs that lack the associated antigen should be transfused. Often patients with SCD present to the transfusion service with numerous antibodies in their serum, making the search for compatible RBCs a challenge. The American Rare Donor Program (ARDP) has been used to search for RBCs to meet the transfusion needs of this patient population. Between January 2005 and June 2006, approximately 33 percent of the requests to the ARDP for RBC components were for alloimmunized patients with SCD. Of these requests, 94.9 percent were completely or partially filled; requests for r"r", Hy–, and E–, hrS– units of RBCs were among the most difficult to fill. This article will discuss the use and effectiveness of the ARDP and testing laboratories associated with the National Reference Laboratory for Blood Group Serology at the American Red Cross in obtaining compatible RBCs for alloimmunized patients with SCD. Immunohematology 2006;22:136–142.

Review: American Rare Donor Program

Review: American Rare Donor Program

Review: IgA anaphylactic transfusion reactions.Part I. Laboratory diagnosis, incidence, and supply of IgA-deficient products

Abstract Despite yielding a definitive diagnosis in fewer than 20 percent of anaphylactic transfusion reactions, investigation for IgA deficiency and the presence of presumably pathogenic IgG anti-IgA is useful in patient management. Individuals with demonstrated anti-IgA are thereafter committed to receiving IgA-depleted cellular products or IgA-deficient plasma and derivatives to prevent recurrent severe reactions. Unfortunately, in populations of IgA-deficient individuals screened for anti-IgA, the predictive value of the test in the absence of a prior reaction is quite low. Anti-IgA testing is complex and limited to a few reference laboratories, many of which still employ a labor-intensive hemagglutination assay developed in the late 1960s. Timely decisions regarding further transfusion management of patients experiencing anaphylaxis often rely upon more rapidly obtained assays of the IgA concentration as an indicator of the likelihood of subsequent demonstration of anti-IgA. The scarcity of IgA-deficient banked plasma products and dedicated platelet-pheresis donors has led to the development of American Rare Donor Program policies designed to appropriately allocate these precious resources. The test methods used to establish the diagnosis of IgA deficiency and identify the approximately one-third of these individuals with anti-IgA are discussed, along with the incidence of abnormal tests in various populations. Also presented are testing recommendations for the identification of an IgA-mediated mechanism for transfusion-associated anaphylaxis and qualification of patients to receive rare IgA-deficient plasmacontaining products. Immunohematology 2005;21 :226–233.

Broadening the base of a rare donor program by targeting minority populations.

Some red cell phenotypes are found exclusively in one race and may be of low frequency. Finding compatible blood for patients needing one of these rare types has been extremely difficult. A program was implemented to screen large numbers of donors for blood types found solely in their racial group. Implementation steps included obtaining broad community endorsement of the concept, educating blood service personnel, developing educational materials, enlisting the support of a knowledgeable physician from a minority group, developing a computer program to facilitate selection of donors to be tested, beginning the program and making the necessary adjustments, doing the laboratory testing to identify rare bloods, notifying the rare donors, and maintaining the enthusiasm of the entire blood service for the rare donor screening program. After 7706 black donors were typed, 1 Cr-, 5 Hy-, 24 U-, and 20 Js(b-) persons were found; one U- donor was also Js(b-).