rss_2.0Immunohematology FeedSciendo RSS Feed for Immunohematology Feed anti-c in a D– patient prompted lifesaving work between a transfusion service and a blood center reference laboratory<abstract> <title style='display:none'>Abstract</title> <p>This case report showcases an extraordinary collaboration to support the transfusion needs of a patient with a rare phenotype and long-standing anemia due to gastrointestinal bleeding. This report describes the Immunohematology Reference Laboratory testing and logistics of rare blood provision over an 11-year period, as well as a summary of the hematologic, gastroenterologic, and surgical interventions. This case illustrates how a strong collaboration among the clinical team, laboratory, blood center, and the rare donor community facilitated successful management of this patient’s anemia until the patient could receive life-changing treatment.</p> </abstract>ARTICLEtrue and why is red blood cell genotyping applicable in transfusion medicine: a systematic review of the literature<abstract> <title style='display:none'>Abstract</title> <p>This review aims to provide a better understanding of when and why red blood cell (RBC) genotyping is applicable in transfusion medicine. Articles published within the last 8 years in peer-reviewed journals were reviewed in a systematic manner. RBC genotyping has many applications in transfusion medicine including predicting a patient’s antigen profile when serologic methods cannot be used, such as in a recently transfused patient, in the presence of autoantibody, or when serologic reagents are not available. RBC genotyping is used in prenatal care to determine zygosity and guide the administration of Rh immune globulin in pregnant women to prevent hemolytic disease of the fetus and newborn. In donor testing, RBC genotyping is used for resolving ABO/D discrepancies for better donor retention or for identifying donors negative for high-prevalence antigens to increase blood availability and compatibility for patients requiring rare blood. RBC genotyping is helpful to immunohematology reference laboratory staff performing complex antibody workups and is recommended for determining the antigen profiles of patients and prospective donors for accurate matching for C, E, and K in multiply transfused patients. Such testing is also used to determine patients or donors with variant alleles in the Rh blood group system. Information from this testing aides in complex antibody identification as well as sourcing rare allele-matched RBC units. While RBC genotyping is useful in transfusion medicine, there are limitations to its implementation in transfusion services, including test availability, turn-around time, and cost.</p> </abstract>ARTICLEtrue national survey of current immunohematologic testing practices for the diagnosis of autoimmune hemolytic anemia in India<abstract> <title style='display:none'>Abstract</title> <p>Autoimmune hemolytic anemia (AIHA) is a common term for several disorders that differ from one another in terms of etiology, pathogenesis, clinical features, and treatment. Management of patients with AIHA has become increasingly evidence-based in recent years. While this development has resulted in therapeutic improvements, it also carries increased requirements for optimal diagnosis using more advanced laboratory tests. Unfortunately, limited data are available from developing countries regarding the testing and transfusion management of patients with AIHA. The main objective of this survey was to explore the current immunohematologic testing practices for the diagnosis of AIHA in India. This online survey consisted of 30 questions, covering the place of work, the number of AIHA cases encountered in the 3 preceding years, testing method(s), transfusion management, and so forth. Individuals representing 89 laboratories completed the survey; only 78 of which responded that AIHA testing was performed in their facility’s laboratory. The majority of respondents agreed that the most commonly affected age-group comprised individuals of older than 20 years, with a female preponderance. Regarding transfusion management, respondents indicated that transfusion with “best-match” red blood cell units remains the most common practice. Column-agglutination technology is used by 92 percent of respondents as the primary testing method. Although a monospecific direct antiglobulin test is available at 73 percent of the sites, most of them have limited access to other resources that could diagnose cold or mixed AIHA. Merely 49 percent of responding laboratories have the resources to perform adsorption studies for the detection of alloantibodies. Furthermore, three-cell antibody screening reagents are unavailable at 32 percent of laboratories. In 72 percent of centers, clinical hematologists would prefer to consult a transfusion medicine specialist before administering treatment to AIHA patients. There is unanimous agreement regarding the need for a national registry. The survey data indicate wide variability in testing practices for patients with AIHA in India. Future studies are needed to focus on the feasibility and cost-effectiveness of different testing strategies for developing countries.</p> </abstract>ARTICLEtrue patient with anti-f in India identified by extensive immunohematologic workup<abstract> <title style='display:none'>Abstract</title> <p>Anti-f is produced by exposure to the compound antigen ce (f) on red blood cells (RBCs), expressed when both c and e are present on the same protein (<italic>cis</italic> position). Although anti-f was discovered in 1953, there are few cases reported worldwide because the presence of anti-f is often masked by anti-c or anti-e and is not generally found as a single antibody. In the present case, anti-f was identified by using three-cell screening and 11-cell identification panels. The identification of anti-f was further supported by additional testing, including (1) Rh antigen typing; (2) antibody identification panels (enzyme-treated panel [ficin] and an in-house–constructed Rh panel); (3) look-back and phenotyping of donor RBC units, which were responsible for alloimmunization; and (4) molecular testing of the patient’s RBCs.</p> </abstract>ARTICLEtrue profiling of D variants in donor routine: unveiling the impact on false-negative results and alloimmunization<abstract> <title style='display:none'>Abstract</title> <p>The high number of D variants can lead to the unnecessary use of Rh immune globulin, overuse of D− RBC units, and anti-D allommunization. D variant prevalence varies among ethnic groups, and knowledge of the main variants present in a specific population, their behavior in serologic tests, and their impact on clinical practice is crucial to define the best serologic tests for routine use. The present study aimed to explore the serologic profile of D variants and to determine which variants are most associated with false-negative D typing results and alloimmunization. Donor samples were selected in two study periods. During the first period, D typing was performed on a semi-automated instrument in microplates, and weak D tests were conducted in tube or gel tests. In the second period, D typing was carried out using an automated instrument with microplates, and weak D tests were performed in solid phase. Samples from patients typed as D+ with anti-D were also selected. All samples were characterized by molecular testing. A total of 37 <italic>RHD</italic> variants were identified. Discrepancies and atypical reactivity without anti-D formation were observed in 83.4 percent of the samples, discrepant D typing results between donations were seen in 12.3 percent, and D+ patients with anti-D comprised 4.3 percent. DAR1.2 was the most prevalent variant. Weak D type 38 was responsible for 75 percent of discrepant samples, followed by weak D type 11, predominantly detected by solid phase. Among the D variants related to alloimmunization, DIVa was the most prevalent, which was not recognized by serologic testing; the same was true for DIIIc. The results highlight the importance of selecting tests for donor screening capable of detecting weak D types 38 and 11, especially in populations where these variants are more prevalent. In pre-transfusion testing, it is crucial that D typing reagents demonstrate weak reactivity with DAR variants; having a serologic strategy to recognize DIVa and DIIIc is also valuable.</p> </abstract>ARTICLEtrue screening to guide antenatal anti-D immunoprophylaxis in non-immunized D– pregnant women<abstract> <title style='display:none'>Abstract</title> <p>In pregnancy, D– pregnant women may be at risk of becoming immunized against D when carrying a D+ fetus, which may eventually lead to hemolytic disease of the fetus and newborn. Administrating antenatal and postnatal anti-D immunoglobulin prophylaxis decreases the risk of immunization substantially. Noninvasive fetal <italic>RHD</italic> genotyping, based on testing cell-free DNA extracted from maternal plasma, offers a reliable tool to predict the fetal RhD phenotype during pregnancy. Used as a screening program, antenatal <italic>RHD</italic> screening can guide the administration of antenatal prophylaxis in non-immunized D– pregnant women so that unnecessary prophylaxis is avoided in those women who carry a D– fetus. In Europe, antenatal <italic>RHD</italic> screening programs have been running since 2009, demonstrating high test accuracies and program feasibility. In this review, an overview is provided of current state-of-the-art antenatal <italic>RHD</italic> screening, which includes discussions on the rationale for its implementation, methodology, detection strategies, and test performance. The performance of antenatal <italic>RHD</italic> screening in a routine setting is characterized by high accuracy, with a high diagnostic sensitivity of ≥99.9 percent. The result of using antenatal <italic>RHD</italic> screening is that 97–99 percent of the women who carry a D– fetus avoid unnecessary prophylaxis. As such, this activity contributes to avoiding unnecessary treatment and saves valuable anti-D immunoglobulin, which has a shortage worldwide. The main challenges for a reliable noninvasive fetal <italic>RHD</italic> genotyping assay are low cell-free DNA levels, the genetics of the Rh blood group system, and choosing an appropriate detection strategy for an admixed population. In many parts of the world, however, the main challenge is to improve the basic care for D– pregnant women.</p> </abstract>ARTICLEtrue of transcription factors KLF1 and GATA1 on red blood cell antigen expression: a review<abstract> <title style='display:none'>Abstract</title> <p>KLF transcription factor 1 (KLF1) and GATA binding protein 1 (GATA1) are transcription factors (TFs) that initiate and regulate transcription of the genes involved in erythropoiesis. These TFs possess DNA-binding domains that recognize specific nucleotide sequences in genes, to which they bind and regulate transcription. Variants in the genes that encode either KLF1 or GATA1 can result in a range of hematologic phenotypes—from benign to severe forms of thrombocytopenia and anemia; they can also weaken the expression of blood group antigens. The Lutheran (LU) blood group system is susceptible to TF gene variations, particularly <italic>KLF1</italic> variants. Individuals heterozygous for <italic>KLF1</italic> gene variants show reduced Lutheran antigens on red blood cells that are not usually detected by routine hemagglutination methods. This reduced antigen expression is referred to as the In(Lu) phenotype. For accurate blood typing, it is important to distinguish between the In(Lu) phenotype, which has very weak antigen expression, and the true Lu<sub>null</sub> phenotype, which has no antigen expression. The International Society of Blood Transfusion blood group allele database registers <italic>KLF1</italic> and <italic>GATA1</italic> variants associated with modified Lutheran expression. Here, we review <italic>KLF1</italic> and recent novel gene variants defined through investigating blood group phenotype and genotype discrepancies or, for one report, investigating cases with unexplained chronic anemia. In addition, we include a review of the GATA1 TF, including a case report describing the second <italic>GATA1</italic> variant associated with a serologic Lu(a–b–) phenotype. Finally, we review both past and recent reports on variations in the DNA sequence motifs on the blood group genes that disrupt the binding of the GATA1 TF and either remove or reduce erythroid antigen expression. This review highlights the diversity and complexity of the transcription process itself and the need to consider these factors as an added component for accurate blood group phenotyping.</p> </abstract>ARTICLEtrue update to Kidd blood group system<abstract> <title style='display:none'>Abstract</title> <p>Since publication of the original <italic>Immunohematology</italic> review of the Kidd blood group system in 2015 (Hamilton JR. Kidd blood group system: a review. Immunohematology 2015;31:29–34), knowledge has mushroomed pertaining to gene structure, alleles causing variant and null phenotypes, clinical significance in renal transplant and hemolytic disease of the fetus and newborn, and physiologic functions of urea transporters in non-renal tissues. This review will detail much of this new information.</p> </abstract>ARTICLEtrue the transfusion needs of a patient with anti-En requires an international effort<abstract> <title style='display:none'>Abstract</title> <p>This extraordinary case showcases the identification of a rare anti-En<sup>a</sup> specificity that was assisted by DNA-based red blood cell antigen typing and collaboration between the hospital blood bank in the United States, the home blood center in Qatar, the blood center Immunohematology Reference Laboratory, as well as the American Rare Donor Program (ARDP) and the International Society for Blood Transfusion (ISBT) International Rare Donor Panel. En<sup>a</sup> is a high-prevalence antigen, and blood samples from over 200 individuals of the extended family in Qatar were crossmatched against the patient’s plasma with one compatible En(a–) individual identified. The ISBT International Rare Donor Panel identified an additional donor in Canada, resulting in a total of two En(a–) individuals available to donate blood for the patient.</p> </abstract>ARTICLEtrue and performance of in-house red blood cell reagents to detect unexpected antibodies in immunized patients in Burkina Faso<abstract> <title style='display:none'>Abstract</title> <p>In sub-Saharan Africa, antibody detection tests remain inaccessible because of the high cost and limited shelf life of red blood cell (RBC) reagents. This study aimed at investigating the feasibility and performance of locally prepared RBC reagents for antibody detection in Burkina Faso. We conducted an experimental study comparing commercial RBC panels and a local panel prepared from phenotyped blood donors in Ouagadougou, Burkina Faso. Antibody detection testing was performed by the indirect antiglobulin test using a gel card filtration column in a low-ionic-strength solution. Judgment criteria were the concordance rate and the kappa agreement coefficient of results generated by the two panels. A total of 302 blood donors were phenotyped for the major antigens of the RH, KEL, MNS, FY, JK, LE, and P1PK blood group systems. From this pool of donors, we designed an RBC detection panel that was used to screen for unexpected antibodies in 1096 plasma samples from 832 patients with a history of transfusion and 264 recently delivered or pregnant women with no history of blood transfusion. A positive antibody detection test was observed in 8.1 percent of the samples using the local panel versus 6.4 percent with the commercial panels. A total of 23 samples were negative with the commercial panels and positive with the local panel, while the findings were reversed for four samples. The concordance rate was 97.5 percent, and the kappa agreement coefficient was 0.815. Our results suggest that the development of local RBC panels can be an alternative to commercial panels in countries with limited resources. It could also be a cost-effective intervention, mainly for children under 5 years of age, women of childbearing age, and pregnant women, all of whom are most at risk for malaria and sickle cell disease complications. Blood services could develop and implement appropriate strategies to make phenotyped donor pools available for the design of suitable RBC panels.</p> </abstract>ARTICLEtrue and anti-B titers, age, gender, biochemical parameters, and body mass index in Japanese blood donors<abstract> <title style='display:none'>Abstract</title> <p>It has been reported that anti-A and anti-B (ABO antibody) titers decrease with age, but little is known about the association between ABO antibody titers and physiologic/biochemical parameters such as body mass index (BMI), gamma-glutamyl transpeptidase (GGT), and total cholesterol (T-Cho). We investigated the present situation of ABO antibody titers among healthy blood donors in Japan and the physiologic/biochemical factors that may be associated with changes in ABO antibody titers. Plasma from 7450 Japanese blood donors was tested for ABO antibody titers using ABO reverse typing reagents by an automated microplate system; donor samples were classified into low, middle, and high titers according to the agglutination results obtained with diluted plasma samples. Multivariate regression analysis was performed to analyze the association between ABO antibody titers and age, gender, biochemical parameters (alanine transaminase [ALT], GGT, globulin, T-Cho, and glycosylated albumin [GA]), and BMI according to the ABO blood groups. A significant correlation between ABO antibody titers and age/gender, except for gender in anti-A of blood group B donors, was observed. BMI showed significant but negative correlations with anti-A and anti-B (β = −0.085 and −0.062, respectively; <italic>p</italic> &lt; 0.01) in blood group O donors. In addition, significant but negative correlations between GGT and T-Cho with anti-B of blood group A donors (β = −0.055 and −0.047, respectively; <italic>p</italic> &lt; 0.05) were observed. Although differences existed among the ABO blood groups, ABO antibody titers seem to be associated with physiologic and biochemical parameters of healthy individuals.</p> </abstract>ARTICLEtrue Patricia Tippett (1930–2023) contributors to the 2023 issues of solid-phase red cell adherence and microcolumn agglutination technology using untreated and enzyme-treated red blood cells<abstract> <title style='display:none'>Abstract</title> <p>Screening for clinically significant antibodies is crucial in transfusion medicine and is a routine part of pre-transfusion testing. The indirect antiglobulin test (IAT) is the most reliable and effective test for detecting clinically significant alloantibodies reacting at the antihuman globulin phase. Two of the main methods used for antibody detection and identification are solid-phase red cell adherence (SPRCA) and microcolumn agglutination technology (CAT), with or without enzyme-treated red blood cells (RBCs). This study was undertaken to detect and identify alloantibodies by performing antibody screen (ABS) and antibody identification (ABID) testing using SPRCA and CAT, with and without ficin-treated RBCs. Residual patient samples collected between 1 December 2020 and 19 May 2021 were saved, de-identified, and frozen at ≤−30°C before testing for alloantibodies. Seventy antibodies were detected in 53 samples among the 203 samples that underwent an ABS. Of those samples, 150 (73.0%) were nonreactive, 47 (23.1%) yielded positive results with both CAT and SPRCA, and six (3.0%) yielded positive ABS results with SPRCA only. Fifty-three samples that underwent ABID by both methods yielded eight samples with antibodies identified by SPRCA only. Additional enhancement of the CAT method by the use of ficin-treated RBCs was required to detect seven of the eight SPRCA-only antibodies; one sample remained nonreactive regardless. SPRCA testing detected clinically significant antibodies without the addition of enzyme-treated RBCs that was necessary in the CAT testing.</p> </abstract>ARTICLEtrue of solid-phase panreactivity with negative direct antiglobulin testing<abstract> <title style='display:none'>Abstract</title> <p>Solid-phase red cell adherence (SPRCA) is a sensitive platform for antibody detection, but nonspecific reactions may occur. One pattern of apparent nonspecific reactivity is a panagglutinin with a negative direct antiglobulin test (DAT). The purpose of this study was to define the clinical characteristics of patients with these nonspecific reactions and their associated serologic findings. Twenty patients with panreactive SPRCA testing results were identified between November 2022 and May 2023. In addition to panagglutinins, these patients had (1) a negative polyethylene glycol (PEG) antibody detection test, (2) a negative PEG autocontrol, and (3) a negative DAT. The strength of SPRCA panreactivity and the results of eluate testing (by tube and SPRCA) were studied. Clinical characteristics of patients included age, sex, and primary diagnosis. Each patient was also assessed for evidence of hemolysis. Fourteen female and six male patients were evaluated (average age 44 years). Primary diagnoses included pregnancy (<italic>n</italic> = 10), acute bleeding (<italic>n</italic> = 4), orthopedic (<italic>n</italic> = 3), and other (<italic>n</italic> = 3). There was no clinical or laboratory evidence of hemolysis. The predominant strength of SPRCA panreactivity was evenly distributed across reaction grades (1+ to 3+). Fifty-five percent of the eluates tested in PEG showed panreactivity, consistent with warm-reactive autoantibodies, while 85 percent of eluates tested by SPRCA were panreactive. Six discrepant cases, in which PEG eluate testing was negative and solid-phase eluate testing showed panreactivity, were associated with weak solid-phase plasma panreactivity (1+). In addition, the reactivity strengths of the eluates tested by SPRCA were invariably more strongly reactive than those eluates tested in PEG. Panagglutination is a distinct SPRCA-only plasma reactivity pattern. Despite a negative PEG tube and DAT, most panagglutinins are warm-reactive autoantibodies. Fortunately, these “interfering” panagglutinins do not appear to be clinically significant and are easily managed by an alternative testing method such as PEG.</p> </abstract>ARTICLEtrue D. Issitt (1933–2023) Specialist in Transfusion Science program