Red blood cell alloimmunization in transfusion-dependent Egyptian patients with thalassemia in a limited donor exposure program

BACKGROUND: Thalassemia is considered the most common hemoglobinopathy in Egypt and is one of its major health problems. Lifelong red blood cell (RBC) transfusion remains the main treatment for severe forms; however, RBC alloimmunization results as a complication of regular transfusions due to repeated exposure to foreign antigens. The objective was to compare the frequency of alloantibodies in a group of patients in a limited donor exposure program (LDEP) with those receiving RBCs from multiple donors in Egyptian transfusion‐dependent patients with thalassemia. STUDY DESIGN AND METHODS: A total of 235 regularly transfused patients with thalassemia were studied, 36 of which were on LDEP. All patients were investigated for the presence of RBC autoantibodies and alloantibodies, followed by antibody identification for positive patients. RESULTS: Forty‐six (19.5%) patients developed RBC alloantibodies. The most common clinically significant alloantibodies were directed against antigens in the Kell and Rh systems. Development of alloantibodies was associated with older age, higher transfusion frequency, and splenectomy. A trend toward lower alloimmunization was elicited in the LDEP group, where 8.3% (3/36) patients were alloimmunized compared to 21.6% (43/199) in the non‐LDEP one (p = 0.057). CONCLUSIONS: Examination of donor RBCs for presence of Kell and Rh(E) antigens before transfusion can help decrease RBC alloimmunization. Further larger studies are required to assess the frequency of alloantibody production in patients on LDEP.     

Red blood cell alloimmunization among sickle cell Kuwaiti Arab patients who received red blood cell transfusion

BACKGROUND: Sickle cell disease (SCD) is common in the Arabian Gulf region. Most cases require a red blood cell (RBC) transfusion, increasing the potential for RBC alloantibody development. The incidence of RBC alloimmunization among Kuwaiti Arab SCD patients is not yet known. This study retrospectively assessed the effect of using two different matching protocols on the incidence of alloimmunization among multiply transfused Kuwaiti Arab SCD patients.
STUDY DESIGN AND METHODS: A total of 233 Kuwaiti Arab SCD patients were divided into two groups: Group 1 (n = 110) received RBC transfusion through standard ABO- and D-matched nonleukoreduced blood; Group 2 (n = 123) received RBCs matched for ABO, Rh, and K1 poststorage-leukoreduced blood. Multivariate analysis was performed on the factors associated with RBC alloimmunization and antibody specificity.
RESULTS: Sixty-five percent of patients in Group 1 developed clinically significant RBC alloantibody with an increased prevalence in females; in patients in Group 2, 23.6% developed RBC alloantibodies (p = 0.01). In Group 1, 72 patients (65.5%) had alloantibodies directed against Rh and Kell systems (p = 0.01). Multivariate analysis further confirmed the results, showing that blood transfusion type and sex have significant effects on the rate of alloimmunizations.
CONCLUSION: This study confirms the importance of selecting RBCs matched for Rh and Kell to reduce the risk of alloimmunizations among Kuwaiti Arab SCD patients.     

High frequency of autoimmunization among transfusion-dependent Tunisian thalassaemia patients

Background

Limited data are available on the frequency of RBC alloimmunization and autoimmunization in transfusion-dependant Tunisian β thalassaemia patients.

Materials and methods

We analyzed the clinical and transfusion records of 130 patients (57 females and 73 males; mean age 119 months; range 12–11 months) with β thalassaemia major and who had regular blood transfusions for periods ranging from 12 to 311 months.

Results

Of the 130 patients, ten (7.7%) developed RBC alloantibodies. The most common alloantibodies were directed against antigens in the Rh systems. Erythrocyte-autoantibodies as determined by a positive direct antiglobulin Coombs test, developed in 52(40%) patients with and without underlying RBC alloantibodies, thereby causing autoimmune haemolytic anaemia in eleven patients (21%).

Conclusions

Autoimmunization to erythrocyte antigens is a frequent complication in patients with β thalassaemia major. Several factors might have contributed to the high autoimmunization rate observed in this study, including non phenotypic blood exposure and alloantibody formation prior to positive Coombs test.     

Clinically significant red blood cell antibodies in chronically transfused patients: a survey of Chinese thalassemia major patients and literature review

BACKGROUND: Red blood cell (RBC) alloimmunization is reported to occur at an incidence of 5.2% to 23.5% among patients with thalassemia requiring chronic transfusion. With very limited data on alloimmunization among the Chinese population, a territory‐wide study has been performed to look at its prevalence among Chinese thalassemia major patients. STUDY DESIGN AND METHODS: A retrospective study was conducted by reviewing RBC request records for patients with thalassemia major in Hong Kong from 2006 to 2009. Demographic information and serologic data were retrieved for analysis. RESULTS: A total of 382 patients were identified and consisted of 190 males and 192 females with a median age of 23 ± 10.4 (range, 0.25 to 52) years. Eighty‐eight patients (23.0%) were reported to have RBC antibodies. Of them, 114 alloantibodies, 18 autoantibodies, and 19 unidentified antibodies were identified. Anti‐E (42, 39.3%), anti‐Mi^a/Mur (33, 30.85%), anti‐c (14, 13.1%), and anti‐Jk^a (seven, 6.55%) were the commonest antibodies reported. However, one case of anti‐K (0.9%) and two cases of anti‐Fy^b (1.9%) were reported. Seven of the 18 patients with autoantibodies contained a total of 13 alloantibodies. They were anti‐E (five, 38.4%), anti‐Mi^a/Mur (four, 30.8%), anti‐Jk^a (two, 15.4%), anti‐c (one, 7.7%), and anti‐Fy^b (one, 7.7%). CONCLUSION: It is the first comprehensive study on Chinese thalassemia major patients. Clinically significant alloantibodies are different from those observed in the Western population, although antibodies developed against Rh antigens are still common. Chinese patients are less likely to have antibodies against Kell and Duffy blood group antigens, but are more prone to develop antibodies against the Miltenberger antigens.     

Red blood cell alloimmunization in transfused patients with myelodysplastic syndrome or chronic myelomonocytic leukemia

BACKGROUND: Red blood cell (RBC) alloimmunization is a major problem in chronically transfused patients because of the risk of hemolytic reactions and limited availability of compatible blood. This study was aimed at determining the characteristics of RBC alloimmunization in transfusion‐dependent patients with myelodysplastic syndrome or chronic myelomonocytic leukemia (MDS/CMML). STUDY DESIGN AND METHODS: The transfusion and clinical records of all patients with MDS/CMML seen at our hospital from 1990 to 2009 were reviewed. The cumulative incidence of RBC alloimmunization was calculated by taking death as a competing risk. Incidence rates were compared by Poisson multivariate regression. RESULTS: A total of 272 patients were included. Median age was 74 years; 55% were men and had received a median of 33 (range, 4‐421) RBC units. Forty‐two (15%) patients formed 81 alloantibodies and seven autoantibodies. Three additional patients developed autoantibodies without alloantibodies. The incidence rate of RBC alloimmunization was 1 per 10.5 person‐years and was independent of sex, age, and MDS diagnostic category. The cumulative incidence of alloimmunization increased with the number of RBC transfusions, reaching a plateau at 19.5% after 130 RBC units. The most common antibody specificities were Kell (26 cases), E (19), c (5), and Jk^a (5). In 26 (62%) of the 42 alloimmunized patients, only the Rh system and Kell were involved. CONCLUSION: RBC alloimmunization occurs in 15% of MDS/CMML patients on chronic transfusion support and mostly involves the Rh system and Kell. Transfusing these patients with extended antigen‐matched blood, including Kell and CcEe antigens, would presumably reduce the RBC immunization rate.     

Comparison of a gel microcolumn assay with the conventional tube test for red blood cell alloantibody titration

BACKGROUND: Titration is a semiquantitative method used to estimate red blood cell (RBC) alloantibody reactivity. The conventional tube test (CTT) technique is the traditional method for performing titration studies. The gel microcolumn assay (GMA) is also a sensitive method to detect RBC alloantibodies. The aim of this study was to compare a GMA with the CTT technique in the performance of Rh and K alloantibody titration. STUDY DESIGN AND METHODS: Patient serum samples that contained an RBC alloantibody with a singular specificity were identified by routine blood bank workflow. Parallel titration studies were performed on these samples by both the CTT method and a GMA (ID‐Micro Typing System anti‐IgG gel card, Micro Typing Systems, Inc., an Ortho‐Clinical Diagnostics Company). RESULTS: Forty‐eight samples were included, including 11 anti‐D, five anti‐c, 13 anti‐E, one anti‐C, three anti‐e, and 15 anti‐K. Overall, the two methods generated identical results in 21 of 48 samples. For 42 samples (87.5%) the two methods generated results that were within one serial dilution, and for the remaining six samples, results were within two dilutions. CONCLUSION: GMA systems may perform comparably to the CTT in titrating alloantibodies to Rh and Kell antigens.     

The HLA-DRB1*11 group-specific allele is a predictor for alloantibody production in the transfusion-dependent thalassemia patients

Background and ObjectivesRecently, researchers have shown an increased interest in thalassemia for detecting susceptible factors in alloimmunization development. Alloimmunization, especially against Rh and Kell blood, occurs in 30% of thalassemia dependent transfusion (TDT) patients. The aim of this study is to determine the role of HLA-DRB1*11 and HLA-DRB1*13 group-specific alleles in the production of Rh and Kell alloantibodies.Materials and Methods106 TDT patients were recruited for this study (54 responders and 52 non-responders). Responder patients developed Rh, Kell and/or specificities alloantibodies. HLA genotyping was done with Sequence-Specific Primers (SSP-PCR) and the results were compared between two groups.ResultsA significant association was found between anti-K (P=0.021, OR=2.546, 95%CI) and anti-E (P=0.049, OR=2.304, 95%CI) alloantibodies production with DRB1*11, respectively. Development of Anti-K and Anti-E alloantibodies were associated with DRB1*11 (P = 0.021, OR = 2.546, 95%CI) (P = 0.049, OR = 2.304, 95%CI), respectively. Further analysis showed that DRB1*11 is more frequent in multi responders (responder with both Rh and Kell alloantibodies) than mono-responders, 71% Versus 29%. There was not found any association between the DRB1*13 group-specific allele and the production of alloantibodies (P = 0.584, OR = 0.308, 95%CI).ConclusionsThe evidence from this study suggests that detecting the DRB1*11 group-specific allele before starting transfusion can be useful to identify susceptible patients, increase HSCT transplantation compatibility and blood transfusion management.     

Genotyping of blood groups in alloimmunized patients with β-thalassemia major by T-ARMS-PCR and multiplex-aso-pcr

IntroductionBeta-thalassemia major is a severe hemolytic anemia requiring life-long blood transfusion. Planned random donor blood transfusion is associated with alloimmunization against incompatible antigens. Determination of the minor blood group systems phenotype or genotype, and administration of the compatible blood components can significantly reduce the rate of alloimmunization.The present study aimed to determine the prevalence of alloimmunization, and genotype/phenotype characteristics of the minor blood groups systems in patients with β-thalassemia major.Material and methodsThis study was conducted on 1147 β-thalassemia major patients. Initially, antibody screening and antibody identification were performed. Then, phenotyping and genotyping for the Rh, Kell, Kidd, and Duffy blood groups were done in alloimmunized patients using monoclonal antibodies and Multiplex-Allele Specific Oligonucleotide-Polymerase Chain Reaction (Multiplex-ASO-PCR) and Tetra-primer amplification refractory mutation system–PCR (T-ARMS-PCR), respectively. Any phenotype/genotype discrepancy was assessed by direct sequencing.ResultsNinety-seven (8.5 %) out of 1147 patients had alloantibodies against the minor blood group antigens (44 males, 45.4 %, and 53 female, 54.6 %). The most common alloantibodies were against the RH (n: 47, 48.5 %), and the Kell (n: 23, 23.7 %) blood groups systems. Twenty-three (2.1 %) genotype/phenotype discrepancies out of 1067 tests, including 9 in the Rh (9.3 %), 8 in Duffy (34.8 %), and 6 in Kidd (26.1 %) blood groups were detected. No discrepancy was found in the Kell blood group system. Direct sequencing revealed that the results of molecular methods were correct.ConclusionMultiplex-ASO-PCR and T-ARMS-PCR molecular methods are fast, reliable and cost-benefit molecular methods for the minor blood group genotyping in multi-transfused β-thalassemia major patients.     

Autoantibody formation after alloimmunization: are blood tranfusions a risk factor for autoimmune hemolytic anemia?

BACKGROUND: The development of RBC autoantibodies resulting from or associated with allogeneic blood transfusions (i.e., RBC autoimmunization) is not a well-recognized complication of RBC transfusions. STUDY DESIGN AND METHODS: T: he presentation, laboratory evaluation, clinical course, and management of two patients whose autoimmune hemolytic anemia followed allogeneic blood transfusion and occurred in association with the development of one or more alloantibodies is described. A retrospective analysis was performed of our blood-bank records over 1 year to determine the frequency of RBC autoimmunization associated with alloimmunization. RESULTS: Out of 2618 patients who had a positive DAT or IAT, 121 were identified with RBC autoantibodies; 41 of these patients had both allo- and autoantibodies to RBC antigens, whereas the remainder, 80, had only autoantibodies. At least 34 percent (12/41) of these patients (none with hemoglobinopathy) developed their autoantibodies in temporal association with alloimmunization after recent blood transfusion(s). CONCLUSION: RBC autoimmunization and the development of autoimmune hemolytic anemia should be recognized as a complication of allogeneic blood transfusion. The need for additional blood transfusion was successfully avoided in one patient by treatment with recombinant human EPO and corticosteroid therapy. Once RBC autoimmunization is identified, subsequent management should incorporate a strategy that minimizes subsequent exposure to allogeneic blood.     

Frequency and specificity of Red blood cell alloantibodies in multitransfused Egyptian patients with hematological and nonhematological malignancies

BackgroundRepeated blood transfusions can result in the production of alloantibodies against one or more red blood cell (RBC) antigens, which can complicate future transfusions.AimThis study aims to determine the frequency and specificities of RBC alloantibodies in multitransfused adult cancer patients admitted at the National Cancer Institute, Cairo University.MethodsThis cohort study enrolled 2000 multitransfused cancer patients diagnosed with different types of malignancies; they were screened for RBC alloantibodies using Serascan Diana 3 and Identisera Diana 11-cell identification panels (Diagnostic Grifols, Spain).ResultsOf the 2000 patients tested, 25 had autoantibodies and were excluded from the study. Of the remaining 1975 patients, 181 patients had a total of 267 different alloantibodies (9.16%), with some having more than 1 antibody detected. Our study showed that more female patients (63%) than male patients (37%) had acquired RBC alloantibodies, and a higher prevalence of alloantibodies in patients with nonhematological malignancies (14%) compared with those with hematological malignancies (6.5%). The highest percentage of alloantibodies belongs to the Rh blood group system, followed by the Kell system, then Duffy, MNS, Kidd, and Lewis. Patients who received combined chemotherapy and immunotherapy exhibited a lesser antibody response compared to other patients.ConclusionThe prevalence of alloimmunization in our study is comparable to previous reports on oncology patients. Repeated blood transfusions, which can lead to alloimmunization, often complicate future transfusions. Therefore, we recommend extending phenotype matching for patients who are presumed to depend on blood transfusions in the long term.     

Red cell alloantibodies in thalassemia major. Results of an Italian cooperative study

Clinical and serological data on 1435 Italian thalassemia major patients were collected during a cooperative study involving 19 centers in 10 regions. The main findings were as follows: 18 percent of the patients were under 6 years of age, 63 percent between 6 and 15, and 19 percent over 15. Forty-one percent had undergone splenectomy. Sixty-two percent of the patients were maintained at pretransfusion hemoglobin levels higher than 10 g per dl, 36 percent between 8 and 10 g per dl, and 2 percent below 8 g per dl. Overall, 5.2 percent of the patients had clinically significant red cell alloantibodies (136 alloantibodies in 74 patients). One-half of the immunized patients had more than one and one-fourth had more than two alloantibodies. The specificities of the 136 alloantibodies were almost exclusively confined to the common antigens of the Rh, Kell, Kidd, and Duffy systems, in that decreasing order of frequency. The antibody screening procedure, using a low-ionic-strength solution antiglobulin test against a three-red-cell panel and the patient's own red cells (autocontrol) with a serum to cell ratio of 100 to 1 was shown to be an adequate technique for red cell antibody detection.     

电子配血技术对减少输血患者Rh血型系统同种抗体产生的意义

目的 探讨电子配血技术应用对减少受血者Rh血型同种抗体产生的意义.方法 将本院2018年1月1日-2020年3月31日期间住院且仅输注去白悬浮红细胞的Rh(D)阳性的患者(22 528人,将电子配血符合优先级Ⅰ级、Ⅱ级的患者21 334人设为对照组,将符合优先Ⅲ级的患者共1 194人设为试验组,对用血者和献血者进行AB...     

Prospective RBC phenotype matching in a stroke-prevention trial in sickle cell anemia: a multicenter transfusion trial

BACKGROUND: Most sickle cell anemia patients undergo transfusion therapy to prevent complications. The Stroke Prevention Trial in Sickle Cell Anemia showed that transfusion therapy is effective in the primary prevention of stroke. Despite its efficacy, transfusion therapy is limited by alloimmunization. The purpose of this study was to determine if a multicenter trial could implement a transfusion program utilizing phenotypically matched blood to reduce alloimmunization. STUDY DESIGN AND METHODS: One hundred thirty children underwent RBC phenotyping and antibody screening with review of blood bank records. The protocol required use of WBC-reduced RBCs, which were matched for E, C, and Kell. Monthly alloantibody testing and review of transfusion forms were performed to determine compliance and the occurrence of any adverse events. RESULTS: Patient RBCs expressed a low frequency of Kell (2%), E (20%), and C (25%) antigens. Sixty-one patients received 1830 units. Ninety-seven percent of all units were WBC reduced. Only 29 units were inadvertently not matched for E, C, and Kell. Five patients (8%) developed a clinically significant alloantibody. Four developed a single antibody to E or Kell. Three patients (5%) developed a warm autoantibody. There were 11 transfusion reactions and 8 transfusion-associated events. Transfusion reactions included 6 febrile reactions (0.33%/unit), 3 allergic (0.16%/unit), and 2 hemolytic (0.11%/unit). Associated events included 4 episodes of hypertension (0.22%/unit), 3 crises (0.16%/unit), and 1 transient ischemic attack (0.05%/unit). CONCLUSION: This is the first multicenter study to show that extended RBC phenotyping can be implemented nationwide. Compared to studies, the alloimmunization rate dropped from 3 percent to 0.5 percent per unit, and hemolytic transfusion reactions dropped by 90 percent. It is recommended that all transfused sickle cell anemia patients be antigen matched for E, C, and Kell. Patients should be closely monitored during transfusions to avoid preventable risks.     

Red cell alloimmunization in multitransfused HLA-typed patients

The authors studied retrospectively the formation of clinically significant red cell (RBC) alloantibodies in 958 HLA-typed, multiply transfused patients receiving kidney (603 patients) or liver (263 patients) transplants or plateletpheresis transfusions (92 patients). RBC alloantibodies were found in 91 (9.5%) of these patients and multiple antibodies in 35 (3.7%). Rh (D, C, c, and E) antibodies accounted for 49 percent of the total and Kell antibodies for 31 percent. Antibodies were found in 15 percent of apheresis recipients and in 8.6 percent of renal and 9.5 percent of liver transplantation patients. No association was found between any HLA-A, HLA-B, or HLA-DR phenotype and the presence of RBC alloantibodies, either in general or when analyzed according to the specific antibody. Renal transplant patients with RBC alloantibodies were somewhat more broadly HLA-alloimmunized than were those without RBC alloantibodies. Patient gender did not affect these results. The authors concluded that the immune response to RBC alloantigens is independent of HLA type but is associated with an increased level of HLA antibody formation.     

Platelet transfusion in an infant leading to formation of anti-D: implications for immunoprophylaxis

BACKGROUND: The immature infant immune system rarely makes RBC alloantibodies; however, most studies confirming the absence of alloantibodies in infants have involved transfusions that were matched for one of the most immunogenic antigens, rhesus D. The potential for D- infants to develop anti-D is unknown. Specifically, this issue has not been analyzed for infants receiving whole-blood-derived PLTs from D+ donors. The importance of understanding such risk is underscored by the fact that anti-D formation can be prevented by the administration of Rh immunoglobulin. CASE REPORT: A D- infant with congenital heart disease received two D-mismatched whole-blood-derived PLT units at 17 weeks of age. He did not receive Rh immunoglobulin prophylaxis. Upon a subsequent admission 13 months later, anti-D was identified in his plasma sample. CONCLUSION: The case presented here demonstrates that a young infant can respond to less than 0.6 mL of D+ RBCs and documents the youngest patient to have developed a RBC alloantibody from a PLT transfusion. To prevent anti-D formation, we recommend administering Rh immunoglobulin to all D- pediatric patients that receive PLT transfusions from D+ donors [correction].     

Hemolytic Disease of the Fetus and Newborn: Modern Practice and Future Investigations

Red blood cell (RBC) sensitization occurs in some women in response to exposure to paternally derived RBC antigens during pregnancy or to nonself antigens on transfused RBCs during their lifetime. Once sensitized, future pregnancies may be at risk for hemolytic disease of the fetus and newborn. Although great strides have been made over the past few decades in terms of identifying blood group antigens and in predicting fetal anemia through the use of noninvasive monitoring, many questions remain in terms of understanding RBC alloimmunization risk factors, preventative therapies, and treatment strategies. At the present time, there is room for improvement in these areas in both developed and developing countries. Evidence-based, universal guidelines describing recommended RBC antigen matching transfusion strategies for girls or women, before pregnancy or during intrauterine transfusions, would be welcomed. A better understanding of the mechanism(s) of action of Rh immunoglobulin, first introduced more than half of a century ago and one of the most successful immunoprophylaxis therapies in existence today, would also be a large step forward. For example, answers to questions of the role(s) that fetal RBC clearance, antigen masking, antigen modulation, and immune suppression play in the effectiveness of Rh immunoglobulin may help to guide the development of novel preventative therapies during pregnancy for immunization to RhD and non-RhD antigens. Furthermore, a better understanding of the importance of anti-RhD or other alloantibody glycosylation patterns may be beneficial not only in developing such novel immunoprophylaxis therapies but also in predicting the clinical significance of existing maternal alloantibodies. One other area of need includes the development of therapies beyond intrauterine transfusions to mitigate the dangers of maternal alloantibodies to developing fetuses. We challenge physicians, scientists, and funding agencies to prioritize studies of RBC alloimmunization and hemolytic disease of the fetus and newborn and to invest in the children of our future.     

Extended red blood cell antigen matching for transfusions in sickle cell disease: a review of a 14-year experience from a single center (CME)

BACKGROUND: Alloimmunization to red blood cell (RBC) blood group antigens is a major complication for patients with sickle cell disease (SCD), which limits the usefulness of RBC transfusion. Here, we report our experiences with extended RBC antigen matching for SCD patients. STUDY DESIGN AND METHODS: Records for 99 SCD patients transfused only with the extended matching protocol between 1993 and 2006 were reviewed. Patients and donors were phenotyped for 20 blood group antigens and RBC units that were negative for antigens not expressed by the recipient were provided. When necessary, mismatches were allowed at Le^a, Le^b, Fy^b, and MNSs to meet requirements for antigens regarded as the most clinically significant. Matched RBC units (6946) were provided to 99 patients (mean, 70 units/patient; range, 1‐519 units/patient). Eliminating mismatches, 90% of the transfusions matched all other negative antigens. RESULTS: Seven alloantibodies were detected in seven patients resulting in 7% alloimmunized at a rate of 0.1 antibodies per 100 units transfused. Three recipients who developed antibodies were D mosaic and would have been mistyped with serologic techniques. Alloimmunization was decreased compared to ABO and/or D matching at our institution and others. Twelve autoantibodies and no severe hemolytic transfusion reactions were reported. CONCLUSION: Exact matching for ABO, Rhesus, Kell, Kidd, and Fy^a and extending this match whenever possible is an effective strategy to reduce alloimmunization to RBC antigens. Consideration should be given to exploring this conclusion further with a controlled, multi‐institutional trial to determine efficacy, cost‐benefit analysis, and reproducibility of this approach.     

Coexistence of autoantibodies and alloantibodies to red blood cells due to blood transfusion

BACKGROUND: Autoantibodies (AUTO) to red blood cells (RBCs) are frequently associated with alloantibodies (ALLO). The mechanism for the coexistence of these antibodies is obscure. STUDY DESIGN AND METHODS: Between August 1998 and June 2006, all in- and outpatients of the Charité University Hospital, Berlin, with detectable AUTO were included in this study. Serologic examination was performed with standard techniques for the detection of RBC antibodies. RESULTS: A total of 717 patients were found to have AUTO, with ALLO observed in 200 of these patients (28%). The history of antibody production could be evaluated in 98 of the 200 patients. Both AUTO and ALLO were due to RBC transfusion in 73 cases (75%) and peripheral blood progenitor cell transplantation in 6 cases (6%). Nine (9%) patients were primarily alloimmunized and subsequently developed AUTO. The remaining 10 (10%) patients were primarily autoimmunized and later developed ALLO. Only 6 of these patients had chronic idiopathic autoimmune hemolytic anemia. CONCLUSION: The majority of AUTO associated with ALLO appears to be due to RBC transfusion that must be recognized as a major cause for autoimmunization.     

Induction of additional red cell alloantibodies after intrauterine transfusions

BACKGROUND: The aim of this study was to determine the frequency and origin of additional alloantibodies directed against red cells (RBCs) after intrauterine transfusion (IUT). STUDY DESIGN AND METHODS: Between March 1987 and December 1992, fetuses with severe hemolytic disease (n = 91) received a total of 280 ultrasound-guided IUTs of RBCs from unrelated donors. The specificity of alloantibodies to RBCs in maternal serum was determined both before and after each IUT. If additional alloantibodies directed against RBCs were detected, their origin was determined by phenotyping the fetal, donor, and paternal RBCs for each particular antigen. The study included a control group of 69 pregnant women who underwent either amniocentesis or fetal blood sampling. RESULTS: Production of additional alloantibodies directed against RBC antigens was detected in 24 women (26%). The source of the immunizing antigen, either donor or fetus, was identified in 14 patients. The additional alloantibodies were directed against fetal antigens in 11 women and against donor antigens in 3. One additional alloantibody directed against donor antigen clearly reduced the survival of donor RBCs. The fetus and the donor shared the immunizing antigen in four cases, and in one case, the antibody occurred naturally. In five cases, the source of the immunizing antigen was not determined. In the control group, additional antibodies were detected in two patients. CONCLUSION: IUT therapy is associated with a high incidence of additional alloantibodies. In the majority of patients, the use of maternal RBCs for IUT would not have prevented additional formation of alloantibody to RBCs.     

Benefits of blood group genotyping in multi‐transfused patients from the south of Brazil

We evaluated the usefulness of blood group genotyping as a supplement to hemagglutination to determine the red blood cell (RBC) antigen profile of polytransfused patients with hematological diseases and renal failure. Seventy‐nine patients were selected. They all received more than three units of blood and eight (10%) had already clinical significant alloantibodies occurring alone or in combination against Rh, K, Fya, and Di antigens. DNA was prepared from blood samples and RHCE*E/e, KEL*01/KEL*02, FY*01/FY*02 and JK*01/JK*02 alleles were determined by using PCR‐RFLP. RHD*/RHD*Ψ and RHCE*C/c were tested using multiplex PCR. Discrepancies for Rh, Kell, Duffy, and Kidd systems were found between the phenotype and genotype‐derived phenotype in 16 of the 38 chronically transfused patients. The genotypes of these patients were confirmed by DNA array analysis (HEA Beadchip^?; Bioarray Solutions, Warren, NJ). Genotyping was very important for the determination of the true blood groups of the polytransfused patients, helped in the identification of suspected alloantibodies and in the selection of antigen‐negative RBCs for transfusion. J. Clin. Lab. Anal. 24:311–316, 2010. © 2010 Wiley‐Liss, Inc.