The Impact of Extended Typing On Red Blood Cell Alloimmunization in Transfused Patients

Maternal red blood cell alloimmunization prevalence in the United States

ABSTRACT

Hemolytic disease of fetus and newborn (HDFN) is a life-threatening disease mediated by maternal alloimmunization to red blood cell (RBC) antigens. Studies of maternal alloimmunization prevalence in the United States lack national data. This study describes prevalence and trends in alloimmunization in pregnancy in the United States. RBC antibodies (abs) were identified in a large, nationwide, commercial laboratory database from 2010 through 2021. The cohort comprised pregnancies for which the year of laboratory collection and patient's state of residence were available. Data were normalized based on US Centers for Disease Control and Prevention estimates of live births and weighted by year and US Census Division. Cochrane-Armitage tests assessed temporal trends of alloimmunization. Of 9 876 196 pregnancies, 147 262 (1.5%) screened positive for RBC abs, corresponding to an estimated prevalence of 1518 of 100 000 pregnancies. Of identified RBC abs, anti-D comprised 64.1% pregnancies (586/100 000). Prevalence of other high-risk RBC abs for HDFN included anti-K (68/100 000) and anti-c (29/100 000). Incidence of all 3 high-risk abs increased from 2010 to 2021 (all P < .001). Among almost 10 million pregnancies in the United States, comprising an estimated 14.4% of all pregnancies, 1.5% screened positive for RBC abs. Almost three-quarters (679/100 000 [74.3%]) of RBC abs identified were high risk for HDFN. Although prevalence of anti-D is difficult to interpret without the ability to distinguish alloimmunization from passive immunity, it remains problematic in HDFN, ranking second only to anti-K in critical titers. Given the sequelae of HDFN, new initiatives are required to reduce the incidence of alloimmunization in patients of reproductive potential.

Standard Compared With Extended Red Blood Cell Antigen Matching for Prevention of Subsequent Hemolytic Disease of the Fetus and Newborn: A Systematic Review

OBJECTIVE

To systematically review and meta-analyze alloimmunization among recipients of red blood cells (RBCs) matched for ABO blood type and Rhesus D (ABO+D) antigen compared with those also matched for c, E, and Kell (cEK).

DATA SOURCES

Four online databases (Medline, Scopus, EMBASE, ClinicalTrials.gov) were searched from March 28, 2023, to April 1, 2024. The search protocol was peer reviewed and published on PROSPERO (CRD42023411620).

METHODS OF STUDY SELECTION

Studies reporting alloimmunization as the primary outcome among recipients of RBCs matched for ABO+D or additional cEK matching were included. Patients transfused with unmatched RBCs or a mixture of matching regimens were excluded. Risk of bias was assessed with Cochrane Tool to Assess Risk of Bias in Cohort Studies and Tool for Risk of Bias. Random-effects meta-analysis was used to combine effect estimates.

TABULATION, INTEGRATION, AND RESULTS

Ten studies met criteria. Risk of bias was low. Overall, 91,221 patients were transfused, of whom 40,220 (44.1%) received additional cEK-matched RBCs. The overall rate of alloimmunization was 6.2% (95% CI, 2.5-14.9%) for ABO+D-only matching and 1.9% (95% CI, 0.7-5.1%) when cEK was added. Time of follow-up antibody testing ranged from 6 to 18 months after transfusion. Additional cEK match was associated with significantly less alloimmunization compared with standard ABO+D match (odds ratio [OR] 0.37, 95% CI, 0.20-0.69). This association remained when chronically transfused patients were excluded (OR 0.65, 95% CI, 0.54-0.79) and for alloimmunization to c, E, or K antigens only (OR 0.29, 95% CI, 0.18-0.47).

CONCLUSION

Additional cEK RBC matching protocols were associated with lower odds of recipient alloimmunization. Given severe sequelae of alloimmunization in pregnancy, routine cEK matching for transfusion in people with pregnancy potential younger than age 50 years in the United States merits consideration.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42023411620.

Haemolytic transfusion reactions caused by non-ABO red cell antibodies reported to the Norwegian Haemovigilance System 2004-2020

BACKGROUND AND OBJECTIVES

The aim of this study was to analyse the reports received in the Norwegian Haemovigilance System from 2004 to 2020 on acute and delayed haemolytic transfusion reactions caused by non-ABO red cell antibodies.

MATERIALS AND METHODS

Antibody specificity, clinical symptoms and outcomes were included when available.

RESULTS

After transfusion of 3.7 million red cell concentrates, reports on 78 cases of haemolytic transfusion reactions caused by non-ABO red cell antibodies were received, corresponding to an incidence of 1 in 47,000 transfused red cell concentrates. There were 30 acute and 48 delayed haemolytic transfusion reactions. A total of 113 red cell antibodies were found: 82 alloantibodies, 6 autoantibodies and 25 cases where the antibody specificity could not be determined. Two fatalities occurred: one caused by anti-Wra and one caused by an unidentified red cell antibody. The most frequently reported antibody specificities were those in the Rh and Kidd blood group systems, representing 24% and 14%, respectively, of all the antibodies identified. In six cases, errors occurred, leading to the issuing of blood units without the required phenotype match.

CONCLUSIONS

Despite the possible underreporting, the low number of serious haemolytic transfusion reactions reflects an adequate pre-transfusion practice by the Norwegian blood banks.

Timing matters: An analysis of the relationship between red cell transfusion timing and hospitalization outcomes in sickle cell crisis patients using the National Inpatient Sample database

Vaso-occlusive pain crisis is a debilitating complication of sickle cell disease (SCD) and it is the most common cause of hospitalization among these individuals. We studied the inpatient outcomes among patients admitted with sickle cell crisis based on the timing of red blood cell transfusion. In this retrospective study, we used the United States National Inpatient Sample (NIS) data for the year 2019, to identify adult patients hospitalized with the principal diagnosis of sickle cell crisis who received simple red blood cell transfusion during their hospitalization. Patients were divided into two groups. Those who received simple red cell transfusion within 24 hours of admission were classified as early transfusion. After adjusting for confounders, the mean adjusted length of stay for patients with early transfusion was significantly lower than those who received a late blood transfusion by 3.51 days (p-value < 0.001) along with a decrease in mean adjusted hospitalization charges and cost, by 25,487 and 4,505 United States Dollar (USD) respectively. The early red cell transfusion was also associated with a decrease in inpatient mortality, demonstrated by an adjusted odds ratio (aOR) of 0.19 (p-value 0.036), and a reduction in in-hospital sepsis, with an aOR of 0.28 (p-value < 0.001), however, no statistically significant difference was found between the two groups regarding acute respiratory failure requiring intubation, vasopressors requirement, acute kidney injury requiring dialysis and intensive care unit (ICU) admission. We recommend timely triage and reassessment to identify sickle cell crisis patients requiring blood transfusion. This intervention can notably affect the inpatient length of stay, resource utilization, and hospitalization outcomes.

Frequency of Extended Red Cell Antigen Phenotype Among Patients of Hematological Diseases: A Single Center Study

Background

Alloimmunization of erythrocytes is a major problem in patients with hematological diseases that require frequent blood transfusions. Matching of extended red cell antigens of Kell, MNS, Kidd, and Duffy can decrease the risk of alloimmunization. Hence, in this study, the frequencies of the extended red cell phenotypes were explored.

Objective

To find out the frequency of extended red blood cell antigen phenotypes among patients with hematological diseases.

Methods

This cross-sectional research study was performed on 488 patients diagnosed with hematological diseases who required blood transfusion at the National Institute of Blood Disease and Bone Marrow Transplantation Karachi for a period of 1.42 years from November 2019 to March 2021. The blood of patients was analyzed for antigen phenotypes of different blood group systems including Kell, MNS, Kidd, and Duffy. The data obtained were interpreted.

Results

Among the 488 patients, 284 (58.20%) patients were male, and 204 (41.80%) patients were female with a mean age of 8.1 years. Beta thalassemia was the most common hematological disease reported in 354 (72.5%) of the patients. The most common blood group was O positive reported in 182 (37.3%) of the patients followed by B positive blood group in 124 (25.4%). The frequencies of extended red cell antigen phenotypes in the patients were K antigen 14 (2.9%), Kp^a antigen 26 (5.3%), Kp^b antigen 424 (86.9%), Fy^a antigen 360 (73.8%), Fy^b antigen 260 (53.3%), Jk^a antigen 294 (60.2%), Jk^b antigen 326 (66.8%), M antigen 410 (84.0%) and N antigen 306 (62.7%).

Conclusion

Beta thalassemia was the most common hematological disease followed by iron deficiency anemia, aplastic anemia, and acute leukemia. Patients with hematological diseases had a higher prevalence of Kp^b antigen followed by M, Fy^a, Jk^b, N, Jk^a, Fy^b, Kp^a, and K antigen. O positive was the most frequent blood group followed by B positive, A positive and AB positive blood group.

Rare Blood Groups in ABO, Rh, Kell Systems - Biological and Clinical Significance

Background: The frequency of ABO, Rh and Kell blood group antigens differs among populations of different ethnic ancestry. There are low-frequency antigens (<1%) and high-frequency antigens (>90%). A rare blood group is defined as the absence of a high-frequency antigen in the general population, as well as absence of multiple frequent antigens within a single or multiple blood group systems. Aim: To perform red blood cell typing and to calculate the antigen and phenotype frequencies, in order to identify rare blood group donors within the clinically most important АВО, Rh and Kell systems. Material and Methods: АВО, Rh (D, C, E, c, e) and Kell (K) antigen typing was performed using specific monoclonal sera and microplate technique, while Cellano (k) typing was performed with a monoclonal anti-k, antihuman globulin and column agglutination technique. Weak ABO subgroups were determined using the absorption elution method or molecular genotyping (PCR-SSP). Results: ABO antigen frequency is: A (40.89%), O (34.22%), B (16.97%), AB (7.92%) and weak ABO subgroups (0, 009 %). The established genotypes were AxO1 (0, 0026%) and AxB (0, 001%). Rh antigen frequency is: D (85.79%), C (71.7%), c (76.0%), E (26.0%) and е (97.95%). The most common Rh pheno-type is the DCcee (32.7%) while the rarest phenotype is the DCCEE phenotype (0. 003%). The prevalence of K and k antigen is 7.5% and 99.94%, respectively. The frequency of the rare phenotype K+k- is 0.06%. Conclusion: Large scale phenotyping of blood group antigens enables the identification of blood donors with rare blood groups for patients with rare phenotypes or with antibodies to high-frequency antigens and to frequent antigens within one or more blood group systems.

Genotyping versus phenotyping of non-ABO erythrocyte antigens in patients with the Mediterranean hemopathic syndromes: Effect of transfusion therapy

The Mediterranean hemopathic syndromes (MHS) are the most prevalent hemoglobinopathies in the Mediterranean basin. Transfusion therapy is the main therapy for these disorders, particularly for severe forms of the disease. Currently, pre-transfusion serological typing of erythrocyte antigens is the standard tool for reducing complications of transfusion in those patients. This study compared genotyping with phenotyping of non-ABO erythrocyte antigens in patients with MHS and assessed the effect of transfusion therapy on their results. One-hundred ninety-eight MHS patients were recruited, screened, and proven negative for allo-antibodies. They were grouped into two groups: (1) 20 newly diagnosed patients with no transfusion history and (2) 178 previously diagnosed patients undergoing transfusion therapy. Patients were interviewed and clinically examined. Full blood count (FBC) and high performance liquid chromatography (HPLC) were done for group 1 only. Genotyping and phenotyping of non-ABO erythrocyte antigens were performed for group 1, and 25 patients out of group 2 were propensity score-matched (PSM) with group 1. Both groups were gender and age matched; 55% and 74% of groups 1 and 2 had major disease, respectively. Insignificant differences were observed between genotyping and phenotyping of non-ABO erythrocyte antigens in group 1, while significant discrepancies and mixed field results were noted in group 2 patients. Discrepancies were obvious with JKa, JKb, and little c antigens. Conclusively, molecular typing is a powerful tool for pre-transfusion testing in chronically transfused MHS patients. This testing reduces incidence of transfusion reactions. JKa, JKb and little c antigens are the most clinically significant non-ABO erythrocyte antigens.

Clinical outcome of transfusions with extended red blood cell matching in β-thalassemia patients: A single-center experience

BACKGROUND

The development of alloantibodies may complicate the management of patients with β-thalassemia. An extended antigenic matching may reduce the risk of alloimmunization. Our previous study showed that the introduction of molecular red blood cell (RBC) typing allows finding suitable blood units for multi-transfused patients. The aim of this study was to evaluate the benefit of RBC transfusion with extended antigenic match.

MATERIALS AND METHODS

At the University of Campania "L. Vanvitelli", we selected β-thalassemia major patients (age ≤23 years), without preformed alloantibodies. Data of patients receiving transfusion of leukoreduced RBC units for a period of one year with partial better match (PBM) including ABO, RhD, C/c, E/e, K/k antigens and consecutive one year with extended match (EM) including ABO, RhD, C/c, E/e, K/k, Fy^a/Fy^b, Jk^a/Jk^b, M/N, S/s antigens, were compared.

RESULTS

Eighteen patients, 8 males and 10 females with a mean age of 15.4 years (6.4 SD) received a mean number of 41.2 (6.0 SD) RBC units transfused with PBM and 41.8 (6.2 SD) with EM protocols. After two years of RBC transfusions with both antigen matching protocols, no new alloantibodies were developed in patients. No significant differences in Hb concentration and volume of RBC transfused were found between PBM and EM protocols.

CONCLUSIONS

Thalassemia patients may benefit from receiving RBC transfusions based on extended antigen matching as demonstrated by the lack of new alloantibodies. However, our data show a high concordance between PBM and EM protocols considering pre-transfusion Hb, increment of Hb and volume of RBC transfused.

The erythrocyte alloimmunisation in patients with sickle cell anaemia: a systematic review

Transfusion therapy is a common practice in the treatment of anaemia and can cause erythrocyte alloimmunisation. To systematise data related to erythrocyte alloimmunisation in patients with sickle cell disease (SCD), a bibliographic search was carried out in September 2017 to search for studies in four electronic databases. (i) Referring to the original work, (ii) being cohort or case-control, (iii) having been developed with individuals with SCD and (iv) having evaluated the erythrocyte alloimmunisation. Two reviewers identified the articles for inclusion in the study, extracted the predetermined data and carried out the evaluation of the methodological quality of the work. 21 studies were selected; the studies included data on 20 636 individuals (children and adults), were mostly published in the last 10 years, were developed in the United States and had high methodological quality. The occurrence of erythrocyte alloimmunisation ranged from 4·4 to 76%, and there was a higher rate of alloimmunisation against antigens of the Rh system. The risk factors for alloimmunisation were age; gender (female); red blood cell (RBC) units received; presence of ≥1 autoantibodies, TNF-α, interleukin (IL1B), human leukocyte antigens (HLA)-DRB1 gene polymorphisms; first blood transfusion (BT) after 5 years of age, transfusion episodic, multiple or during inflammatory events, acute chest syndrome (ACS) and vase-occlusive crisis (VOC); increased percentage of CD41 T memory cells; and positive direct antiglobulin test. Transfusion policies should be developed to protect the patient and his or her health based on the main factors associated with its incidence.