Red blood cell alloimmunization among hospitalized patients: transfusion reactions and low alloantibody identification rate

Phenotypic Identification of Blood Groups in Blood Donors: A Peruvian Multicenter Analysis

Background

Red blood cell alloimmunization currently continues to be a significant problem during the blood transfusion process, where phenotypic identification plays a clinically relevant role in its prevention. The objective of the study was to carry out the phenotypic identification of blood groups in blood donors from three hospitals in Lima.

Methods

A cross-sectional study was conducted, including 20,141 blood donors in three hospitals in Lima, Perú during the period from January to June 2023. Red blood cell phenotyping was performed by the gel agglutination method using gel cards with the IH-500 automated system.

Results

A predominance of donors within the age group of 29 to 38 years (30.9%) was observed, with the majority being men (69.5%). Most donors were Peruvian (97.9%), and among foreign donors (2.1%), Venezuelans predominated (1.5%). In the distribution of the ABO and RhD blood groups, the O Rh+ phenotype predominated in 79% of the donors. In the phenotypic distribution of the Rh system, the presence of the D antigen was observed in 98.1% of the donors, with the c phenotype being the most frequent (76.4%). For the Kidd system, 70.7% of the donors presented the Jka antigen and 81.9% the Jkb antigen. In the Duffy system, 77.7% of the donors presented the Fya antigen and 50% the Fyb antigen. For the MNS system, 93.7% of donors had the S antigen and 76.1% had the s antigen. It was also found that 1.5% of donors are carriers of the Kell antigen, all of which are clinically important.

Conclusion

The phenotypic identification of blood groups in blood donors from three hospitals in Lima highlighted the clinical relevance of identifying less common antigens in the Kell, Kidd, Duffy, and MNS systems to prevent alloimmunization during blood transfusions.

Assessment of erythrocyte alloimmunization among patients treated at a Brazilian university hospital

INTRODUCTION

Alloimmunization and transfusion reactions underscore the crucial role of precise immunohematological techniques to enhance safety in transfusion. This study aims to determine the frequency of alloimmunization in patients treated at a Brazilian university hospital, investigate demographic, clinical, and epidemiological characteristics of patients with positive irregular antibody screening, as well as to assess the frequency of erythrocyte antigens and anti-erythrocyte antibodies in the population.

MATERIALS AND METHODS

This retrospective observational study included all irregular antibody-positive patients treated at the transfusion service of Hospital de Clínicas of the Federal University of Uberlandia between January 2019 and December 2020.

RESULTS

Of the 201 irregular antibody-positive patients, alloimmunization was more common in women (64.2%) than in men (35.8%). Blood groups A (39.8%) and O (38.8%), and Rh positive samples (69.1%) predominated, and about half (48.2%) of the patients were transfused for preoperative procedures. The most frequently found clinically significant alloantibodies were anti-D (27.2%), anti-E (15.0%), and anti-Kell (11.5%). Of the patients, 30.6% had multiple antibody associations, with anti-D and anti-C being the most common combination. Erythrocyte immunophenotyping was performed for 76 patients with the most frequent antigens detected being e (100%), c (86.8%), and C (40.8%). Among the 14 pregnant women evaluated, most were multiparous, 85.7% had anti-D as the most prevalent antibody, and had the A-negative blood type (33.3%).

CONCLUSION

Alloantibody screening and identification associated with erythrocyte immunophenotyping are necessary for a better understanding of the alloimmunized population, ensuring greater safety and efficacy of transfusion therapy in the hospital setting.

Red cell alloimmunization in multitransfused hepatobiliary patients at hospital Selayang

BACKGROUND

Transfusion support is vital for the management of patients with hepatobiliary disease. Repeated blood transfusions increase the risk of alloimmunization, i.e., the development of alloantibodies, which might lead to difficulties in blood crossmatching.

AIMS

This study aims to: (1) determine the incidence of red blood cell (RBC) alloimmunization and (2) evaluate the associations between antibody development and demographic factors among hepatobiliary patients.

METHOD

ABO blood grouping, antibody screening, antibody identification and crossmatch were done on all patients samples included in the study.

SETTINGS AND DESIGN

A cross-sectional study was conducted from February 2021 to September 2021, with a total of 132 samples from hepatobiliary patients. The relationships between RBC alloimmunization in transfused hepatobiliary patients and demographic factors (gender, age, and history of transfusion) were assessed by binary logistic regression.

RESULTS

Overall, 67.4% of the patients developed alloimmunization. The majority had a single alloantibody (75.2%) and the most frequently identified antibody specificities were anti-E (37.6%), anti-c (12.8%), anti-Mia (14.4%), and anti-Kidd (11.2%). The predominant antibodies were those against the Rh system (58.4%). Female patients recorded the highest incidence of alloimmunization (69.8%). Female patients also demonstrated a higher tendency to produce both anti-E + anti-c than male patients.

CONCLUSION

The prevalence of RBC alloimmunization is high among hepatobiliary patients and it may cause complications requiring multiple transfusions. The number of transfused packed cells has been clearly shown to be proportionally significant with the risk for alloimmunization in hepatobiliary patients. Hence, this study highlights the importance of immunohematology tests before blood transfusion.

Increased red blood cell alloimmunization rates in transfused aplastic anemia and myelofibrosis patients

BACKGROUND

Red blood cell (RBC) alloimmunization (AI) is a well-known complication of RBC transfusions, which results in the formation of alloantibodies to non-self antigens on donor RBCs, putting patients at risk of transfusion-related complications. The rate of AI with RBC transfusions in the general hospitalized population is estimated to be 2%-3%. However, some patients who are deemed "transfusion-dependent" require regular transfusions of blood products due to persistently low cell counts, putting them at even greater risk of RBC AI and increased morbidity. However, few studies currently exist investigating RBC AI in some transfusion-dependent patient populations, e.g., aplastic anemia (AA) and myelofibrosis (MF).

STUDY DESIGN AND METHODS

We conducted a 5-year retrospective review to investigate the prevalence of RBC AI, alloantibody incidence, and the number of RBC transfusions in AA and MF patients, who received RBC transfusions within our hospital system.

RESULTS

During the study period, 64 AA and 93 MF patients received 1301 and 2766 RBC transfusions, respectively. Compared to the RBC AI rate in the generalized hospitalized patient population (1%-2%), patients with AA and MF had an increased rate of RBC AI incidence rate at 14.1% and 12.9%, respectively. Furthermore, patients with primary MF demonstrated an isolated increased RBC AI incidence rate of 13.3%. The most common alloantibodies produced were anti-E and anti-K.

DISCUSSION

Within our institution, patients with AA and MF had increased incidence rates of RBC AI compared to the general hospitalized patient population and may benefit from an antigen-matched protocol to minimize AI-related complications.

Clinical consequences of a 30-day interval between antibody identifications

BACKGROUND

While studies have shown that antibody detection may be delayed if an antibody identification (ABID) is not performed every 3 days, little data exist on the potential major risk of an acute hemolytic transfusion reaction (aHTR).

STUDY DESIGN AND METHODS

At our institution, if no change in the screen, or a positive crossmatch, ABIDs are performed every 30 days. Between January 1, 2015 and May 31, 2019, all new antibodies detected within 28 days of a prior transfusion were identified. Testing results and patient charts were reviewed for evidence of hemolysis. The $211 patient charge was used to determine the cost for ABIDs performed during the studied time period.

RESULTS

For 36 patients, a new clinically significant alloantibody was detected within 28 days of an antigen-positive transfusion. Only one of these patients had a history of prior alloimmunization and put at possible risk due to the ABID policy. For this patient, while there was less than the expected increment to an antigen-positive unit, there was no clinical or laboratory evidence of an aHTR. During this same time, 6095 ABIDs were performed, at a cost of approximately $1.29 million, and 72,665 red cell transfusions occurred.

CONCLUSION

With an ABID every 30 days, only one patient, over 4.5 years, was put at potential risk for hemolysis from one transfusion (0.001% of the total units transfused during the time period). While antibody detection may be delayed, performing ABIDs every 30 days saves money and medical laboratory scientist time and should be balanced against potential patient harm.

Major and minor subgroup profile of blood in patients receiving multiple transfusions and donors

OBJECTIVE

It was aimed to profile the blood subgroups of our region and to reveal the prevalence of auto/alloimmune sensitization in patients who had to undergo multiple erythrocyte transfusions and to establish the sensitization profile by screening major and minor subgroups.

MATERIALS AND METHODS

In this study, the distribution of ABO and Rh system major subgroups was studied in 100 donor blood. As the patient group, 50 patients who received three or more red blood cell transfusions were included. In addition to this group, Kell, Lewis, Duffy blood group systems were studied.

RESULTS

According to the ABO system, 35% of the donors were in O, 33% in A, 17% in AB, and 15% in B. According to the Rh system, 75% is Dvi positive. Rh system is 99% e positive and 33% E positive in major subgroups and Kell1 positivity is 8%. In the patient group, 22% D(-) was determined compared to Rh blood group. Among the major subgroups of Rh, C was 68%, E was 14%, c was 76%, and e positivity was found to be 100%. The Kell1 negativity rate is 96%. The highest negativity was found in 86% Lea antigen in Lewis system, in 36% S antigen in MNS system, 34% Fyb antigen in Duffy system, and 24% Jka antigen in Kidd system. When inappropriate blood is given for any antigen, a double population is formed. The double negativities we detected in our study occurred as follows according to blood group systems: E 18%, C 12%, c 8%, Cw 2%, Kell 1 2%, M 8%, N 4%, S 18%, s 6%, Fya 8%, Jka 6%, Jkb 22%. Indirect Agglutination Test (IAT) was negative in all patients.

CONCLUSION

IAT negativity in all patient groups suggests that we do not develop alloimmunization, but the high rates of double population suggest a high risk of alloimmunization.

Rebuilding the hematopoietic stem cell niche: Recent developments and future prospects

Hematopoietic stem cells (HSCs) have proven their clinical relevance in stem cell transplantation to cure patients with hematological disorders. Key to their regenerative potential is their natural microenvironment - their niche - in the bone marrow (BM). Developments in the field of biomaterials enable the recreation of such environments with increasing preciseness in the laboratory. Such artificial niches help to gain a fundamental understanding of the biophysical and biochemical processes underlying the interaction of HSCs with the materials in their environment and the disturbance of this interplay during diseases affecting the BM. Artificial niches also have the potential to multiply HSCs in vitro, to enable the targeted differentiation of HSCs into mature blood cells or to serve as drug-testing platforms. In this review, we will introduce the importance of artificial niches followed by the biology and biophysics of the natural archetype. We will outline how 2D biomaterials can be used to dissect the complexity of the natural niche into individual parameters for fundamental research and how 3D systems evolved from them. We will present commonly used biomaterials for HSC research and their applications. Finally, we will highlight two areas in the field of HSC research, which just started to unlock the possibilities provided by novel biomaterials, in vitro blood production and studying the pathophysiology of the niche in vitro. With these contents, the review aims to give a broad overview of the different biomaterials applied for HSC research and to discuss their potentials, challenges and future directions in the field. STATEMENT OF SIGNIFICANCE: Hematopoietic stem cells (HSCs) are multipotent cells responsible for maintaining the turnover of all blood cells. They are routinely applied to treat patients with hematological diseases. This high clinical relevance explains the necessity of multiplication or differentiation of HSCs in the laboratory, which is hampered by the missing natural microenvironment - the so called niche. Biomaterials offer the possibility to mimic the niche and thus overcome this hurdle. The review introduces the HSC niche in the bone marrow and discusses the utility of biomaterials in creating artificial niches. It outlines how 2D systems evolved into sophisticated 3D platforms, which opened the gateway to applications such as, expansion of clinically relevant HSCs, in vitro blood production, studying niche pathologies and drug testing.

Rapidly freeze-dried human red blood cells for pre-transfusion alloantibody testing reagents

Prior to transfusion of red blood cells (RBCs), recipients must be tested for the presence of alloantibodies to avoid immune complications. Liquid-preserved reagent RBCs with known blood group antigen phenotypes are used for testing. However, these reagents have practical constraints, including limited shelf-life and require constant refrigeration. To address these issues, we explore the effects of rapid freeze-drying conditions with trehalose cryoprotectant (0.1-1 M concentrations) on human RBCs and storage of freeze-dried RBCs (FDRBCs) at room temperature (RT) for up to 12 months. We report that rapid freeze-drying of RBCs for 2.5 hr with 0.5 M trehalose achieves recoverable cells with near-normal morphological shape, although size-reduced. The FDRBCs are metabolically active and functional in antibody-agglutination tests by the column agglutination test (CAT) for ABO and Rhesus-D blood group antigens. Expression of the Duffy blood group protein (CD234) decreases by 50% after freeze-drying RBCs. The initial recovery rate is ≤25%; however, 43% of these FDRBCs are still recoverable after RT storage for 12 months. In this proof-of-principle study, we show that rapid freeze-drying can stabilize RBCs. Further refinements to improve the recovery rate and preservation of antigenic epitopes will make FDRBCs a practical alternative source of reagent RBCs for pre-transfusion alloantibody identification.