Dynamics of antibody engagement of red blood cells and .

Exposure to allogenic red blood cells (RBCs), either through pregnancy or transfusion, can result in alloimmunization, which can lead to severe hemolytic transfusion reactions and pregnancy complications. Passively administered antibodies can be used to prevent alloimmunization, where steric hindrance of allogeneic epitopes has been postulated as one mechanism whereby antibody engagement may prevent RBC alloimmunization. However, the dynamics of antibody engagement on the RBC surface has remained difficult to study.

[Neonatal Fc receptor : role and implications in maternal fetal medicine].

During pregnancy, the mother's IgG immunoglobulins cross the -placenta via the neonatal Fc receptor (FcRn), enabling the fetus to acquire passive immunity. In the presence of maternal allo- or auto-antibodies, placental transfer of these pathogenic antibodies mediated by FcRn can cause diseases in the fetus and/or the newborn. FcRn blockade therefore appears to be a therapeutic strategy in these high-risk pregnancies, firstly by reducing IgG recycling, -thereby reducing its concentration in the maternal circulation, and secondly by blocking placental transfer.

Prophylactic red cell transfusions for sickle cell disease pregnancy: increased use of therapy could transform outcomes.

Purpose Of Review: Pregnancy for people with sickle cell disease (SCD) is high risk with persistently high rates of severe maternal and fetal mortality and morbidity. Transfusion therapy is the best-studied treatment for SCD in pregnancy; hydroxyurea is not usually used because of teratogenicity concerns. In high-resource settings, red cell transfusions are likely underutilized, while in low-resource settings, they may be altogether unavailable.

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.

Approach to Pregnancy Affected by Kell Alloimmunization.

Hemolytic disease of the fetus and newborn (HDFN) is the development of anemia, hyperbilirubinemia, and finally hydrops fetalis in the fetus when antibodies to antigens on the surface of erythrocytes are transferred from the placenta to the fetus. The most common cause is D-HDFN. K (KEL1) from the Kell blood group system is the most potent immunogenic antigen after D among all blood group antigens.

Comparison of the Detection Rate and Specificity of Irregular Red Blood Cell Antibodies Between First-Time Pregnant Women and Women With a History of Multiple Pregnancies Among 18,010 Chinese Women.

There is insufficient evidence to assess the risk of the production of clinically important alloimmune irregular red blood cell (RBC) antibodies in first-time pregnant women. Using the microcolumn gel antiglobulin method, 18,010 Chinese women with a history of pregnancy and pregnant women were screened for irregular RBC antibodies, and for those with positive test results, antibody specificity was determined. The detection rate and specificity of irregular RBC antibodies in women with a history of multiple pregnancies (two or more) and first-time pregnant women were determined.

Alloimmune Conditions in the Neonatal Foal.

Alloimmune disorders occur in foals when pregnant mares produce antibodies against antigens on the foal's cells or tissues, and concentrate them within colostrum. Once foals nurse and absorb colostral antibodies, they can develop hematologic or cutaneous manifestations that can occur individually or in combination. These include neonatal isoerythrolysis, a hemolytic anemia directed against factors on the foal's erythrocytes, alloimmune thrombocytopenia when the antibodies are directed against platelet antigens, alloimmune neutropenia when they are directed against neutrophil antigens, and a combination of suspected alloimmune ulcerative dermatitis, neutropenia and thrombocytopenia.

The influence of HLA allele and haplotype on RhE alloimmunization among pregnant females in the Chinese Han population.

Background And Objectives: Anti-E alloantibody is the most common and important red blood cell (RBC) alloantibody during pregnancy. The study aimed to determine the correlation between RhE alloimmunization and human leukocyte antigen (HLA) allele polymorphism, as well as haplotype diversity, among pregnant individuals in the Chinese Han population.

Study Design And Methods: All individuals included in our study were RhE-negative pregnant women of Chinese Han ethnicity, confirmed through serological testing.

Evidence that CD36 is expressed on red blood cells and constitutes a novel blood group system of clinical importance.

Background And Objectives: Polymorphic molecules expressed on the surface of certain blood cells are traditionally categorized as blood groups and human platelet or neutrophil antigens. CD36 is widely considered a platelet antigen (Nak) and anti-CD36 can cause foetal/neonatal alloimmune thrombocytopenia (FNAIT) in CD36-negative pregnant women. CD36 is used as a marker of differentiation in early erythroid culture.

Frequency and Underlying Causes of Alloimmunization Against Red Blood Cell Antigens in Patients Referred to the Blood Bank of the Tertiary Referral Hospital of Tehran from 2018 to 2020.

Background: Alloimmunization against blood group antigens is an important non-infectious complication of blood transfusion, and early detection of these alloantibodies by antibody screening before transfusion is crucial. Identifying which underlying factors will affect the occurrence of alloimmunization will be necessary to manage this event as accurately as possible. We aimed to assess the prevalence rate and main determinants of RBC alloimmunization among patients referred to a large referral blood bank in Iran.

Hemolytic disease of the fetus and newborn due to minor blood group alloimmunization in a mother of sickle cell disease with multiple alloantibodies.

Hemolytic disease of the fetus and newborn is due to maternal IgG antibodies that transport through the placenta and destroy neonatal red cells. A mismatch of antigens between mother and fetus causes isoimmunization resulting in mild anemia, which may progress to fetal hydrops in the intrauterine period and severe hyperbilirubinemia to kernicterus in neonates. The isoimmunization is mainly caused by Rh-D and ABO antibodies.

Placental Histopathologic Findings in Fetal Hereditary Pyropoikilocytosis after Undergoing Successful Intrauterine Transfusion.

The available literature on intrauterine transfusion focuses largely on its application in fetal alloimmunization rather than hereditary red cell disorders, with limited illustration of its associated histopathologic findings. We present the histologic findings in a placenta associated with preterm delivery of an infant with autosomal mutation following multiple intrauterine transfusions, including appropriate villous maturation, subchorionic organizing hematomas, hemosiderin-laden macrophages, and dysmorphic fetal erythrocytes within villous capillaries. Intrauterine transfusion is associated with placental histologic findings that reflect procedural changes without significant disruption of placental membranes or villous maturation.

Automated quantitative evaluation of fetal atrioventricular annular plane systolic excursion before and after intrauterine blood transfusion in pregnancies affected by red blood cell alloimmunization.

Introduction: Maternal red blood cell alloimmunization during pregnancy can lead to hemolysis and various degrees of fetal anemia, which can be treated with intrauterine blood transfusion (IUT) to prevent adverse outcomes. Knowledge about fetal myocardial function and adaptation is limited. The aim of the present study was to measure fetal atrioventricular plane displacement before and after IUT and compare these measurements with previously established reference ranges.

Immunohematological testing and transfusion management of the prenatal patient.

The primary indication for immunohematological testing in the prenatal patient is to detect and identify maternal red cell antibodies. If there are antibodies that are expected to hemolyze the fetus' red cells, their strength of reactivity must be tested, and the fetus' antigen status determined. After delivery, testing is performed to assess the extent of fetomaternal hemorrhage, as a large hemorrhage may require other therapeutic interventions.

Trogocytosis drives red blood cell antigen loss in association with antibody-mediated immune suppression.

Red blood cell (RBC) alloimmunization to paternal antigens during pregnancy can cause hemolytic disease of the fetus and newborn (HDFN). This severe and potentially fatal neonatal disorder can be prevented by the administration of polyclonal anti-D through a mechanism referred to as antibody-mediated immune suppression (AMIS). Although anti-D prophylaxis effectively prevents HDFN, a lack of mechanistic clarity has hampered its replacement with recombinant agents.

Alloimmune hemolytic disease of the fetus and newborn: genetics, structure, and function of the commonly involved erythrocyte antigens.

Hemolytic disease of the fetus and newborn (HDFN) can occur when a pregnant woman has antibody directed against an erythrocyte surface antigen expressed by her fetus. This alloimmune disorder is restricted to situations where transplacental transfer of maternal antibody to the fetus occurs, and binds to fetal erythrocytes, and significantly shortens the red cell lifespan. The pathogenesis of HDFN involves maternal sensitization to erythrocyte "non-self" antigens (those she does not express).