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Maedica Dec 2021RhD alloimmunization remains a severe problem worldwide, but its management has been revolutionized by two important discoveries: the possibility to establish fetal Rh...
RhD alloimmunization remains a severe problem worldwide, but its management has been revolutionized by two important discoveries: the possibility to establish fetal Rh genotype non-invasively by using a maternal blood sample, and using of Doppler velocimetry to monitor early signs of affected fetuses. We performed a literature review by searching PubMed for relevant information about diagnosis, prognosis, and management of secondary affected Rh alloimmunized pregnancies. The risk to develop fetal anemia and hydrops seems to increase with increasing concentrations of Rh antibodies, and studies show it is higher for subsequent pregnancies. Individuals presenting the DEL phenotype with the types 1, 2 or 3 can be considered RhD positive and anti-D immune globulin is not indicated. Medical algorithm involves previous pregnancy history together with serum parameters. Follow-up in a department of maternal fetal medicine is desired and encouraged in these cases. Depending on the severity and woman's previous pregnancy history, especially condition prior to 24 weeks of gestation, several therapies such as plasmaphereses, intravenous immune globulin or intrauterine transfusions can be conducted. Intrauterine transfusions have a better prognosis when performed earlier and on fetuses without hydrops. Although the incidence of hemolytic disease of the fetus and newborn has decreased and is no longer a major cause of perinatal mortality, vigilance is still required. There is a strong argument for reunite the management of these cases in dedicated maternal fetal medicine centers that perform invasive procedures in order to improve knowledge, gain skills and enhance clinical management.
PubMed: 35261671
DOI: 10.26574/maedica.2020.16.4.681 -
Nature Reviews. Nephrology Aug 2016The development of post-transplantation antibodies against non-HLA autoantigens is associated with rejection and decreased long-term graft survival. Although our... (Review)
Review
The development of post-transplantation antibodies against non-HLA autoantigens is associated with rejection and decreased long-term graft survival. Although our knowledge of non-HLA antibodies is incomplete, compelling experimental and clinical findings demonstrate that antibodies directed against autoantigens such as angiotensin type 1 receptor, perlecan and collagen, contribute to the process of antibody-mediated acute and chronic rejection. The mechanisms that underlie the production of autoantibodies in the setting of organ transplantation is an important area of ongoing investigation. Ischaemia-reperfusion injury, surgical trauma and/or alloimmune responses can result in the release of organ-derived autoantigens (such as soluble antigens, extracellular vesicles or apoptotic bodies) that are presented to B cells in the context of the transplant recipient's antigen presenting cells and stimulate autoantibody production. Type 17 T helper cells orchestrate autoantibody production by supporting the proliferation and maturation of autoreactive B cells within ectopic tertiary lymphoid tissue. Conversely, autoantibody-mediated graft damage can trigger alloimmunity and the development of donor-specific HLA antibodies that can act in synergy to promote allograft rejection. Identification of the immunologic phenotypes of transplant recipients at risk of non-HLA antibody-mediated rejection, and the development of targeted therapies to treat such rejection, are sorely needed to improve both graft and patient survival.
Topics: Autoantibodies; Autoantigens; Collagen; Heparan Sulfate Proteoglycans; Humans; Kidney Transplantation; Receptor, Angiotensin, Type 1; Transplantation Immunology
PubMed: 27345243
DOI: 10.1038/nrneph.2016.88 -
Journal of Immunological Methods Feb 2022Antibody-mediated rejection is a major cause of graft failure in organ transplantation. For this reason, B cell responses are of particular interest to transplantation...
Antibody-mediated rejection is a major cause of graft failure in organ transplantation. For this reason, B cell responses are of particular interest to transplantation research. Rats are important model organisms for transplant studies, but B cell alloimmune assays and B cell subset markers are poorly established in rats. We alloimmunized rats by donor blood injection using the high responder rat strain combination Brown Norway (donor) and Lewis (recipient) rats. Using splenocytes from alloimmunized and control rats, we established assays to assess allospecific B cell proliferation and the capacity to generate allospecific B memory cells and alloantibody-secreting cells after antigenic rechallenge in vitro using a mixed lymphocyte reaction. Furthermore, we defined a simple gating and sorting strategy for pre- and post-germinal center follicular B cells, as well as non-switched and switched plasmablasts. Our protocols for assessing B cell alloresponses and B cell subsets in rats may help to accelerate research into the role of B cells and manipulation of humoral alloresponses in transplant research.
Topics: Animals; B-Lymphocytes; Cell Proliferation; Cells, Cultured; Graft Rejection; Immunity, Humoral; Immunologic Memory; Isoantibodies; Isoantigens; Lymphocyte Activation; Male; Memory B Cells; Phenotype; Rats, Inbred BN; Rats, Inbred Lew; Rats
PubMed: 34971633
DOI: 10.1016/j.jim.2021.113212 -
Transfusion and Apheresis Science :... Feb 2020Non-invasive fetal HPA-1a typing is a valuable tool to identify the pregnancies at risk of fetal and neonatal alloimmune thrombocytopenia (FNAIT). At present, prenatal... (Review)
Review
Non-invasive fetal HPA-1a typing is a valuable tool to identify the pregnancies at risk of fetal and neonatal alloimmune thrombocytopenia (FNAIT). At present, prenatal determination of the fetus HPA-1a type is performed for diagnostic purposes in pregnancies of HPA-1 alloimmunized women with history of a previous fetus or child with FNAIT. Different approaches have been used to determine the fetal HPA-1a genotype from cell-free fetal DNA (cffDNA) in the mother's plasma, mainly based on real-time PCR. Due to the single nucleotide polymorphism (SNP) between the HPA-1a and HPA-1b allelic sequences, a robust and accurate detection of the fetal genotype is challenging, and the sensitivity of most assays is still limited early in pregnancy. Nowadays, the availability of technologies such as next generation sequencing (NGS) or digital PCR offers unprecedented possibilities of analyzing cell-free DNA (cfDNA)-amplified sequences with very high coverage and high sensitivity. In addition, other interesting approaches using variant sequence enrichment strategies have been recently described. In particular, coamplification at lower denaturation temperature PCR (COLD-PCR) offers a simple and sensitive strategy for noninvasive fetal HPA-1 typing. These novel approaches are explained in more detail in this review. Despite no population-based FNAIT screening programs have so far been implemented, the perspectives in terms of treatment and prevention are changing and less costly high-throughput maternal HPA-1a typing methods have been developed. Altogether, this may lead to the implementation of fetal HPA-1a typing with a broader scope in the future, playing a critical role within FNAIT screening programs.
Topics: Antigens, Human Platelet; Female; Fetus; Humans; Integrin beta3; Pregnancy; Thrombocytopenia, Neonatal Alloimmune
PubMed: 31953107
DOI: 10.1016/j.transci.2019.102708 -
Hematology. American Society of... Dec 2016Red blood cell (RBC) transfusions are critical for treatment and prevention of complications of sickle cell disease (SCD), and most SCD patients will receive 1 or more... (Review)
Review
Red blood cell (RBC) transfusions are critical for treatment and prevention of complications of sickle cell disease (SCD), and most SCD patients will receive 1 or more transfusions by age 20. However, SCD alloimmunization remains a serious complication of transfusions that can lead to life-threatening acute and delayed transfusion reactions. Alloimmunization rates are higher in SCD patients most likely due to RBC antigenic differences between largely white donors vs mainly African-American recipients and frequency of transfusions. However, it remains unclear why some but not all SCD patients develop alloantibodies. Cellular immune responses that differ between alloimmunized and nonalloimmunized SCD patients are beginning to be characterized. Altered CD4 T helper cell responses, known to control immunoglobulin G production, have been identified in alloimmunized SCD patients, including abnormalities in regulatory T cells, as well as helper type 1 (T1), T17, and follicular helper T cells. Furthermore, heightened innate immune cell responses to cell free heme with cell polarization toward proinflammatory T cell profiles were recently reported in SCD antibody responders, suggesting that the ongoing hemolytic state in SCD may impair the ability of innate immune cells in these already alloimmunized patients to counter alloimmunization. Identification of molecular pathways in key cellular components that differ between alloimmunized and nonalloimmunized SCD patients is likely to lead to identification of biomarkers of alloimmunization and future design of targeted therapies to prevent or even dampen alloantibody responses in these highly susceptible patients.
Topics: Anemia, Sickle Cell; Animals; Erythrocyte Transfusion; Erythrocytes; Humans; Immunization; Isoantibodies; Isoantigens; Th1 Cells; Th17 Cells
PubMed: 27913516
DOI: 10.1182/asheducation-2016.1.457 -
Transfusion Medicine and Hemotherapy :... Oct 2018Antibodies to human neutrophil antigens (HNAs) have been implicated in transfusion-related acute lung injury and allo- and autoimmune neutropenia. To date, five HNA... (Review)
Review
BACKGROUND AND OBJECTIVE
Antibodies to human neutrophil antigens (HNAs) have been implicated in transfusion-related acute lung injury and allo- and autoimmune neutropenia. To date, five HNA systems are assigned, and during the last decades enormous efforts have been undertaken to identify the underlying genes and to characterize the antigens. This review of the literature will provide the current genetic, molecular and functional information on HNAs.
RECENT FINDINGS
New information on alleles and antigens has been added to nearly each of the five HNA systems. HNA-1d has been added as the antithetical epitope to HNA-1c that is located on the glycoprotein encoded by but not by and now are included as new alleles. A substitution was demonstrated as the main reason for the HNA-2-negative phenotype on neutrophils. The target glycoprotein of HNA-3 antibodies could be identified as choline transporter-like protein 2 (CTL2) encoded by The conformation sensitive epitope discriminates between arginine and glutamine at position 152 resulting in HNA-3a and HNA-3b. An additional Leu151Phe substitution can impair HNA-3a antibody binding. Recently an alloantibody against HNA-4b which discriminates from HNA-4a by an Arg61His exchange of the glycoprotein encoded by the gene was reported in neonatal alloimmune neutropenia. An update of the current HNA nomenclature based on the new findings was provided in 2016 by the ISBT Granulocyte Immunobiology Working Party nomenclature subcommittee.
CONCLUSIONS
The molecular basis of each of the five HNA antigen systems has been decoded during the past decades. This enables reliable molecular typing strategies, antibody detection and specification as well as development of new assays based on recombinant antigens. However, research on HNA alleles, antigens, and antibodies is not finally terminated and also in the future will add new findings.
PubMed: 30498408
DOI: 10.1159/000491031 -
Immunologic Research May 2014H-Y antigens are a group of minor histocompatibility antigens encoded on the Y-chromosome with homologous H-X antigens on the X-chromosome. The disparate regions of the... (Review)
Review
H-Y antigens are a group of minor histocompatibility antigens encoded on the Y-chromosome with homologous H-X antigens on the X-chromosome. The disparate regions of the H-Y antigens are highly immunogenic and play an important role in understanding human alloimmunity. In this review, we investigate the history of H-Y antigen discovery along with their critical contributions in transplantation and pregnancy. In hematopoietic cell transplantation, male recipients with female donors who become seropositive for B-cell responses as H-Y antibodies following transplantation have increased rates of chronic graft-versus-host disease and decreased rates of relapse. Conversely, female patients who receive male kidney allografts are more likely than other gender combinations to develop H-Y antibodies and reject their allografts. Finally, in the setting of pregnancy, mothers who initially gave birth to boys are more likely to have subsequent pregnancy complications, including miscarriages, in association with H-Y antibody development. H-Y antigens continue to serve as a model for alloimmunity in new clinical scenarios. Our development of more sensitive antibody detection and next-generation DNA sequencing promises to further advance our understanding and better predict the clinical consequences of alloimmunity.
Topics: Abortion, Habitual; Animals; B-Lymphocytes; Female; Graft Rejection; Graft vs Host Disease; H-Y Antigen; Hematopoietic Stem Cell Transplantation; Histocompatibility; Humans; Isoantibodies; Male; Organ Transplantation; Pregnancy; Sex Factors; T-Lymphocytes; Transplantation Immunology
PubMed: 24781195
DOI: 10.1007/s12026-014-8514-3 -
Current Opinion in Hematology Nov 2020The purpose of this review is to summarize the role of complement in regulating the removal of a target alloantigen following an incompatible red blood cell (RBC)... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to summarize the role of complement in regulating the removal of a target alloantigen following an incompatible red blood cell (RBC) transfusion, the formation of alloantibodies following RBC alloantigen exposure, and the development of hyperhemolysis in patients with sickle cell disease (SCD).
RECENT FINDINGS
Recent studies demonstrate that complement can accelerate alloantibody-mediated removal of target alloantigens from the RBC surface following incompatible transfusion. Complement also influences alloantigen availability during developing alloimmune responses and serves as a unique mediator of CD4 T-cell-independent alloantibody formation following RBC alloantigen exposure. Finally, alternative complement pathway activation appears to play a key role in the development of acute hemolytic episodes in patients with SCD, providing a potential druggable target to prevent acute complications in patients with this disease.
SUMMARY
Recent studies suggest that complement can regulate a wide variety of processes germane to hematology, from transfusion complications to baseline hemolysis in patients with SCD. As the role of complement in various disease processes becomes more fully understood, the ability to leverage recently developed complement modulating drugs will only continue to enhance providers' ability to favorably intervene in many hematological diseases.
Topics: Anemia, Hemolytic, Autoimmune; Animals; Blood Group Incompatibility; Complement System Proteins; Erythrocyte Transfusion; Erythrocytes; Hemolysis; Humans; Isoantibodies; Isoantigens
PubMed: 32889827
DOI: 10.1097/MOH.0000000000000610 -
The Journal of Clinical Investigation Oct 2022Bronchiolitis obliterans syndrome (BOS) is a major impediment to lung transplant survival and is generally resistant to medical therapy. Extracorporeal photophoresis...
Bronchiolitis obliterans syndrome (BOS) is a major impediment to lung transplant survival and is generally resistant to medical therapy. Extracorporeal photophoresis (ECP) is an immunomodulatory therapy that shows promise in stabilizing BOS patients, but its mechanisms of action are unclear. In a mouse lung transplant model, we show that ECP blunts alloimmune responses and inhibits BOS through lowering airway TGF-β bioavailability without altering its expression. Surprisingly, ECP-treated leukocytes were primarily engulfed by alveolar macrophages (AMs), which were reprogrammed to become less responsive to TGF-β and reduce TGF-β bioavailability through secretion of the TGF-β antagonist decorin. In untreated recipients, high airway TGF-β activity stimulated AMs to express CCL2, leading to CCR2+ monocyte-driven BOS development. Moreover, we found TGF-β receptor 2-dependent differentiation of CCR2+ monocytes was required for the generation of monocyte-derived AMs, which in turn promoted BOS by expanding tissue-resident memory CD8+ T cells that inflicted airway injury through Blimp-1-mediated granzyme B expression. Thus, through studying the effects of ECP, we have identified an AM functional plasticity that controls a TGF-β-dependent network that couples CCR2+ monocyte recruitment and differentiation to alloimmunity and BOS.
Topics: Animals; Bronchiolitis Obliterans; Decorin; Granzymes; Lung Transplantation; Macrophages, Alveolar; Mice; Monocytes; Receptors, CCR2; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta
PubMed: 36189800
DOI: 10.1172/JCI159229 -
African Journal of Laboratory Medicine 2020Erythrocyte alloimmunisation can lead to complications such as delayed haemolytic transfusion reaction.
BACKGROUND
Erythrocyte alloimmunisation can lead to complications such as delayed haemolytic transfusion reaction.
OBJECTIVE
This study investigated the prevalence of and risk factors for red blood cell alloimmunisation among multiply transfused sickle cell disease (SCD) patients in Mwanza City, Tanzania.
METHODS
From May 2017 to July 2017, this descriptive, cross-sectional, hospital-based study enrolled 200 participants with SCD who had received at least two units of blood in the previous year. Blood count was performed using a Sysmex haematology analyser. Antibody screening was done by the tube method using a panel of three screening cells with known antigenicity.
RESULTS
Of the 200 patients enrolled, 108 (54%) were female. The median age was 4.5 years (interquartile range [IQR] = 6), the median number of transfusions was 3 (IQR = 1), and the median pre-transfusion haemoglobin level was 6.6 g/dl (IQR = 2.7). Prevalence of alloimmunisation was 8.5% (17/200) with immunoglobulin G, and one patient developed cold immunoglobulin M antibodies. Blood groups reported were Rhesus C and E, Kell, Kidd and Duffy. There was no statistically significant association between the number of transfusions and the risk of alloimmunisation.
CONCLUSION
The rate of alloimmunisation in multiply transfused SCD patients was 8.5% and higher than other studies in East Africa. Thus, there is a need for extensive red blood cell screening and matching to minimize alloimmunisation and risk of delayed haemolytic transfusion reaction, particularly in SCD and chronically transfused patients.
PubMed: 33102164
DOI: 10.4102/ajlm.v9i1.823