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Gao C, Chen Q, Hao X, Wang Q. Immunomodulation of Antibody Glycosylation through the Placental Transfer. Int J Mol Sci 2023; 24:16772. [PMID: 38069094 PMCID: PMC10705935 DOI: 10.3390/ijms242316772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Establishing an immune balance between the mother and fetus during gestation is crucial, with the placenta acting as the epicenter of immune tolerance. The placental transfer of antibodies, mainly immunoglobulin G (IgG), is critical in protecting the developing fetus from infections. This review looks at how immunomodulation of antibody glycosylation occurs during placental transfer and how it affects fetal health. The passage of maternal IgG antibodies through the placental layers, including the syncytiotrophoblast, stroma, and fetal endothelium, is discussed. The effect of IgG subclass, glycosylation, concentration, maternal infections, and antigen specificity on antibody transfer efficiency is investigated. FcRn-mediated IgG transport, influenced by pH-dependent binding, is essential for placental transfer. Additionally, this review delves into the impact of glycosylation patterns on antibody functionality, considering both protective and pathological effects. Factors affecting the transfer of protective antibodies, such as maternal vaccination, are discussed along with reducing harmful antibodies. This in-depth examination of placental antibody transfer and glycosylation provides insights into improving neonatal immunity and mitigating the effects of maternal autoimmune and alloimmune conditions.
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Affiliation(s)
| | | | | | - Qiushi Wang
- Department of Blood Transfusion, Shengjing Hospital of China Medical University, Shenyang 110004, China
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2
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Abstract
A diagnosis of fetal/neonatal alloimmune thrombocytopenia (FNAIT) is made if a platelet-specific antibody is detected in the mother and the fetus or newborn carries the cognate antigen. Some children will experience very low platelet counts or even intracranial hemorrhage with devastating consequences, whereas others are largely unaffected. At the moment, predictive tools to forecast the severity of FNAIT during pregnancy are not available and over- or under-treatment may put the mother or the fetus at risk. A number of potential modulators of FNAIT severity have been reported. Maternal immune responses differ in respect to the IgG subtype composition, the glycosylation pattern of the antibodies, their fine specificity, and their functional effects on platelets, the trophoblast, and endothelial cells. In addition, antibody levels are variable. The efficacy of IgG transfer and, on the fetal side, gender and inflammatory responses, were also investigated for their potential impact on FNAIT severity. These potential risk modulators are scrutinized for available experimental and clinical evidence. Antibody glycosylation and anti-endothelial activity are hot candidates which, most likely in conjunction with the antibody level, should be explored further as tools to stratify fetal risk.
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Affiliation(s)
- Ulrich J Sachs
- Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany; Center for Transfusion Medicine and Hemotherapy, University Hospital Giessen and Marburg, Marburg, Germany; German Center for Fetomaternal Incompatibility (DZFI), University Hospital Giessen and Marburg, Giessen, Germany.
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3
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Kjaer M, Bertrand G, Bakchoul T, Massey E, Baker JM, Lieberman L, Tanael S, Greinacher A, Murphy MF, Arnold DM, Baidya S, Bussel J, Hume H, Kaplan C, Oepkes D, Ryan G, Savoia H, Shehata N, Kjeldsen-Kragh J. Maternal HPA-1a antibody level and its role in predicting the severity of Fetal/Neonatal Alloimmune Thrombocytopenia: a systematic review. Vox Sang 2018; 114:79-94. [PMID: 30565711 DOI: 10.1111/vox.12725] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/05/2018] [Accepted: 10/19/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES In Caucasians, fetal/neonatal alloimmune thrombocytopenia (FNAIT) is most commonly due to maternal HPA-1a antibodies. HPA-1a typing followed by screening for anti-HPA-1a antibodies in HPA-1bb women may identify first pregnancies at risk. Our goal was to review results from previous published studies to examine whether the maternal antibody level to HPA-1a could be used to identify high-risk pregnancies. MATERIALS AND METHODS The studies included were categorized by recruitment strategies: screening of unselected pregnancies or samples analyzed from known or suspected FNAIT patients. RESULTS Three prospective studies reported results from screening programmes, and 10 retrospective studies focused on suspected cases of FNAIT. In 8 studies samples for antibody measurement, performed by the monoclonal antibody immobilization of platelet antigen (MAIPA) assay, and samples for determining fetal/neonatal platelet count were collected simultaneously. In these 8 studies, the maternal antibody level correlated with the risk of severe thrombocytopenia. The prospective studies reported high negative predictive values (88-95%), which would allow for the use of maternal anti-HPA-1a antibody level as a predictive tool in a screening setting, in order to identify cases at low risk for FNAIT. However, due to low positive predictive values reported in prospective as well as retrospective studies (54-97%), the maternal antibody level is less suited for the final diagnosis and for guiding antenatal treatment. CONCLUSION HPA-1a antibody level has the potential to predict the severity of FNAIT.
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Affiliation(s)
- Mette Kjaer
- Department of Laboratory Medicine, Diagnostic Clinic, University Hospital of North Norway, Tromsø, Norway
- Finnmark Hospital Trust, Finnmark, Norway
| | - Gerald Bertrand
- Platelet Immunology Department, French Blood Services of Brittany, Rennes, France
| | - Tamam Bakchoul
- Center for Clinical Transfusion Medicine, University of Tuebingen, Tuebingen, Germany
- Institute of Immunology and Transfusion Medicine, University Hospital Greifswald, Greifswald, Germany
| | | | - Jillian M Baker
- Hospital for Sick Children, St. Michael's Hospital, Toronto, ON, Canada
| | - Lani Lieberman
- University Health Network, University of Toronto, Toronto, ON, Canada
| | - Susano Tanael
- Center for Innovation, Canadian Blood Services, Toronto, ON, Canada
| | - Andreas Greinacher
- Institute of Immunology and Transfusion Medicine, University Hospital Greifswald, Greifswald, Germany
| | - Michael F Murphy
- NHS Blood and Transplant, Oxford University Hospitals and University of Oxford, Oxford, UK
| | - Donald M Arnold
- Division of Hematology and Thromboembolism, McMaster University, Hamilton, ON, Canada
| | - Shoma Baidya
- Australian Red Cross Blood Service, Brisbane, QLD, Australia
| | | | - Heather Hume
- Division of Hematology-Oncology, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, QC, Canada
| | - Cécile Kaplan
- Institut National de la Transfusion Sanguine, Paris, France
| | - Dick Oepkes
- Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Greg Ryan
- Fetal Medicine Unit, Mount Sinai Hospital, Toronto, ON, Canada
| | - Helen Savoia
- Royal Children's Hospital, Melbourne, VIC, Australia
| | - Nadine Shehata
- Center for Innovation, Canadian Blood Services, Toronto, ON, Canada
- Department of Medicine, Mount Sinai Hospital, Toronto, ON, Canada
- Department of Obstetric Medicine, Mount Sinai Hospital, Toronto, ON, Canada
| | - Jens Kjeldsen-Kragh
- Department of Laboratory Medicine, Diagnostic Clinic, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Immunology and Transfusion Medicine, Regional and University Laboratories Region Skåne, Lund, Sweden
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4
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Sachs UJ, Santoso S. Bleeding or no bleeding? Anti-endothelial alphaVbeta3 antibodies as a major cause of intracranial haemorrhage in fetal-neonatal alloimmune thrombocytopenia. ACTA ACUST UNITED AC 2017. [DOI: 10.1111/voxs.12401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- U. J. Sachs
- Institute for Clinical Immunology and Transfusion Medicine; Justus Liebig University; Giessen Germany
- Center for Transfusion Medicine and Hemotherapy; University Hospital Giessen and Marburg; Marburg Germany
- German Center for Fetomaternal Incompatibility (DZFI); University Hospital Giessen and Marburg; Giessen Germany
| | - S. Santoso
- Institute for Clinical Immunology and Transfusion Medicine; Justus Liebig University; Giessen Germany
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5
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[Thirty years of platelet immunology in fetal and neonatal alloimmune thrombocytopenia management, current situation]. Transfus Clin Biol 2017; 24:166-171. [PMID: 28673503 DOI: 10.1016/j.tracli.2017.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 11/21/2022]
Abstract
Fetal and neonatal allo-immune thrombocytopenia (FNAIT) is considered as a rare disease due to the incidence (1/1000-1/2000 births). The major complication of severe thrombocytopenia is bleeding and particularly intra-cranial hemorrhage and neurologic sequelae following. Serology and molecular biology developments have reconfigured the platelet immunology diagnosis. Anti-HPA-1a allo-immunisation is responsible for more than 80% FNAIT cases with a high recurrence rate of severe bleeding complications. Therapeutic management has changed over the coming years from an invasive concept associating fetal blood sampling and in utero platelet transfusion to a non invasive treatment by intravenous immunoglobulins injection (IVIg). The purpose of this article is to provide an update on FNAIT management in the light of current developments over the past 30years.
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Sonneveld ME, van der Schoot CE, Vidarsson G. The Elements Steering Pathogenesis in IgG-Mediated Alloimmune Diseases. J Clin Immunol 2016; 36 Suppl 1:76-81. [PMID: 26961360 DOI: 10.1007/s10875-016-0253-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 02/23/2016] [Indexed: 02/05/2023]
Abstract
Alloimmune diseases can occur in pregnancy and after blood transfusions, where antibodies are formed, targeting foreign cells and tissues for destruction by myeloid cells through IgG Fc-receptors (FcγR). In pregnancy, antibodies against human blood group or platelet antigens (e.g. HPA1-a) cause life-threatening anemia or thrombocytopenia in the developing fetus or newborn. Here we discuss how both the induction of those IgG antibodies as well as the proinflammatory status of the fetus affects the effector functions through FcγR. Recent studies have found IgG-glycosylation to be important with low IgG-Fc-core fucosylation resulting in increased affinity to FcγRIIIa and FcγRIIIb and enhanced antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis. The importance of these and other features, including oxidative stress and acute phase responses (C-reactive protein, CRP), will be discussed and how these features may collectively synergize resulting in elevated disease pathology in these allo-, but also autoimmune mediated diseases.
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Affiliation(s)
- Myrthe E Sonneveld
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Plesmanlaan 125, 1066 CX, Amsterdam, The Netherlands
| | - C Ellen van der Schoot
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Plesmanlaan 125, 1066 CX, Amsterdam, The Netherlands
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Plesmanlaan 125, 1066 CX, Amsterdam, The Netherlands.
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7
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Brojer E, Husebekk A, Dębska M, Uhrynowska M, Guz K, Orzińska A, Dębski R, Maślanka K. Fetal/Neonatal Alloimmune Thrombocytopenia: Pathogenesis, Diagnostics and Prevention. Arch Immunol Ther Exp (Warsz) 2015; 64:279-90. [PMID: 26564154 PMCID: PMC4939163 DOI: 10.1007/s00005-015-0371-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 08/31/2015] [Indexed: 01/10/2023]
Abstract
Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a relatively rare condition (1/1000–1/2000) that was granted orphan status by the European Medicines Agency in 2011. Clinical consequences of FNAIT, however, may be severe. A thrombocytopenic fetus or new-born is at risk of intracranial hemorrhage that may result in lifelong disability or death. Preventing such bleeding is thus vital and requires a solution. Anti-HPA1a antibodies are the most frequent cause of FNAIT in Caucasians. Its pathogenesis is similar to hemolytic disease of the newborn (HDN) due to anti-RhD antibodies, but is characterized by platelet destruction and is more often observed in the first pregnancy. In 75 % of these women, alloimmunization by HPA-1a antigens, however, occurs at delivery, which enables development of antibody-mediated immune suppression to prevent maternal immunization. As for HDN, the recurrence rate of FNAIT is high. For advancing diagnostic efforts and treatment, it is thereby crucial to understand the pathogenesis of FNAIT, including cellular immunity involvement. This review presents the current knowledge on FNAIT. Also described is a program for HPA-1a screening in identifying HPA-1a negative pregnant women at risk of immunization. This program is now performed at the Institute of Hematology and Transfusion Medicine in cooperation with the Department of Obstetrics and Gynecology of the Medical Centre of Postgraduate Education in Warsaw as well as the UiT The Arctic University of Norway.
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Affiliation(s)
- Ewa Brojer
- Department of Immunohematology and Immunology of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland.
| | - Anne Husebekk
- Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Marzena Dębska
- 2nd Department of Obstetrics and Gynecology, Medical Centre of Postgraduate Education, Warsaw, Poland
| | - Małgorzata Uhrynowska
- Department of Immunohematology and Immunology of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Katarzyna Guz
- Department of Immunohematology and Immunology of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Agnieszka Orzińska
- Department of Immunohematology and Immunology of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Romuald Dębski
- 2nd Department of Obstetrics and Gynecology, Medical Centre of Postgraduate Education, Warsaw, Poland
| | - Krystyna Maślanka
- Department of Immunohematology and Immunology of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
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Vidarsson G, Dekkers G, Rispens T. IgG subclasses and allotypes: from structure to effector functions. Front Immunol 2014; 5:520. [PMID: 25368619 PMCID: PMC4202688 DOI: 10.3389/fimmu.2014.00520] [Citation(s) in RCA: 1656] [Impact Index Per Article: 165.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 10/06/2014] [Indexed: 12/21/2022] Open
Abstract
Of the five immunoglobulin isotypes, immunoglobulin G (IgG) is most abundant in human serum. The four subclasses, IgG1, IgG2, IgG3, and IgG4, which are highly conserved, differ in their constant region, particularly in their hinges and upper CH2 domains. These regions are involved in binding to both IgG-Fc receptors (FcγR) and C1q. As a result, the different subclasses have different effector functions, both in terms of triggering FcγR-expressing cells, resulting in phagocytosis or antibody-dependent cell-mediated cytotoxicity, and activating complement. The Fc-regions also contain a binding epitope for the neonatal Fc receptor (FcRn), responsible for the extended half-life, placental transport, and bidirectional transport of IgG to mucosal surfaces. However, FcRn is also expressed in myeloid cells, where it participates in both phagocytosis and antigen presentation together with classical FcγR and complement. How these properties, IgG-polymorphisms and post-translational modification of the antibodies in the form of glycosylation, affect IgG-function will be the focus of the current review.
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Affiliation(s)
- Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam , Amsterdam , Netherlands
| | - Gillian Dekkers
- Department of Experimental Immunohematology, Sanquin Research, and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam , Amsterdam , Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research, and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam , Amsterdam , Netherlands
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9
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From Donor to Recipient: Current Questions Relating to Humoral Alloimmunization. Antibodies (Basel) 2014. [DOI: 10.3390/antib3010130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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10
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Bessos H, Killie MK, Seghatchian J, Skogen B, Urbaniak SJ. The relationship of anti-HPA-1a amount to severity of neonatal alloimmune thrombocytopenia - Where does it stand? Transfus Apher Sci 2009; 40:75-8. [PMID: 19223235 DOI: 10.1016/j.transci.2009.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The issue of whether or not antibody quantity during pregnancy is related to severity of neonatal alloimmune thrombocytopenia remains unresolved. In this article we cite studies in support of both sides of the argument and highlight some of the reasons that may lie behind the observed differences amongst those studies. It may well be that some of the reasons for the discrepant results could be due to the type of study carried out (eg retrospective versus prospective), the sample size, the timing of antibody sampling, and possibly the type or protocol of assay used. Another major reason is the absence, until recently, of an international anti-HPA-1a standard.
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Affiliation(s)
- Hagop Bessos
- Research and Development Directorate, Scottish National Blood Transfusion Service, Edinburgh and Aberdeen, Scotland, UK
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Radder CM, Beekhuizen H, Kanhai HHH, Brand A. Effect of maternal anti-HPA-1a antibodies and polyclonal IVIG on the activation status of vascular endothelial cells. Clin Exp Immunol 2004; 137:216-22. [PMID: 15196265 PMCID: PMC1809094 DOI: 10.1111/j.1365-2249.2004.02496.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Maternal anti-HPA-1a antibodies can cause severe fetal and neonatal alloimmune thrombocytopenia (FNAIT), complicated by intracranial haemorrhage (ICH). Antenatal treatment with maternal intravenous immunoglobulin (IVIG) seems to protect against ICH even when thrombocytopenia persists. The aim of this study was to investigate if anti-HPA-1a antibodies and IVIG potentially affect vascular endothelial cells (ECs) in order to identify susceptibility for ICH. Human umbilical cord endothelial cells (HUVEC) were incubated with anti-HPA-1a antibodies with or without polyclonal IVIG and evaluated for EC activation. Maternal sera with anti-HPA-1a antibodies affected neither the EC expression of intracellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and tissue factor (TF) nor the release of van Willebrand factor (vWF) or interleukin (IL)-8 nor the integrity of ECs. Maternal sera obtained after IVIG treatment and polyclonal IVIG decrease constitutive and cytokine-induced ICAM-1 and VCAM-1 expression on ECs. The results show that maternal anti-HPA-1a antibodies cause no activation or damage of ECs in this model. The clinical relevance of the de-activating properties of IVIG on EC activation with respect to ICH deserves further investigation.
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Affiliation(s)
- C M Radder
- Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands.
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Kelsch R, Hutt K, Cassens U, Sibrowski W. Semiquantitative measurement of IgG subclasses and IgM of platelet-specific antibodies in a glycoprotein-specific platelet-antigen capture assay. Br J Haematol 2002; 117:141-50. [PMID: 11918546 DOI: 10.1046/j.1365-2141.2002.03375.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The detection of platelet-specific antibodies is of high clinical interest in diseases with immune thrombocytopenia. The glycoprotein-specific platelet-antigen capture (PAC)-assay developed in this study is especially suited to the differentiation of platelet-specific immunoglobulin (Ig) G subclasses and the determination of platelet-specific IgM in serum or on platelets. The problems with unspecific signals or low sensitivity usually seen with the detector antibodies available are effectively overcome, as unbound detector antibodies are removed at an early stage in the assay. We investigated 14 maternal alloantisera from cases of neonatal alloimmune thrombocytopenia (NAITP) and six sera from patients with autoimmune thrombocytopenic purpura (AITP). In NAITP sera, we found IgG1 alone in 57%, IgG1 + IgG3 in 21% and IgG1 + IgG2 in 14% of cases. One serum contained IgG1 + IgG2 + IgG3. In AITP, three out of the six sera contained IgG1 alone. One serum contained IgG1 + IgG2. One patient, with highly refractory AITP, had platelet-specific IgG1 + IgG2 + IgG3 in his serum. A patient with AITP in remission and normal platelet counts only showed platelet-bound IgG2. The detection of platelet-specific 'whole IgG' is possible too. However, at this time the commonly used monoclonal antibody-specific immobilization of platelet antigens (MAIPA) method should not be replaced for this purpose, as it is well standardized and used with similar results in many laboratories. The PAC assay sensitively detects the subclasses of platelet-specific IgG and human leucocyte antigen (HLA)-antibodies independently. It is easy to perform and takes less time than other platelet glycoprotein-specific methods.
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Affiliation(s)
- Reinhard Kelsch
- Department of Transfusion Medicine, University Hospital Münster, Germany.
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Dettke M, Dreer M, Höcker P, Panzer S. Human platelet antigen-1a antibodies induce the release of the chemokine RANTES from human platelets. Vox Sang 2001; 81:199-203. [PMID: 11703865 DOI: 10.1046/j.0042-9007.2001.00105.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE Binding of human platelet antigen-1a (HPA-1a)-specific antibodies to target platelets can trigger platelet activation and mediator release. Here we tested the effect of HPA-1a antibody-containing sera on platelet release of the chemokine RANTES (regulated on activation, normal, T-cell expressed, and presumably secreted) in vitro. PATIENTS AND METHODS HPA-1a-containing sera obtained from 11 mothers delivered of an infant with neonatal alloimmune thrombocytopenia (NAIT) and from six patients with post-transfusion purpura (PTP) were incubated with HPA-1a/a target platelets. Antibody-induced release of soluble RANTES was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS A significant release of soluble RANTES was induced by four out of the 17 sera. Two out of the four reactive sera were obtained from mothers who were delivered of a baby with NAIT and the remaining two sera were from patients with PTP. Chemokine release was specific for binding of anti-HPA-1a to the platelet membrane, as none of the reactive sera induced the release of soluble RANTES when incubated with HPA-1b/b platelets. The blockade of platelet-expressed Fc gamma receptor type II (FcgammaRII) inhibited anti-HPA-1a-mediated RANTES release when incubated with the reactive sera of patients with NAIT, but not when platelets were incubated with sera of patients with PTP. CONCLUSION Our findings suggest that anti-HPA-1a antibody-induced release of platelet-derived RANTES can play a role in adverse reactions in alloimmunized patients.
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Affiliation(s)
- M Dettke
- Department for Blood Group Serology and Transfusion Medicine, AKH Wien, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
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