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Stam W, Wachholz GE, de Pereda JM, Kapur R, van der Schoot E, Margadant C. Fetal and neonatal alloimmune thrombocytopenia: Current pathophysiological insights and perspectives for future diagnostics and treatment. Blood Rev 2022; 59:101038. [PMID: 36581513 DOI: 10.1016/j.blre.2022.101038] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
FNAIT is a pregnancy-associated condition caused by maternal alloantibodies against paternally-inherited platelet antigens, most frequently HPA-1a on integrin β3. The clinical effects range from no symptoms to fatal intracranial hemorrhage, but underlying pathophysiological determinants are poorly understood. Accumulating evidence suggests that differential antibody-Fc-glycosylation, activation of complement/effector cells, and integrin function-blocking effects contribute to clinical outcome. Furthermore, some antibodies preferentially bind platelet integrin αIIbβ3, but others bind αvβ3 on endothelial cells and trophoblasts. Defects in endothelial cells and angiogenesis may therefore contribute to severe anti-HPA-1a associated FNAIT. Moreover, anti-HPA-1a antibodies may cause placental damage, leading to intrauterine growth restriction. We discuss current insights into diversity and actions of HPA-1a antibodies, gathered from clinical studies, in vitro studies, and mouse models. Assessment of all factors determining severity and progression of anti-HPA-1a-associated FNAIT may importantly improve risk stratification and potentially reveal novel treatment strategies, both for FNAIT and other immunohematological disorders.
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Affiliation(s)
- Wendy Stam
- Institute of Biology, Leiden University, Leiden, the Netherlands; Cancer Center Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands.
| | | | - Jose Maria de Pereda
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain.
| | - Rick Kapur
- Sanquin Research, Department of Experimental Immunohematology, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
| | - Ellen van der Schoot
- Sanquin Research, Department of Experimental Immunohematology, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
| | - Coert Margadant
- Institute of Biology, Leiden University, Leiden, the Netherlands; Cancer Center Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands.
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2
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Holzwarth ST, Bayat B, Zhu J, Phuangtham R, Fischer L, Boeckelmann D, Röder L, Berghöfer H, Schmidt S, Bein G, Santoso S. Naturally occurring point mutation Cys460Trp located in the I-EGF1 domain of integrin β3 alters the binding of some anti-HPA-1a antibodies. Transfusion 2020; 60:2097-2107. [PMID: 32770549 DOI: 10.1111/trf.15960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/29/2020] [Accepted: 05/29/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is caused by the destruction of platelets in the fetus or newborn by maternal platelet alloantibodies, mostly against human platelet antigen (HPA)-1a. Recent studies indicate that two anti-HPA subtypes exist: Type I reacts with epitopes residing on the plexin-semaphorin-integrin (PSI) and type II with plexin-semaphorin-integrin/integrin epidermal growth factor 1 (I-EGF1) domains of the β3 integrin. Here, we evaluated whether a Cys460Trp mutation in the I-EGF1 domain found in a patient with Glanzmann thrombasthenia can alter the binding of anti-HPA-1a. METHODS Stable HEK293 cell lines expressing wild-type and mutant αIIbβ3 and αvβ3 were generated to prove the reactivity of different antibodies against HPA-1a. RESULTS Flow cytometry analysis of wild-type (Cys460) and mutant (Trp460) expressed on HEK293 cells showed equal surface expression of αIIbβ3 and αvβ3. When tested with mutant αIIbβ3 cells, reduced binding was observed in Type II but not in Type I anti-HPA-1a. These results could be confirmed with platelets carrying Cys460Trp mutation. Interestingly, reduced binding of Type I antibodies was detected with mutant αvβ3 cells. Both antibody types were found in maternal sera from FNAIT cases by an antigen-capture assay with use of HEK293 transfected cells. CONCLUSIONS These observations confirm the existence of Type I and Type II anti-HPA-1a. Furthermore, this study underlines different immunogenicity of HPA-1a antigen(s) residing on either αIIbβ3 or αvβ3. Further analysis of FNAIT cases from mothers having a fetus with and without intracranial bleedings with use of such an approach may highlight the functional relevance of different anti-HPA-1a subtypes.
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Affiliation(s)
- Sarah Theresa Holzwarth
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
| | - Behnaz Bayat
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
| | - Jieqing Zhu
- Blood Research Institute, Milwaukee, Wisconsin, USA
| | - Roongaroon Phuangtham
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany.,Department of Transfusion Medicine and Clinical Microbiology, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Lars Fischer
- Department of Children Oncology, Haematology and Haemostaseology, University Leipzig, Leipzig, Germany
| | - Doris Boeckelmann
- Department of Hemostaseology, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Lida Röder
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
| | - Heike Berghöfer
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
| | - Silke Schmidt
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
| | - Gregor Bein
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
| | - Sentot Santoso
- Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany
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3
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Dahl J, Skogen B, Kjaer M, Husebekk A, Kjeldsen-Kragh J, Tiller H. A combined effect of anti-HPA-1a and anti-HLA Class I in pregnancy? Transfusion 2020; 60:2121-2129. [PMID: 32608103 DOI: 10.1111/trf.15944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 12/25/2022]
Abstract
BACKGROUND Maternal anti-human leukocyte antigen (HLA) Class I is commonly detected alongside anti-human platelet antigen (HPA)-1a in fetal and neonatal alloimmune thrombocytopenia (FNAIT). Little is known regarding whether the presence of anti-HLA Class I may exert an additive effect on the risk and severity of FNAIT. METHODS AND MATERIALS We reanalyzed samples originally collected as part of a large Norwegian screening study on FNAIT during 1995-2004. This study identified and managed 170 pregnancies where the mother was HPA-1a negative and had detectable anti-HPA-1a during pregnancy. Maternal samples from 166 of these pregnancies were rescreened for anti-HLA Class I, revealing 111 (67%) that were antibody positive. Various regression models were used to assess if and how maternal anti-HLA Class I influenced the neonatal platelet count. RESULTS AND CONCLUSIONS Unadjusted neonatal platelet counts and the frequency of neonatal thrombocytopenia was not significantly affected by the presence of anti-HLA Class I alongside anti-HPA-1a, but results from regression analyses revealed a possible increased risk when the mother was nulliparous. These results warrant further investigation.
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Affiliation(s)
- Jesper Dahl
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Bjørn Skogen
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Mette Kjaer
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.,Centre for Medicine, Clinical Research and Integrated Care, Finnmark Hospital Trust, Hammerfest, Norway
| | - Anne Husebekk
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jens Kjeldsen-Kragh
- Department of Laboratory Medicine Diagnostic Clinic, University Hospital of North Norway, Tromsø, Norway.,Department of Clinical Immunology and Transfusion Medicine, University and Regional Laboratories Region Skåne, Lund, Sweden
| | - Heidi Tiller
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.,Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway
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4
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Tiller H, Ahlen MT, Akkök ÇA, Husebekk A. Fetal and neonatal alloimmune thrombocytopenia - The Norwegian management model. Transfus Apher Sci 2019; 59:102711. [PMID: 31911047 DOI: 10.1016/j.transci.2019.102711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In Norway, the management strategy for fetal and neonatal alloimmune thrombocytopenia (FNAIT) has for more than two decades differed from most other countries. The focus of this paper is to describe and discuss the Norwegian FNAIT management program. We recommend antenatal IVIg to women who previously have had a child with FNAIT-induced ICH, and usually not to HPA-1a alloimmunized pregnant women where a previous child had FNAIT, but not ICH. When deciding management strategy, we use not only the obstetric history but also the antenatal anti-HPA-1a antibody level as a tool for risk stratification. The Norwegian National Unit for Platelet Immunology (NNUPI) at the University Hospital of North Norway in Tromsø provides diagnostic and consulting service for the clinicians and the blood banks all over the country, and serves as a national reference laboratory for FNAIT investigations.
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Affiliation(s)
- Heidi Tiller
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway; Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway.
| | - Maria Therese Ahlen
- Department of Laboratory Medicine, Division of Diagnostics, University Hospital of North Norway, Tromsø, Norway
| | - Çiğdem Akalın Akkök
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway
| | - Anne Husebekk
- Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
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5
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Abstract
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a disease in pregnancy characterized by maternal alloantibodies directed against the human platelet antigen (HPA). These antibodies can cause intracranial hemorrhage (ICH) or other major bleeding resulting in lifelong handicaps or death. Optimal fetal care can be provided by timely identification of pregnancies at risk. However, this can only be done by routinely antenatal screening. Whether nationwide screening is cost-effective is still being debated. HPA-1a alloantibodies are estimated to be found in 1 in 400 pregnancies resulting in severe burden and fetal ICH in 1 in 10.000 pregnancies. Antenatal treatment is focused on the prevention of fetal ICH and consists of weekly maternal IVIg administration. In high-risk FNAIT treatment should be initiated at 12-18 weeks gestational age using high dosage and in standard-risk FNAIT at 20-28 weeks gestational age using a lower dosage. Postnatal prophylactic platelet transfusions are often given in case of severe thrombocytopenia to prevent bleedings. The optimal threshold and product for postnatal transfusion is not known and international consensus is lacking. In this review practical guidelines for antenatal and postnatal management are offered to clinicians that face the challenge of reducing the risk of bleeding in fetuses and infants affected by FNAIT.
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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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7
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Lieberman L, Greinacher A, Murphy MF, Bussel J, Bakchoul T, Corke S, Kjaer M, Kjeldsen-Kragh J, Bertrand G, Oepkes D, Baker JM, Hume H, Massey E, Kaplan C, Arnold DM, Baidya S, Ryan G, Savoia H, Landry D, Shehata N. Fetal and neonatal alloimmune thrombocytopenia: recommendations for evidence-based practice, an international approach. Br J Haematol 2019; 185:549-562. [PMID: 30828796 DOI: 10.1111/bjh.15813] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/27/2018] [Indexed: 11/28/2022]
Abstract
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) may result in severe bleeding, particularly fetal and neonatal intracranial haemorrhage (ICH). As a result, FNAIT requires prompt identification and treatment; subsequent pregnancies need close surveillance and management. An international panel convened to develop evidence-based recommendations for diagnosis and management of FNAIT. A rigorous approach was used to search, review and develop recommendations from published data for: antenatal management, postnatal management, diagnostic testing and universal screening. To confirm FNAIT, fetal human platelet antigen (HPA) typing, using non-invasive methods if quality-assured, should be performed during pregnancy when the father is unknown, unavailable for testing or heterozygous for the implicated antigen. Women with a previous child with an ICH related to FNAIT should be offered intravenous immunoglobulin (IVIG) infusions during subsequent affected pregnancies as early as 12 weeks gestation. Ideally, HPA-selected platelets should be available at delivery for potentially affected infants and used to increase the neonatal platelet count as needed. If HPA-selected platelets are not immediately available, unselected platelets should be transfused. FNAIT studies that optimize antenatal and postnatal management, develop risk stratification algorithms to guide management and standardize laboratory testing to identify high risk pregnancies are needed.
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Affiliation(s)
- Lani Lieberman
- University of Toronto, Toronto, Canada.,University Health Network, Toronto, Canada
| | - Andreas Greinacher
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Michael F Murphy
- National Health Service (NHS) Blood and Transplant and the Oxford National Institute for Health Research (NIHR) Biomedical Research Centre, Oxford University Hospitals and University of Oxford, Oxford, United Kingdom
| | | | | | | | - Mette Kjaer
- Finnmark Hospital Trust, Hammerfest, Norway.,University Hospital of North Norway, Tromsø, Norway
| | - Jens Kjeldsen-Kragh
- University Hospital of North Norway, Tromsø, Norway.,University and Regional Laboratories Region Skåne, Lund, Sweden
| | - Gerald Bertrand
- Blood Center of Brittany - EFS L'Établissement Français du Sang, Rennes, France
| | - Dick Oepkes
- Leiden University Medical Center, Leiden, the Netherlands
| | - Jillian M Baker
- Hospital for Sick Children and St. Michael's Hospital, Toronto, Canada
| | - Heather Hume
- CHU Sainte-Justine, Université de Montréal, Montréal, Canada
| | | | - Cécile Kaplan
- Retired and formerly Institut National de la Transfusion Sanguine, Paris, France
| | - Donald M Arnold
- McMaster Centre for Transfusion Research, McMaster University and Canadian Blood Services, Hamilton, Canada
| | - Shoma Baidya
- Australian Red Cross Blood Service, Brisbane, Australia
| | - Greg Ryan
- University of Toronto, Toronto, Canada.,Mount Sinai Hospital, Toronto, Canada
| | | | | | - Nadine Shehata
- University of Toronto, Toronto, Canada.,Mount Sinai Hospital, Toronto, Canada.,Canadian Blood Services, Toronto, Canada
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8
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Bertrand G, Blouin L, Boehlen F, Levine E, Minon JM, Winer N. Management of neonatal thrombocytopenia in a context of maternal antiplatelet alloimmunization: Expert opinion of the French-speaking working group. Arch Pediatr 2019; 26:191-197. [PMID: 30827773 DOI: 10.1016/j.arcped.2019.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/13/2018] [Accepted: 02/03/2019] [Indexed: 01/07/2023]
Abstract
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, seen in 1/800-1000 neonates. FNAIT is the most common cause of early-onset isolated severe neonatal thrombocytopenia in maternity wards. The most feared complication of this disorder is intracranial hemorrhage, leading to death or neurological sequelae. There is no systematic screening of at-risk pregnancies and FNAIT is often discovered when fetal or neonatal bleeding is observed. A working group on fetomaternal platelet alloimmunization was created in 2017, under the auspices on the French Group of Thrombosis and Hemostasis (GFHT). The first objective of this group was to survey clinical practices for treatment of thrombocytopenic neonates in a context of suspected or confirmed FNAIT.
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Affiliation(s)
- G Bertrand
- laboratoire HLA-HPA, Établissement français du sang (EFS) Bretagne, rue Pierre-Jean-Gineste, BP 91614, 35016 Rennes cedex, France.
| | - L Blouin
- Laboratoire d'immunologie et immunogénétique, EFS Nouvelle Aquitaine, CHU de Bordeaux, place Amélie-Léon, 33076 Bordeaux cedex, France
| | - F Boehlen
- Service d'angiologie et d'hémostase, hôpitaux universitaires de Genève, 4, rue Gabrielle-Perret-Gentil, 1211 Genève 14, Switzerland
| | - E Levine
- Service de néonatologie soins intensifs, hôpital universitaire de Rennes, 16, boulevard de Bulgarie, 35000 Rennes, France
| | - J-M Minon
- Unité d'hémostase et de transfusion, département de médecine de laboratoire, centre hospitalier régional de la Citadelle, boulevard du XXII(e)-de-Ligne, 4000 Liège, Belgium
| | - N Winer
- INRA, UMR 1280, département de gynécologie et d'obstétrique, physiologie des adaptations nutritionnelles, hôpital universitaire de Nantes, 38, boulevard Jean-Monnet, 44093 Nantes cedex 1, France
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9
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Hinson AP, Saxonhouse M. Neonatal thrombosis after antenatal treatment of neonatal alloimmune thrombocytopenia with intravenous immunoglobulin. J Clin Neonatol 2019. [DOI: 10.4103/jcn.jcn_44_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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10
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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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11
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Zhi H, Ahlen MT, Thinn AMM, Weiler H, Curtis BR, Skogen B, Zhu J, Newman PJ. High-resolution mapping of the polyclonal immune response to the human platelet alloantigen HPA-1a (Pl A1). Blood Adv 2018; 2:3001-3011. [PMID: 30413435 PMCID: PMC6234362 DOI: 10.1182/bloodadvances.2018023341] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
Antibodies to platelet-specific antigens are responsible for 2 clinically important bleeding disorders: posttransfusion purpura and fetal/neonatal alloimmune thrombocytopenia (FNAIT). The human platelet-specific alloantigen 1a/1b (HPA-1a/1b; also known as PlA1/A2) alloantigen system of human platelet membrane glycoprotein (GP) IIIa is controlled by a Leu33Pro polymorphism and is responsible for ∼80% of the cases of FNAIT. Local residues surrounding polymorphic residue 33 are suspected to have a profound effect on alloantibody binding and subsequent downstream effector events. To define the molecular requirements for HPA-1a alloantibody binding, we generated transgenic mice that expressed murine GPIIIa (muGPIIIa) isoforms harboring select humanized residues within the plexin-semaphorin-integrin (PSI) and epidermal growth factor 1 (EGF1) domains and examined their ability to support the binding of a series of monoclonal and polyclonal HPA-1a-specific antibodies. Humanizing the PSI domain of muGPIIIa was sufficient to recreate the HPA-1a epitope recognized by some HPA-1a-specific antibodies; however, humanizing distinct amino acids within the linearly distant but conformationally close EGF1 domain was required to enable binding of others. These results reveal the previously unsuspected complex heterogeneity of the polyclonal alloimmune response to this clinically important human platelet alloantigen system. High-resolution mapping of this alloimmune response may improve diagnosis of FNAIT and should facilitate the rational design and selection of contemplated prophylactic and therapeutic anti-HPA-1a reagents.
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Affiliation(s)
- Huiying Zhi
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
| | - Maria Therese Ahlen
- Immunology Research Group, Department of Medical Biology, The Arctic University of Norway, Tromsø, Norway
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Aye Myat Myat Thinn
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
- Department of Biochemistry
| | - Hartmut Weiler
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
| | - Brian R Curtis
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
| | - Bjørn Skogen
- Immunology Research Group, Department of Medical Biology, The Arctic University of Norway, Tromsø, Norway
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Jieqing Zhu
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
- Department of Biochemistry
| | - Peter J Newman
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
- Department of Pharmacology, and
- Department of Cell Biology, Medical College of Wisconsin, Milwaukee, WI
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12
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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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13
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Winkelhorst D, Oepkes D, Lopriore E. Fetal and neonatal alloimmune thrombocytopenia: evidence based antenatal and postnatal management strategies. Expert Rev Hematol 2017. [PMID: 28644735 DOI: 10.1080/17474086.2017.1346471] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a relatively rare but potentially lethal disease, leading to severe bleeding complications in 1 in 11.000 newborns. It is the leading cause of thrombocytopenia in healthy term-born neonates. Areas covered: This review summarizes the antenatal as well as postnatal treatment, thus creating a complete overview of all possible management strategies for FNAIT. Expert commentary: The optimal antenatal therapy in order to prevent bleeding complications in pregnancies complicated by FNAIT is non-invasive treatment with weekly intravenous immunoglobulin (IVIG). Based on risk stratification, weekly doses of IVIG of 0.5 or 1.0g/kg should be administered started early in the second in high risk cases or at the end of the second trimester in low risk cases. The optimal postnatal treatment depends on the platelet count and the clinical condition of the newborn. Prompt administration of compatible platelet transfusion is the first treatment of choice in case of severe thrombocytopenia or active bleeding. In case matched platelets are not directly available, random platelets can also be administered initially to gain time until matched platelets are available. In case of persistent thrombocytopenia despite transfusions, IVIG 1.0-2.0g/kg can be administered.
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Affiliation(s)
- Dian Winkelhorst
- a Division of Fetal Therapy, Department of Obstetrics , Leiden University Medical Center , Leiden , The Netherlands.,b Department Immunohematology Experimental , Sanquin , Amsterdam , The Netherlands
| | - Dick Oepkes
- a Division of Fetal Therapy, Department of Obstetrics , Leiden University Medical Center , Leiden , The Netherlands
| | - Enrico Lopriore
- c Division of Neonatology, Department of Pediatrics , Leiden University Medical Center , Leiden , The Netherlands
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15
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Tiller H, Husebekk A, Ahlen MT, Stuge TB, Skogen B. Current perspectives on fetal and neonatal alloimmune thrombocytopenia - increasing clinical concerns and new treatment opportunities. Int J Womens Health 2017; 9:223-234. [PMID: 28458583 PMCID: PMC5402885 DOI: 10.2147/ijwh.s90753] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Differences in platelet type between the fetus and the mother can lead to maternal immunization and destruction of the fetal platelets, a condition named fetal and neonatal alloimmune thrombocytopenia (FNAIT). FNAIT is reported to occur in ~1 per 1,000 live born neonates. The major risk is intracranial hemorrhage in the fetus or newborn, which is associated with severe neurological complications or death. Since no countries have yet implemented a screening program to detect pregnancies at risk, the diagnosis is typically established after the birth of a child with symptoms. Reports on broader clinical impact have increased clinical concern and awareness. Along with new treatment options for FNAIT, the debate around antenatal screening to detect pregnancies at risk of FNAIT has been revitalized.
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Affiliation(s)
- Heidi Tiller
- Immunology Research Group, Faculty of Health Sciences, UiT, The Arctic University of Norway
| | - Anne Husebekk
- Immunology Research Group, Faculty of Health Sciences, UiT, The Arctic University of Norway
| | | | - Tor B Stuge
- Immunology Research Group, Faculty of Health Sciences, UiT, The Arctic University of Norway
| | - Bjørn Skogen
- Department of Laboratory Medicine, Norwegian National Unit for Platelet Immunology, University Hospital of North Norway, Tromsø, Norway
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Sonneveld ME, Natunen S, Sainio S, Koeleman CAM, Holst S, Dekkers G, Koelewijn J, Partanen J, van der Schoot CE, Wuhrer M, Vidarsson G. Glycosylation pattern of anti-platelet IgG is stable during pregnancy and predicts clinical outcome in alloimmune thrombocytopenia. Br J Haematol 2016; 174:310-20. [PMID: 27017954 DOI: 10.1111/bjh.14053] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/26/2016] [Indexed: 12/16/2022]
Abstract
Fetal or neonatal alloimmune thrombocytopenia (FNAIT) is a potentially life-threatening disease where fetal platelets are destroyed by maternal anti-platelet IgG alloantibodies. The clinical outcome varies from asymptomatic, to petechiae or intracranial haemorrhage, but no marker has shown reliable correlation with severity, making screening for FNAIT impractical and highly inefficient. We recently found IgG Fc-glycosylation towards platelet and red blood cell antigens to be skewed towards decreased fucosylation, increased galactosylation and sialylation. The lowered core-fucosylation increases the affinity of the pathogenic antibodies to FcγRIIIa and FcγRIIIb, and hence platelet destruction. Here we analysed the N-linked glycans of human platelet antigen (HPA)-1a specific IgG1 with mass spectrometry in large series of FNAIT cases (n = 166) including longitudinal samples (n = 26). Besides a significant decrease in Fc-fucosylation after the first pregnancy (P = 0·0124), Fc-glycosylation levels remained stable during and after pregnancy and in subsequent pregnancies. Multiple logistic regression analysis identified anti-HPA-1a -fucosylation (P = 0·006) combined with galactosylation (P = 0·021) and antibody level (P = 0·038) correlated with bleeding severity, making these parameters a feasible marker in screening for severe cases of FNAIT.
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Affiliation(s)
- Myrthe E Sonneveld
- Department of Experimental Immunohaematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Suvi Natunen
- Finnish Red Cross Blood Service, Helsinki, Finland
| | | | - Carolien A M Koeleman
- Centre for Proteomics and Metabolomics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Stephanie Holst
- Centre for Proteomics and Metabolomics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Gillian Dekkers
- Department of Experimental Immunohaematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Joke Koelewijn
- Department of Experimental Immunohaematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | | | - C Ellen van der Schoot
- Department of Experimental Immunohaematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Manfred Wuhrer
- Centre for Proteomics and Metabolomics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Gestur Vidarsson
- Department of Experimental Immunohaematology, Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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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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Bouwmans EE, Smethurst PA, Garner SF, Ouwehand WH, Morley SL. Expression of a single-chain human leukocyte antigen-DRA/DRB3*01:01 molecule and differential binding of a monoclonal antibody in the presence of specifically bound human platelet antigen-1a peptide. Transfusion 2013; 54:1478-85. [DOI: 10.1111/trf.12502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 10/06/2013] [Accepted: 10/10/2013] [Indexed: 11/26/2022]
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Inhibition of HPA-1a alloantibody-mediated platelet destruction by a deglycosylated anti-HPA-1a monoclonal antibody in mice: toward targeted treatment of fetal-alloimmune thrombocytopenia. Blood 2013; 122:321-7. [PMID: 23645838 DOI: 10.1182/blood-2012-11-468561] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is often caused by maternal alloantibodies against the human platelet antigen (HPA)-1a, which opsonizes fetal platelets (PLTs). Subsequent PLT destruction is mediated via the Fc part of the alloantibodies. The monoclonal antibody (mAb) SZ21 binds to the HPA-1a epitope and inhibits the binding of maternal alloantibodies. However, it also promotes complement activation and phagocytosis. Deglycosylation of antibodies abrogates the Fc-related effector functions. We modified the N-glycan of SZ21 by endoglycosidase F. The in vivo transplacental transport of N-glycan-modified (NGM)-SZ21 was not impaired. When injected into pregnant mice, both native-SZ21 and NGM-SZ21 were transported equally into fetal circulation (8.9% vs 8.7%, respectively, P = .58). Neither the binding properties of NGM-SZ21 to HPA-1a in surface plasmon resonance, nor the inhibition of anti-HPA-1a-induced PLT phagocytosis, were affected by N-glycan modification. NGM-SZ21 prevented PLT destruction induced by maternal anti-HPA-1a antibodies in vivo in a mouse model (PLT clearance after 5 hours; 18% vs 62%, in the presence or absence of NGM-SZ21, respectively, P = .013). Deglycosylation of SZ21 abrogates Fc-effector functions without interfering with placental transport or the ability to block anti-HPA-1a binding. Humanized, deglycosylated anti-HPA-1a mAbs may represent a novel treatment strategy to prevent anti-HPA-1a-mediated PLT destruction in FNAIT.
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Sainio S, Javela K, Tuimala J, Koskinen S. Usefulness of maternal anti-HPA-1a antibody quantitation in predicting severity of foetomaternal alloimmune thrombocytopenia. Transfus Med 2013; 23:114-20. [DOI: 10.1111/tme.12018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/18/2012] [Accepted: 01/29/2013] [Indexed: 11/29/2022]
Affiliation(s)
- S. Sainio
- Finnish Red Cross Blood Service; Platelet Immunology laboratory; Helsinki; Finland
| | - K. Javela
- Finnish Red Cross Blood Service; Platelet Immunology laboratory; Helsinki; Finland
| | - J. Tuimala
- Finnish Red Cross Blood Service; Platelet Immunology laboratory; Helsinki; Finland
| | - S. Koskinen
- Finnish Red Cross Blood Service; Platelet Immunology laboratory; Helsinki; Finland
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Husebekk A, El Ekiaby M, Gorgy G, Killie MK, Uhlin-Hansen C, Salma W, Navarrete C, El Afandi M, Skogen B, Ahlen MT. Foetal/neonatal alloimmune thrombocytopenia in Egypt; human platelet antigen genotype frequencies and antibody detection and follow-up in pregnancies. Transfus Apher Sci 2012; 47:277-82. [PMID: 22640833 DOI: 10.1016/j.transci.2012.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/17/2012] [Accepted: 04/30/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVES Foetal and neonatal alloimmune thrombocytopenia (FNAIT) is studied mainly in Caucasian populations. Severe thrombocytopenia (<50×10(9)/L) gives risk of haemorrhage and the most feared complication is intracranial haemorrhage (ICH). In Caucasian populations anti-human platelet antigen (HPA)-1a antibodies are the cause of FNAIT in >80% of the cases. The aims of this project were to study the gene frequencies of HPA-1-5 and 15 alleles in an Egyptian population (Arabic), and to determine the frequency of HPA-1a and -5b immunisations in a cohort of Egyptian pregnant women. MATERIALS AND METHODS Altogether 6974 pregnant women were included in the study. Genotyping was performed by polymerase chain reaction and antibodies were detected by flow cytometry and enzyme-linked immunosorbent assay. HPA-1-5 and 15 alleles were studied in 367 individuals. RESULTS The HPA genotypes differed from genotypes published from different Caucasian and Chinese (Han) populations in HPA-1, -2, -3, and -5 systems with significant higher frequency of HPA-1b, -2b and -5b. The rate of HPA-1a alloimmunisation was found comparable to Caucasian populations. Severe thrombocytopenia was found in two newborns. No bleeding complication was reported. Anti-HPA-5b antibodies were detected in 4.4% of the pregnant women. Clinical consequences of these antibodies were not studied. CONCLUSION The HPA-1bb and -5bb genotypes are more frequent in the Egyptian Arabic population studied compared to Caucasian populations. FNAIT due to anti-HPA-1a and -5b antibodies must be suspected in cases of neonatal thrombocytopenia. Further large prospective studies are needed to increase the knowledge of clinical complications related to HPA alloantibodies in populations with different genetic backgrounds.
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Affiliation(s)
- A Husebekk
- Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
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22
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Allen DL, Abrahamsson S, Murphy MF, Roberts DJ. Human platelet antigen 1a epitopes are dependent on the cation-regulated conformation of integrin α(IIb)β(3) (GPIIb/IIIa). J Immunol Methods 2011; 375:166-75. [PMID: 22036924 DOI: 10.1016/j.jim.2011.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 09/18/2011] [Accepted: 10/07/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND The HPA-1a (Leu(33)) polymorphism of platelet integrin αIIbβ3 is the target of alloantibodies in 70-80% cases of neonatal alloimmune thrombocytopenia (NAIT) in Caucasians and reliable detection of these antibodies is essential for appropriate clinical management. However, the ability to detect such antibodies is highly variable between laboratories and, in a number of clinical cases where there is a HPA-1 genotype mismatch between mother and neonate, HPA-1a antibodies are undetectable. Furthermore, some studies have not shown a consistent relationship between maternal anti-HPA-1a level and neonatal platelet count. Since the integrity and conformation of the αIIbβ3 complex are dependent on divalent cations, we investigated whether HPA-1a epitope integrity and/or conformation might be affected by the presence of the cation chelator EDTA in patient samples or in assay buffers, thus providing a possible explanation for the variable sensitivity of current assays. PRINCIPLE FINDINGS Exposure of the αIIbβ3 complex to EDTA resulted in reduced reactivity of three anti-HPA-1a mAbs (B2, 19-7 and 23-15). More significantly, cation chelation adversely affected detection of polyclonal anti-HPA-1a, not only in the platelet immunofluorescence assay, where alloantibody binding was reduced compared to control platelets (mean MFI reduction 44.5%, range 17.3-69.7%, n=4), but also in the commonly used monoclonal antibody specific immobilisation of platelet antigens assay (MAIPA) where both alloantibody and monoclonal capture antibody binding were reduced (mean OD reduction 82.8%, range 68.3-96.6%, n=9). CONCLUSIONS These data show that HPA-1a antibodies recognise epitopes on αIIbβ3 that are sensitive to EDTA treatment and that cation chelation grossly reduces the sensitivity of the MAIPA assay by diminishing not only HPA-1a alloantibody binding but also 'capture' monoclonal antibody binding. These findings may, in part, explain the current variability in antibody measurement and will guide the development of more sensitive tests for anti-integrin antibodies in NAIT and other conditions.
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Affiliation(s)
- David L Allen
- NHS Blood and Transplant, John Radcliffe Hospital, Oxford, UK.
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Abstract
Although neonatal thrombocytopenia (platelet count < 150×10(9) /l) is a common finding in hospital practice, a careful clinical history and examination of the blood film is often sufficient to establish the diagnosis and guide management without the need for further investigations. In preterm neonates, early-onset thrombocytopenia (<72h) is usually secondary to antenatal causes, has a characteristic pattern and resolves without complications or the need for treatment. By contrast, late-onset thrombocytopenia in preterm neonates (>72h) is nearly always due to post-natally acquired bacterial infection and/or necrotizing enterocolitis, which rapidly leads to severe thrombocytopenia (platelet count<50×10(9) /l). Thrombocytopenia is much less common in term neonates and the most important cause is neonatal alloimmune thrombocytopenia (NAIT), which confers a high risk of perinatal intracranial haemorrhage and long-term neurological disability. Prompt diagnosis and transfusion of human platelet antigen-compatible platelets is key to the successful management of NAIT. Recent studies suggest that more than half of neonates with severe thrombocytopenia receive platelet transfusion(s) based on consensus national or local guidelines despite little evidence of benefit. The most pressing problem in management of neonatal thrombocytopenia is identification of safe, effective platelet transfusion therapy and controlled trials are urgently needed.
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Affiliation(s)
- Subarna Chakravorty
- Centre for Haematology, Imperial College London, London Department of Paediatrics, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
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Kamphuis MM, Oepkes D. Fetal and neonatal alloimmune thrombocytopenia: prenatal interventions. Prenat Diagn 2011; 31:712-9. [DOI: 10.1002/pd.2779] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/20/2011] [Accepted: 04/21/2011] [Indexed: 11/05/2022]
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Skogen B, Killie MK, Kjeldsen-Kragh J, Ahlen MT, Tiller H, Stuge TB, Husebekk A. Reconsidering fetal and neonatal alloimmune thrombocytopenia with a focus on screening and prevention. Expert Rev Hematol 2011; 3:559-66. [PMID: 21083473 DOI: 10.1586/ehm.10.49] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Uncertainty regarding the pathophysiology of fetal and neonatal alloimmune thrombocytopenia (FNAIT) has hampered the decision regarding how to identify, follow-up and treat the women and children with this potentially serious condition. Since knowledge of the condition is derived mainly from retrospective studies, understanding of the natural history of this condition remains incomplete. General screening programs for FNAIT have still not been introduced, mainly because of a lack of reliable risk factors and effective treatment. Now, several prospective screening studies involving up to 100,000 pregnant women have been published and the results have changed the understanding of the pathophysiology of FNAIT and, thereby, the approach toward diagnostics, prevention and treatment in a more appropriate way.
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Affiliation(s)
- Bjørn Skogen
- Laboratory Medicine, University Hospital of North Norway, N-9038 Tromsø, Norway.
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Rayment R, Brunskill SJ, Soothill PW, Roberts DJ, Bussel JB, Murphy MF. Antenatal interventions for fetomaternal alloimmune thrombocytopenia. Cochrane Database Syst Rev 2011:CD004226. [PMID: 21563140 DOI: 10.1002/14651858.cd004226.pub3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Fetomaternal alloimmune thrombocytopenia results from the formation of antibodies by the mother which are directed against a fetal platelet alloantigen inherited from the father. The resulting fetal thrombocytopenia (reduced platelet numbers) may cause bleeding, particularly into the brain, before or shortly after birth. Antenatal treatment of fetomaternal alloimmune thrombocytopenia includes the administration of intravenous immunoglobulin (IVIG) and/or corticosteroids to the mother to prevent severe fetal thrombocytopenia. IVIG and corticosteroids both have short-term and possibly long-term side effects. IVIG is also costly and optimal regimens need to be identified. OBJECTIVES To determine the optimal antenatal treatment of fetomaternal alloimmune thrombocytopenia to prevent fetal and neonatal haemorrhage and death. SEARCH STRATEGY We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 February 2011) and bibliographies of relevant publications and review articles. SELECTION CRITERIA Randomised controlled studies comparing any intervention with no treatment, or comparing any two interventions. DATA COLLECTION AND ANALYSIS Two review authors independently assessed eligibility, trial quality and extracted data. MAIN RESULTS We included four trials involving 206 people. One trial involving 39 people compared a corticosteroid (prednisone) versus IVIG alone. In this trial, where analysable data were available, there was no statistically significant differences between the treatment arms for predefined outcomes. Three trials involving 167 people compared IVIG plus a corticosteroid (prednisone in two trials and dexamethasone in one trial) versus IVIG alone. In these trials there was no statistically significant difference in the findings between the treatment arms for predefined outcomes (intracranial haemorrhage; platelet count at birth and preterm birth). Lack of complete data sets and important differences in interventions precluded the pooling of data from these trials. AUTHORS' CONCLUSIONS The optimal management of fetomaternal alloimmune thrombocytopenia remains unclear. Lack of complete data sets for two trials and differences in interventions precluded the pooling of data from these trials which may have enabled a more developed analysis of the trial findings. Further trials would be required to determine optimal treatment (the specific medication and its dose and schedule). Such studies should include long-term follow up of all children and mothers.
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Affiliation(s)
- Rachel Rayment
- Arthur Bloom Haemophilia Centre, University Hospital of Wales, Cardiff and Vale NHS Trust, Heath Park, Cardiff, UK, CF14 4XW
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McQuilten ZK, Wood EM, Savoia H, Cole S. A review of pathophysiology and current treatment for neonatal alloimmune thrombocytopenia (NAIT) and introducing the Australian NAIT registry. Aust N Z J Obstet Gynaecol 2011; 51:191-8. [PMID: 21631435 DOI: 10.1111/j.1479-828x.2010.01270.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fetomaternal or neonatal alloimmune thrombocytopenia (NAIT) is a rare but serious condition associated with significant fetal and neonatal morbidity and mortality. The most useful predictor of severe disease is a history of a sibling with an antenatal intracranial haemorrhage. However, NAIT can occur during the first pregnancy and may not be diagnosed until the neonatal period. Antenatal treatment options include maternal intravenous immunoglobulin (IVIG) and corticosteroid treatment, fetal blood sampling (FBS) and intrauterine platelet transfusion (IUT) and early delivery. FBS (with or without IUT) can be used to direct and monitor response to therapy, and to inform mode and timing of delivery. However, this procedure is associated with significant risks, including fetal death, and is generally now reserved for high-risk pregnancies. This review highlights the current understanding of the epidemiology and pathophysiology of NAIT and summarises current approaches to investigation and management. It also introduces the newly established Australian NAIT registry. Owing to the relative rarity of NAIT, accruing sufficient patient numbers for studies and clinical trials at an institutional level is difficult. This national registry will provide an opportunity to collect valuable information and inform future research on this condition.
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Affiliation(s)
- Zoe K McQuilten
- Transfusion Medicine Services, Australian Red Cross Blood Service, South Melbourne, Victoria 3205, Australia.
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Chong W, Metcalfe P, Mushens R, Lucas G, Ouwehand WH, Navarrete CV. Detection of human platelet antigen-1a alloantibodies in cases of fetomaternal alloimmune thrombocytopenia using recombinant β3 integrin fragments coupled to fluorescently labeled beads. Transfusion 2010; 51:1261-70. [DOI: 10.1111/j.1537-2995.2010.02977.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Killie MK, Salma W, Bertelsen E, Skogen B, Husebekk A. Quantitative MAIPA: Comparison of different MAIPA protocols. Transfus Apher Sci 2010; 43:149-54. [PMID: 20675194 DOI: 10.1016/j.transci.2010.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION In a screening setting, maternal anti-HPA 1a antibody level has been found to be a good prognostic tool to identify newborns at risk for severe NAIT. AIM Identify the optimal MAIPA protocol for quantitation of anti-HPA 1a antibodies. MATERIALS AND METHODS Plasma were analysed for anti-HPA 1a antibodies using different monoclonal antibodies, lyophilized or fresh platelets and MAIPA protocols. RESULTS The anti-HPA 1a antibody level varied significantly when different monoclonal antibodies were used. However, there was a strong correlation between maternal anti-HPA 1a antibody level and platelet count in the newborn. The sensitivity of the assay depended on the adopted MAIPA protocol. CONCLUSION Consistent tests results are of importance for the clinical impact of the test.
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Affiliation(s)
- Mette Kjær Killie
- Department of Immunology and Transfusion Medicine, University Hospital of North Norway, 9038 Tromsø, Norway.
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30
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Kamphuis MM, Paridaans N, Porcelijn L, De Haas M, van der Schoot CE, Brand A, Bonsel GJ, Oepkes D. Screening in pregnancy for fetal or neonatal alloimmune thrombocytopenia: systematic review. BJOG 2010; 117:1335-43. [DOI: 10.1111/j.1471-0528.2010.02657.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
PURPOSE OF REVIEW The purpose of the review is to argue for and against introduction of HPA-1 typing of all pregnant women to reduce morbidity and mortality caused by foetal/neonatal alloimmune thrombocytopenia (FNAIT). RECENT FINDING Several groups have done HPA-1 typing in cohorts of pregnant women. Results from a Norwegian study (>100,000 pregnancies) indicate that screening combined with simple intervention decreases morbidity and mortality due to FNAIT and is cost effective in Norway. Results from this study and several other studies show that there is correlation between the level of anti-HPA-1a antibodies in the mother and the severity of thrombocytopenia in the newborn. An important finding is that about 75% of women with antibodies are immunized in connection with delivery. Only 25% of the women are immunized during pregnancy. SUMMARY Screening for FNAIT does not fully meet the criteria presented by the WHO. Nevertheless, the results of the Norwegian study strongly indicate that morbidity and mortality related to FNAIT can be reduced. If the recent attempts to make a vaccine aimed at prevention of immunization and/or tolerizing peptides or neutralizing antibodies for already immunized women are shown to be successful, screening must be implemented.
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Skogen B, Husebekk A, Killie MK, Kjeldsen-Kragh J. Neonatal alloimmune thrombocytopenia is not what it was: a lesson learned from a large prospective screening and intervention program. Scand J Immunol 2009; 70:531-4. [PMID: 19906194 DOI: 10.1111/j.1365-3083.2009.02339.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Controversies regarding the pathophysiology of neonatal alloimmune thrombocytopenia (NAIT) has hampered the development of consensus about how to identify, follow up and treat the women and children with this serious complication. One reason for this is that knowledge about the condition derived from previous retrospective studies do not necessarily conform with data derived from prospective investigations. The main obstacle to introduction of general screening programs to identify the pregnancies to treat, have been lack of reliable risk factors, and an effective treatment. Now, several recent prospective screening programs including up to 100,000 pregnant women has changed the understanding of the NAIT-pathology, and has shown that we are close to answering these critical questions.
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Affiliation(s)
- B Skogen
- Immunology and Transfusion Medicine, University Hospital of North Norway, Tromsø, Norway.
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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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Socher I, Andrei-Selmer C, Bein G, Kroll H, Santoso S. Low-avidity HPA-1a alloantibodies in severe neonatal alloimmune thrombocytopenia are detectable with surface plasmon resonance technology. Transfusion 2009; 49:943-52. [PMID: 19175553 DOI: 10.1111/j.1537-2995.2008.02065.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is mostly caused by maternal alloantibodies directed against the human platelet alloantigen (HPA)-1a. Currently, the serologic diagnosis of FNAIT is based on the characterization of the HPA alloantibodies in monoclonal antibody-based antigen-capture assays (e.g., MAIPA assay). Accumulated current evidence indicated that such assays may overlook some HPA-1a antibodies. STUDY DESIGN AND METHODS This study employed surface plasmon resonance (SPR) technology using immunoaffinity-purified glycoprotein IIb/IIIa isoforms immobilized on biosensor chips to study the binding kinetics of HPA-1a alloantibodies from different FNAIT cases in real time. RESULTS Analysis of HPA-1a alloantibodies from FNAIT cases (n = 9) in SPR showed a moderate relative response (22.2-69.7 resonance units [RU]) and slow antibody dissociation. After the dissociation phase, varying amounts of bound antibodies (41%-79%) remained on the chip. In contrast in HPA-1a alloantibodies from a patient suffering from posttransfusion purpura, a high relative response (approximately 490 RU) was observed at the end of the association phase and no dissociation of antibody binding was detectable. Of particular relevance, by the use of this SPR technique, HPA-1a alloantibodies were detected in two severe FNAIT cases that had determined as false negative by MAIPA assay. In SPR, these HPA-1a alloantibodies showed low-avidity nature characterized by gradual dissociation of antibody during the association phase and complete detachment of antibody binding after the dissociation phase. This high "off-rate" character of low-avidity HPA-1a alloantibodies indicates that such antibody binding is easily detachable by the extensive washing procedure of the MAIPA. CONCLUSIONS Our results demonstrated that the SPR method can facilitate the diagnosis of clinically relevant low-avidity HPA-1a antibodies.
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Affiliation(s)
- Ines Socher
- Institute for Clinical Immunology and Transfusion Medicine, Giessen, Germany
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35
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Bessos H, Killie MK, Matviyenko M, Husebekk A, Urbaniak SJ. Direct comparison between two quantitative assays in the measurement of maternal anti-HPA-1a antibody in neonatal alloimmune thrombocytopenia (NAIT). Transfus Apher Sci 2008; 39:221-7. [DOI: 10.1016/j.transci.2008.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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van Gils JM, Stutterheim J, van Duijn TJ, Zwaginga JJ, Porcelijn L, de Haas M, Hordijk PL. HPA-1a alloantibodies reduce endothelial cell spreading and monolayer integrity. Mol Immunol 2008; 46:406-15. [PMID: 19038456 DOI: 10.1016/j.molimm.2008.10.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/13/2008] [Accepted: 10/14/2008] [Indexed: 12/01/2022]
Abstract
Maternal human platelet antigen (HPA)-1a alloantibodies causing neonatal alloimmune thrombocytopenia can bind also to endothelium, via the beta3-integrin (CD61). The aim of this study was to investigate the effect of HPA-1a Abs on endothelial cell function, with emphasis on monolayer integrity. We used a CD61 mAb as a model for the HPA-1a alloantibodies and confirmed the results with purified IgG fractions from HPA-1a alloimmunized women. The effect of these antibodies was examined by monitoring the adhesion, spreading, and monolayer integrity of primary HUVECs with conventional adhesion assays as well as electrical cell-substrate impedance sensing. We found that both the mAb CD61 and the HPA-1a antibodies caused a significant reduction in HUVEC spreading. Moreover, addition of the mAb CD61 and the HPA-1a antibodies prior to or following formation of a stable endothelial monolayer negatively affected endothelial monolayer integrity, which was accompanied by a redistribution of junctional proteins. Our data suggest that HPA-1a alloantibodies have a direct effect on endothelial cell spreading and monolayer integrity, which could contribute to the increased bleeding tendency in children with neonatal alloimmune thrombocytopenia.
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Affiliation(s)
- Janine M van Gils
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Bessos H, Matviyenko M, Brown P, Husebekk A, Killie M, Seghatchian J, Santoso S, Urbaniak S. What’s happening – Probing of HPA-1a antigen–antibody interaction by surface plasmon resonance technology. Transfus Apher Sci 2008; 39:179-82. [DOI: 10.1016/j.transci.2008.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ghevaert C, Wilcox DA, Fang J, Armour KL, Clark MR, Ouwehand WH, Williamson LM. Developing recombinant HPA-1a-specific antibodies with abrogated Fcgamma receptor binding for the treatment of fetomaternal alloimmune thrombocytopenia. J Clin Invest 2008; 118:2929-38. [PMID: 18654666 DOI: 10.1172/jci34708] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 05/21/2008] [Indexed: 11/17/2022] Open
Abstract
Fetomaternal alloimmune thrombocytopenia (FMAIT) is caused by maternal generation of antibodies specific for paternal platelet antigens and can lead to fetal intracranial hemorrhage. A SNP in the gene encoding integrin beta3 causes a clinically important maternal-paternal antigenic difference; Leu33 generates the human platelet antigen 1a (HPA-1a), whereas Pro33 generates HPA-1b. As a potential treatment to prevent fetal intracranial hemorrhage in HPA-1a alloimmunized pregnancies, we generated an antibody that blocks the binding of maternal HPA-1a-specific antibodies to fetal HPA-1a1b platelets by combining a high-affinity human HPA-1a-specific scFv (B2) with an IgG1 constant region modified to minimize Fcgamma receptor-dependent platelet destruction (G1Deltanab). B2G1Deltanab saturated HPA-1a+ platelets and substantially inhibited binding of clinical HPA-1a-specific sera to HPA-1a+ platelets. The response of monocytes to B2G1Deltanab-sensitized platelets was substantially less than their response to unmodified B2G1, as measured by chemiluminescence. In addition, B2G1Deltanab inhibited chemiluminescence induced by B2G1 and HPA-1a-specific sera. In a chimeric mouse model, B2G1 and polyclonal Ig preparations from clinical HPA-1a-specific sera reduced circulating HPA-1a+ platelets, concomitant with transient thrombocytopenia. As the Deltanab constant region is uninformative in mice, F(ab')2 B2G1 was used as a proof of principle blocking antibody and prevented the in vivo platelet destruction seen with B2G1 and polyclonal HPA-1a-specific antibodies. These results provide rationale for human clinical studies.
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Affiliation(s)
- Cedric Ghevaert
- NHS Blood and Transplant, Department of Haematology, University of Cambridge, Cambridge, United Kingdom.
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Abstract
Thrombocytopenia is one of the commonest haematological problems in neonates, affecting at least 25% of all admissions to neonatal intensive care units (NICUs) [Murray NA, Howarth LJ, McCloy MP et al. Platelet transfusion in the management of severe thrombocytopenia in neonatal intensive care unit patients. Transfus Med 2002;12:35-41; Garcia MG, Duenas E, Sola MC et al. Epidemiologic and outcome studies of patients who received platelet transfusions in the neonatal intensive care unit. J Perinatol 2001;21:415-20; Del Vecchio A, Sola MC, Theriaque DW et al. Platelet transfusions in the neonatal intensive care unit: factors predicting which patients will require multiple transfusions. Transfusion 2001;41:803-8]. Although a long list of disorders associated with neonatal thrombocytopenia can be found in many textbooks, newer classifications based on the timing of onset of thrombocytopenia (early vs. late) are more useful for planning diagnostic investigations and day-to-day management. The mainstay of treatment of neonatal thrombocytopenia remains platelet transfusion although it is important to note that no studies have yet shown clinical benefit of platelet transfusion in this setting. Indeed some reports even suggest that there may be significant adverse effects of platelet transfusion in neonates, including increased mortality, and that the effects of transfusion may differ in different groups of neonates with similar degrees of thrombocytopenia [Bonifacio L, Petrova A, Nanjundaswamy S, Mehta R. Thrombocytopenia related neonatal outcome in preterms. Indian J Pediatr 2007;74:269-74; Kenton AB, Hegemier S, Smith EO et al. Platelet transfusions in infants with necrotizing enterocolitis do not lower mortality but may increase morbidity. J Perinatol 2005;25:173-7]. There is also considerable variation in transfusion practice between different countries and between different neonatal units. Here we review recent progress in understanding the prevalence, causes and pathogenesis of thrombocytopenia in the newborn, the clinical consequences of thrombocytopenia and developments in neonatal platelet transfusion.
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Affiliation(s)
- Irene Roberts
- Paediatric Haematology, Imperial College, London, UK.
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Smith GA, Rankin A, Riddle C, Cheetham-Wilkinson C, Ranasinghe E, Ouwehand WH, Watkins NA. Severe fetomaternal alloimmune thrombocytopenia due to anti-human platelet antigen (HPA)-1a in a mother with a rare and silenced ITGB3*0101 (GPIIIa) allele. Vox Sang 2007; 93:325-30. [DOI: 10.1111/j.1423-0410.2007.00968.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Rayment R, Brunskill SJ, Stanworth S, Soothill PW, Roberts DJ, Murphy MF. Antenatal interventions for fetomaternal alloimmune thrombocytopenia. Cochrane Database Syst Rev 2005:CD004226. [PMID: 15674934 DOI: 10.1002/14651858.cd004226.pub2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Fetomaternal alloimmune thrombocytopenia occurs when the mother produces antibodies against a platelet alloantigen that the fetus has inherited from the father. A consequence of this can be a reduced number of platelets (thrombocytopenia) in the fetus, which can result in bleeding whilst in the womb or shortly after birth. In severe cases this bleeding may lead to long-lasting disability or death. Antenatal management of fetomaternal alloimmune thrombocytopenia centres on preventing severe thrombocytopenia in the fetus. Available management options include administration of intravenous immunoglobulins or corticosteroids to the mother or intrauterine transfusion of antigen compatible platelets to the fetus. All options are costly and need to be assessed in terms of potential risk and benefit to both the mother and an individual fetus. OBJECTIVES To determine the optimal antenatal treatment of fetomaternal alloimmune thrombocytopenia to prevent fetal and neonatal haemorrhage and death. SEARCH STRATEGY We searched the Cochrane Pregnancy and Childbirth Group trials register (February 2004), EMBASE (1980 to February 2004) and bibliographies of relevant publications and review articles. SELECTION CRITERIA Randomised controlled studies comparing any intervention, including corticosteroids with no treatment, or comparing any two interventions. DATA COLLECTION AND ANALYSIS Two reviewers independently assessed eligibility, trial quality and extracted data. MAIN RESULTS One study met the inclusion criteria (54 pregnant women). This trial compared intravenous immunoglobulins plus corticosteroid (dexamethasone) with intravenous immunoglobulins alone. No significant differences were reported between the treatment and control groups, in any outcome measured: mean platelet count at birth (weighted mean difference (WMD) 14.10 x 10 9/l, 95% confidence interval (CI) -30.26 to 58.46), mean gestational age at birth (WMD -0.50 weeks, 95% CI -2.69 to 1.69), mean rise in platelet count from first to second fetal blood screen (WMD -3.50 x 10 9/l, 95% CI -24.62 to 17.62) and mean rise in platelet count from birth to first fetal blood screen (WMD 24.40 x 10 9/l (95% CI -14.17 to 62.97)). This trial had adequate methodological quality; however the method used to calculate sample size was inappropriate: therefore the power calculation was not sufficient to determine any significance in differences between the treatment groups. AUTHORS' CONCLUSIONS There are insufficient data from randomised controlled trials to determine the optimal antenatal management of fetomaternal alloimmune thrombocytopenia. Future trials should consider the dose of intravenous immunoglobulins, the timing of initial treatment, monitoring of response to treatment by fetal blood sampling, laboratory measures to define pregnancies with a high risk of intercranial haemorrhage, management of non-responders and long-term follow up of children.
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Affiliation(s)
- R Rayment
- Blood Research Laboratory, National Blood Service, Oxford Centre, John Radcliffe Hospital, Headley Way, Oxford, Oxon, UK, OX3 9BQ.
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