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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: 31] [Impact Index Per Article: 4.4] [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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Curtis BR, McFarland JG. Human platelet antigens - 2013. Vox Sang 2013; 106:93-102. [PMID: 24102564 DOI: 10.1111/vox.12085] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 08/12/2013] [Accepted: 08/21/2013] [Indexed: 01/25/2023]
Abstract
To date, 33 human platelet alloantigens (HPAs) have been identified on six functionally important platelet glycoprotein (GP) complexes and have been implicated in alloimmune platelet disorders including foetal and neonatal alloimmune thrombocytopenia (FNAIT), posttransfusion purpura (PTP) and multitransfusion platelet refractoriness (MPR). The greatest number of recognized HPA (20 of 33) resides on the GPIIb/IIIa complex, which serves as the receptor for ligands important in mediating haemostasis and inflammation. These include HPA-1a, the most commonly implicated HPA in FNAIT and PTP in Caucasian populations. Other platelet GP complexes, GPIb/V/IX, GPIa/IIa and CD109, express the remaining 13 HPAs. Of the recognized HPAs, 12 occur as six serologically and genetically defined biallelic 'systems' where the -a form designates the higher frequency allele and the -b form, the lower. Twenty-one other HPAs are low-frequency or rare antigens for which postulated higher frequency -a alleles have not yet been identified as antibody specificities. In addition to the HPA markers, platelets also express ABO and human leucocyte antigen (HLA) antigens; antibodies directed at the former are occasionally important in FNAIT, and to the latter, in MPR.
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Affiliation(s)
- B R Curtis
- Platelet & Neutrophil Immunology Laboratory, BloodCenter of Wisconsin, Milwaukee, WI, USA
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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: 1.0] [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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Foucras G, Corbière F, Tasca C, Pichereaux C, Caubet C, Trumel C, Lacroux C, Franchi C, Burlet-Schiltz O, Schelcher F. Alloantibodies against MHC class I: a novel mechanism of neonatal pancytopenia linked to vaccination. THE JOURNAL OF IMMUNOLOGY 2011; 187:6564-70. [PMID: 22084436 DOI: 10.4049/jimmunol.1102533] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Fetal/neonatal alloimmune thrombocytopenia is a frequent disease in humans where alloantibodies against platelet Ags lead to platelet destruction and hemorrhage. Although a role in the disease for Abs against MHC has been suspected, this has not been formally demonstrated. Since 2007, a hemorrhagic syndrome due to thrombocytopenia and designated as bovine neonatal pancytopenia (BNP) has been recognized in calves in several European countries. An inactivated antiviral vaccine is strongly suspected to be involved in this syndrome because of its highly frequent use in the dams of affected calves. In this study, we show that BNP is an alloimmune disease, as we reproduced the signs by transferring serum Abs from vaccinated BNP dams into healthy neonatal calves. Ab specificity was strongly associated with the presence of allogeneic MHC class I Abs in the dams. MHC class I staining was also observed on Madin-Darby bovine kidney cells, a cell line related to the one used to produce the vaccine Ag. Our report emphatically demonstrates that alloimmunization against MHC class I is associated with a substantial risk of developing cytopenia-associated syndromes in neonates when a cell line of the same species is used to produce an inactivated vaccine injected into the mother.
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Affiliation(s)
- Gilles Foucras
- Université de Toulouse, Institut National Polytechnique de Toulouse, Ecole Nationale Vétérinaire de Toulouse, F-31076 Toulouse, France.
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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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Bakchoul T, Kubiak S, Krautwurst A, Roderfeld M, Siebert HC, Bein G, Sachs UJ, Santoso S. Low-avidity anti-HPA-1a alloantibodies are capable of antigen-positive platelet destruction in the NOD/SCID mouse model of alloimmune thrombocytopenia. Transfusion 2011; 51:2455-61. [DOI: 10.1111/j.1537-2995.2011.03171.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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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: 1.3] [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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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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