1
|
Geringe α-Thrombin/GPIbα-Interaktion trägt möglicherweise zur Hyperreaktivität der Thrombozyten bei COVID-19-Patienten bei. Hamostaseologie 2023; 43:322-3. [PMID: 37857294 DOI: 10.1055/s-0043-1776437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023] Open
Abstract
Mehrere Studien haben gezeigt, dass Thrombozyten mit dem SARSCoV-2 Coronavirus interagieren können. In der Folge kommt es zum programmierten Zelltod, zur Freisetzung extrazellulärer Vesikel und zu einer erhöhten Thrombozytenreaktivität bei Patienten mit der Coronavirus-Krankheit-2019 (COVID-19) als Reaktion auf niedrige Dosen von α-Thrombin.
Collapse
|
2
|
Kiouptsi K, Jäckel S, Wilms E, Pontarollo G, Winterstein J, Karwot C, Groß K, Jurk K, Reinhardt C. The Commensal Microbiota Enhances ADP-Triggered Integrin α IIbβ 3 Activation and von Willebrand Factor-Mediated Platelet Deposition to Type I Collagen. Int J Mol Sci 2020; 21:ijms21197171. [PMID: 32998468 PMCID: PMC7583822 DOI: 10.3390/ijms21197171] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/21/2020] [Accepted: 09/25/2020] [Indexed: 12/12/2022] Open
Abstract
The commensal microbiota is a recognized enhancer of arterial thrombus growth. While several studies have demonstrated the prothrombotic role of the gut microbiota, the molecular mechanisms promoting arterial thrombus growth are still under debate. Here, we demonstrate that germ-free (GF) mice, which from birth lack colonization with a gut microbiota, show diminished static deposition of washed platelets to type I collagen compared with their conventionally raised (CONV-R) counterparts. Flow cytometry experiments revealed that platelets from GF mice show diminished activation of the integrin αIIbβ3 (glycoprotein IIbIIIa) when activated by the platelet agonist adenosine diphosphate (ADP). Furthermore, washed platelets from Toll-like receptor-2 (Tlr2)-deficient mice likewise showed impaired static deposition to the subendothelial matrix component type I collagen compared with wild-type (WT) controls, a process that was unaffected by GPIbα-blockade but influenced by von Willebrand factor (VWF) plasma levels. Collectively, our results indicate that microbiota-triggered steady-state activation of innate immune pathways via TLR2 enhances platelet deposition to subendothelial matrix molecules. Our results link host colonization status with the ADP-triggered activation of integrin αIIbβ3, a pathway promoting platelet deposition to the growing thrombus.
Collapse
Affiliation(s)
- Klytaimnistra Kiouptsi
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Sven Jäckel
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Eivor Wilms
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Giulia Pontarollo
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Jana Winterstein
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Cornelia Karwot
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Kathrin Groß
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
- German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, 55131 Mainz, Germany
| | - Christoph Reinhardt
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg- University of Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany; (K.K.); (S.J.); (E.W.); (G.P.); (J.W.); (C.K.); (K.G.); (K.J.)
- German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, 55131 Mainz, Germany
- Correspondence:
| |
Collapse
|
3
|
Schmidt DE, Lakerveld AJ, Heitink‐Pollé KMJ, Bruin MCA, Vidarsson G, Porcelijn L, de Haas M. Anti-platelet antibody immunoassays in childhood immune thrombocytopenia: a systematic review. Vox Sang 2020; 115:323-333. [PMID: 32080872 PMCID: PMC7317748 DOI: 10.1111/vox.12894] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/17/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND In adult immune thrombocytopenia (ITP), an acquired autoimmune bleeding disorder, anti-platelet autoantibody testing may be useful as a rule-in test. Childhood ITP has different disease characteristics, and the diagnostic and prognostic value of anti-platelet antibody testing remains uncertain. OBJECTIVE To systematically review the diagnostic accuracy of anti-platelet autoantibody testing in childhood ITP. METHODS PubMed and EMBASE were searched for studies evaluating immunoassays in childhood ITP. Study quality was assessed (QUADAS2), and evidence was synthesized descriptively. RESULTS In total, 40 studies (1606 patients) were identified. Nine studies reported sufficient data to determine diagnostic accuracy measures. Anti-platelet IgG antibody testing showed a moderate sensitivity (0·36-0·80 platelet-associated IgG [direct test]; 0·19-0·39 circulating IgG [indirect test]). In studies that reported control data, including patients with non-immune thrombocytopenia, specificity was very good (0·80-1·00). Glycoprotein-specific immunoassays showed comparable sensitivity (three studies) and predominantly identified IgG anti-GP IIb/IIIa antibodies, with few IgG anti-GP Ib/IX antibodies. Anti-platelet IgM antibodies were identified in a substantial proportion of children (sensitivity 0·62-0·64 for direct and indirect tests). CONCLUSION The diagnostic evaluation of IgG and IgM anti-platelet antibodies may be useful as a rule-in test for ITP. In children with insufficient platelets for a direct test, indirect tests may be performed instead. A negative test does not rule out the diagnosis of ITP. Future studies should evaluate the value of anti-platelet antibody tests in thrombocytopenic children with suspected ITP.
Collapse
Affiliation(s)
- David E. Schmidt
- Sanquin ResearchDepartment of Experimental ImmunohematologyAmsterdamThe Netherlands
- Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Anke J. Lakerveld
- Sanquin ResearchDepartment of Experimental ImmunohematologyAmsterdamThe Netherlands
- Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | | | - Marrie C. A. Bruin
- Department of Pediatric HematologyUniversity Medical Center UtrechtUtrechtThe Netherlands
- Princess Maxima Center for Pediatric OncologyUtrechtThe Netherlands
| | - Gestur Vidarsson
- Sanquin ResearchDepartment of Experimental ImmunohematologyAmsterdamThe Netherlands
- Landsteiner LaboratoryAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Leendert Porcelijn
- Department of Immunohematology DiagnosticsSanquin Diagnostic ServicesAmsterdamThe Netherlands
| | - Masja de Haas
- Department of Immunohematology DiagnosticsSanquin Diagnostic ServicesAmsterdamThe Netherlands
- Sanquin ResearchCenter for Clinical Transfusion ResearchLeidenThe Netherlands
- Jon J van Rood Center for Clinical Transfusion ScienceLeiden University Medical CenterLeidenThe Netherlands
- Department of Immunohematology and Blood TransfusionLeiden University Medical CenterThe Netherlands
| |
Collapse
|
4
|
Chen Y, Xie Y, Ruan M, Shi J. The Levels of T Lymphocyte Subsets in Immune Thrombocytopenia Associated with Anti-GPIIb/IIIa- and/or Anti-GPIbα-Mediated Responses Are Differentially Sensitive to Dexamethasone. Acta Haematol 2018; 140:60-66. [PMID: 30130794 DOI: 10.1159/000491977] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/24/2018] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The aim of this work was to investigate the influence of T lymphocyte subsets and platelet-specific autoantibodies on immune thrombocytopenia (ITP) with dexamethasone therapy. METHODS The samples were obtained from patients before therapy. T lymphocyte subsets were measured by flow cytometry, and platelet-specific autoantibodies were evaluated by modified monoclonal antibody immobilization of platelet antigen assay. RESULTS A total of 50 ITP patients were involved in the study. Twenty-three were anti-GPIbα antibody positive and were treated with dexamethasone, with a response rate of 47.8%. Twenty-seven cases were anti-GPIbα antibody negative, with a response rate of 77.8%. A significant difference was detected (p < 0.05). The level of CD4+ T lymphocytes in ITP patients was lower compared with the control group (p < 0.05). The level of CD8+ T lymphocytes was higher than that in the normal controls (p < 0.05). Additionally, the patients with a higher level of CD8+ T lymphocytes and lower level of CD4+ T lymphocytes were more likely to respond to dexamethasone treatment. Moreover, we observed that ITP patients associated with anti-GPIIb/IIIa antibodies had lower levels of CD4+ T lymphocytes and higher CD8+ T lymphocyte levels. CONCLUSIONS There was insensitivity to dexamethasone treatment in ITP patients who were anti-GPIbα antibody positive. The detection of T lymphocyte subsets is useful in ITP patients for forecasting the outcome of dexamethasone treatment. There were some relationships between the different antibodies and the levels of T lymphocyte subsets.
Collapse
Affiliation(s)
- Yang Chen
- Department of Hematology, The Affilated Jiangning Hospital of Nanjing Medical University, Nanjing, China
| | - Yanyan Xie
- Department of Intensive Care Unit, The Affilated Jiangning Hospital of Nanjing Medical University, Nanjing, China
| | - Min Ruan
- Department of Hematology, The First Affilated Hospital of Anhui Medical University, Hefei, China
| | - Jinning Shi
- Department of Hematology, The Affilated Jiangning Hospital of Nanjing Medical University, Nanjing, China
| |
Collapse
|
5
|
Jallu V, Beranger T, Bianchi F, Casale C, Chenet C, Ferre N, Philippe S, Quesne J, Martageix C, Petermann R. Cab4b, the first human platelet antigen carried by glycoprotein IX discovered in a context of severe neonatal thrombocytopenia. J Thromb Haemost 2017; 15:1646-1654. [PMID: 28561420 DOI: 10.1111/jth.13744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Indexed: 11/28/2022]
Abstract
Essentials Life-threatening maternofetal thrombocytopenias mostly depend on αIIb β3 antigens. We performed serological, genomic and in vitro studies of two life-threatening thrombocytopenias. Identification of a c.368C>T variation leading to Pro123Leu substitution in GPIX. A rare GPIX variant reported in a genomic database define a new alloantigen. SUMMARY Background After three miscarriages, a 39-year-old woman gave birth, with a 1-year interval, to two severely thrombocytopenic neonates (4 ×109 L-1 and 33 ×109 L-1 ) with intracranial hemorrhages. Transfusion of platelet concentrates corrected the thrombocytopenia. The outcome was favorable for the first child, but the second one died 10 days after cesarean delivery (31 weeks of gestation + 6 days). Methods Serologic studies were performed with mAb-specific immobilization of platelet antigens and flow cytometry techniques. Human platelet alloantigen (HPA) genotyping was performed with the BioArray HPA BeadChip and PCR-sequence-specific primer techniques. Genomic DNA was studied by direct sequencing of PCR products. The mutant glycoprotein (GP) was expressed in transiently transfected HEK293 cells. Results In MAIPA assay, the maternal serum faintly reacted with GPIbIX from paternal and child 1 platelets, but not with maternal or panel platelets. No maternofetal incompatibility was found in the 22 known HPA systems, tested except for HPA-1b in child 2. A new alloantigen carried by GPIbIX was suspected. Genomic sequencing revealed a paternal GPIX variation (NM_000174.4:c.368C>T). The father and children were heterozygous and incompatible with the mother, who was NM_000174.4:c.368C homozygous. The maternal serum reacted with the GPIX NP_000165.1:p.Leu123 form coexpressed with GPIb in transfected HEK293 cells. The NM_000174.4:c.368T allele (rs202229101) has a minor allele frequency of 0.0002, and was not detected in 120 French subjects (families with fetal and neonatal alloimmune thrombocytopenia [FNAIT]), suggesting that it is rarely implicated in alloimmunization. Conclusion The NP_000165.1:p.Leu123 allele named Cab4b is the first platelet alloantigen described on GPIX. In the absence of other known maternofetal incompatibility, the child 1 case suggests that anti-Cab4b alloantibodies can induce severe thrombocytopenias.
Collapse
Affiliation(s)
- V Jallu
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - T Beranger
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - F Bianchi
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - C Casale
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - C Chenet
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - N Ferre
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - S Philippe
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - J Quesne
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - C Martageix
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - R Petermann
- Département d'Immunologie Plaquettaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| |
Collapse
|
6
|
Liang X, Syed AK, Russell SR, Ware J, Li R. Dimerization of glycoprotein Ibα is not sufficient to induce platelet clearance. J Thromb Haemost 2016; 14:381-6. [PMID: 26662889 PMCID: PMC4755834 DOI: 10.1111/jth.13221] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/22/2015] [Indexed: 01/10/2023]
Abstract
UNLABELLED ESSENTIALS: Many anti-glycoprotein (GP)Ibα antibodies induce platelet clearance in a dimer-dependent manner. Characterization of monoclonal antibodies that bind the mechanosensitive domain (MSD) of GPIbα. An anti-MSD antibody binds two copies of GPIbα in platelets but does not induce platelet clearance. The prevailing clustering model of GPIbα signaling is incorrect or needs revision. BACKGROUND The mechanism of platelet clearance is not clear. Many antibodies binding the membrane-distal ligand-binding domain of glycoprotein (GP)Ibα induce rapid clearance of platelets and acute thrombocytopenia, which requires the bifurcated antibody structure. It was thought that binding of these antibodies induced lateral dimerization or clustering of GPIbα in the plasma membrane, which leads to downstream signaling and platelet clearance. However, many antibodies targeting GPIbβ and GPIX, which are associated with GPIbα in the GPIb-IX complex, do not induce platelet clearance, which is in contradiction to the clustering model. OBJECTIVES To test whether dimerization or clustering of GPIbα is sufficient to transmit the signal that leads to platelet clearance. METHODS We have recently raised several mAbs targeting the mechanosensitive domain (MSD) of GPIbα. Binding of these anti-MSD antibodies was characterized with biochemical methods. Their ability to stimulate platelets and induce platelet clearance in mice was assessed. RESULTS AND CONCLUSION Infusion of anti-MSD antibodies does not cause thrombocytopenia in mice. These antibodies show no detectable effects on platelet activation and aggregation in vitro. Further biochemical investigation showed that the anti-MSD antibody 3D1 binds two copies of GPIbα on the platelet surface. Therefore, lateral dimerization of GPIbα induced by antibody binding is not sufficient to initiate GPIb-IX signaling and induce platelet clearance. Our results suggest that a factor other than or in addition to clustering of GPIbα is required to induce platelet clearance.
Collapse
Affiliation(s)
- Xin Liang
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - Anum K. Syed
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - Susan R. Russell
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Jerry Ware
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| |
Collapse
|
7
|
Liu YX, Zhang F, Yao QM, Yuan T, Xu J, Zhu XJ. Expression of CD11a in lymphocyte subpopulation in immune thrombocytopenia. Int J Clin Exp Pathol 2015; 8:15642-15651. [PMID: 26884833 PMCID: PMC4730046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 11/28/2015] [Indexed: 06/05/2023]
Abstract
Recent research demonstrates that the underlying mechanism in immune thrombocytopenia (ITP) is very complex. Lymphocyte function associated antigen-1 (LFA-1) plays important roles in autoimmune diseases. The purpose of this study was to investigate the expression of CD11a on lymphocytes and explore its possible role in ITP. The expression of CD11a on lymphocyte subpopulations (CD3(+) T cells, CD3(+)CD4(+) T cells, CD3(+)CD4(-) T cells, CD4(+)Foxp3(+) T regulatory cells and CD19(+) B cells) were analyzed by flow cytometry. Specific anti-platelet GPIIb/IIIa and/or GPIb/IX autoantibodies were assayed by modified monoclonal antibody specific immobilization of platelet antigens (MAIPA). The mean fluorescence intensity of CD11a on CD3(+) T, CD3(+)CD4(-) T and CD19(+) B lymphocytes were increased in ITP patients compared to healthy controls. No significant difference of CD11a expression on CD3(+)CD4(+) T cells or CD4(+)Foxp3(+) T regulatory cells was found between ITP patients and controls. Our data indicates the possible role of CD11a in the pathogenesis of ITP.
Collapse
Affiliation(s)
- Yan-Xia Liu
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University Jinan 250021, China
| | - Feng Zhang
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University Jinan 250021, China
| | - Qing-Min Yao
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University Jinan 250021, China
| | - Ting Yuan
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University Jinan 250021, China
| | - Jian Xu
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University Jinan 250021, China
| | - Xiao-Juan Zhu
- Department of Hematology, Shandong Provincial Hospital Affiliated to Shandong University Jinan 250021, China
| |
Collapse
|
8
|
Yougbaré I, Lang S, Yang H, Chen P, Zhao X, Tai WS, Zdravic D, Vadasz B, Li C, Piran S, Marshall A, Zhu G, Tiller H, Killie MK, Boyd S, Leong-Poi H, Wen XY, Skogen B, Adamson SL, Freedman J, Ni H. Maternal anti-platelet β3 integrins impair angiogenesis and cause intracranial hemorrhage. J Clin Invest 2015; 125:1545-56. [PMID: 25774504 DOI: 10.1172/jci77820] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 02/05/2015] [Indexed: 01/09/2023] Open
Abstract
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a life-threatening disease in which intracranial hemorrhage (ICH) is the major risk. Although thrombocytopenia, which is caused by maternal antibodies against β3 integrin and occasionally by maternal antibodies against other platelet antigens, such as glycoprotein GPIbα, has long been assumed to be the cause of bleeding, the mechanism of ICH has not been adequately explored. Utilizing murine models of FNAIT and a high-frequency ultrasound imaging system, we found that ICH only occurred in fetuses and neonates with anti-β3 integrin-mediated, but not anti-GPIbα-mediated, FNAIT, despite similar thrombocytopenia in both groups. Only anti-β3 integrin-mediated FNAIT reduced brain and retina vessel density, impaired angiogenic signaling, and increased endothelial cell apoptosis, all of which were abrogated by maternal administration of intravenous immunoglobulin (IVIG). ICH and impairment of retinal angiogenesis were further reproduced in neonates by injection of anti-β3 integrin, but not anti-GPIbα antisera. Utilizing cultured human endothelial cells, we found that cell proliferation, network formation, and AKT phosphorylation were inhibited only by murine anti-β3 integrin antisera and human anti-HPA-1a IgG purified from mothers with FNAIT children. Our data suggest that fetal hemostasis is distinct and that impairment of angiogenesis rather than thrombocytopenia likely causes FNAIT-associated ICH. Additionally, our results indicate that maternal IVIG therapy can effectively prevent this devastating disorder.
Collapse
MESH Headings
- Animals
- Antibody Specificity
- Antigens, Human Platelet/immunology
- Apoptosis
- Autoantigens/immunology
- Blood Platelets/immunology
- Brain/blood supply
- Brain/embryology
- Disease Models, Animal
- Female
- Fetal Blood/immunology
- Human Umbilical Vein Endothelial Cells
- Humans
- Immune Sera/toxicity
- Immunity, Maternally-Acquired
- Immunoglobulin G/immunology
- Immunoglobulins, Intravenous/therapeutic use
- Integrin beta3/genetics
- Integrin beta3/immunology
- Intracranial Hemorrhages/embryology
- Intracranial Hemorrhages/etiology
- Intracranial Hemorrhages/immunology
- Intracranial Hemorrhages/physiopathology
- Male
- Maternal-Fetal Exchange
- Mice
- Mice, Knockout
- Neovascularization, Pathologic/etiology
- Neovascularization, Physiologic/immunology
- Platelet Glycoprotein GPIb-IX Complex/genetics
- Platelet Glycoprotein GPIb-IX Complex/immunology
- Pregnancy
- Proto-Oncogene Proteins c-akt/physiology
- Retinal Vessels/embryology
- Retinal Vessels/pathology
- Thrombocytopenia, Neonatal Alloimmune/embryology
- Thrombocytopenia, Neonatal Alloimmune/immunology
- Thrombocytopenia, Neonatal Alloimmune/prevention & control
Collapse
|
9
|
Kashiwagi H, Tomiyama Y. [Management of idiopathic thrombocytopenic purpura (primary immune thrombocytopenia, ITP)]. Rinsho Ketsueki 2014; 55:2087-2094. [PMID: 25297775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
MESH Headings
- Antibodies, Monoclonal, Murine-Derived/administration & dosage
- Benzoates/administration & dosage
- Biomarkers/blood
- Dexamethasone/administration & dosage
- Drug Therapy, Combination
- Gastritis/complications
- Gastritis/drug therapy
- Gastritis/microbiology
- Helicobacter Infections
- Helicobacter pylori
- Humans
- Hydrazines/administration & dosage
- Platelet Glycoprotein GPIIb-IIIa Complex/immunology
- Platelet Glycoprotein GPIb-IX Complex/immunology
- Prednisolone/administration & dosage
- Purpura, Thrombocytopenic, Idiopathic/diagnosis
- Purpura, Thrombocytopenic, Idiopathic/etiology
- Purpura, Thrombocytopenic, Idiopathic/therapy
- Pyrazoles/administration & dosage
- Receptors, Fc/administration & dosage
- Receptors, Thrombopoietin/agonists
- Recombinant Fusion Proteins/administration & dosage
- Rituximab
- Splenectomy
- Thrombopoietin/administration & dosage
- Thrombopoietin/blood
Collapse
|
10
|
Peng J, Ma SH, Liu J, Hou Y, Liu XM, Niu T, Xu RR, Guo CS, Wang XM, Cheng YF, Ni H, Hou M. Association of autoantibody specificity and response to intravenous immunoglobulin G therapy in immune thrombocytopenia: a multicenter cohort study. J Thromb Haemost 2014; 12:497-504. [PMID: 24517219 DOI: 10.1111/jth.12524] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 01/31/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder, in which platelet glycoprotein (GP)IIb-IIIa and GPIb-IX are the two most frequently targeted autoantigens. Our previous studies in animal models of ITP demonstrated that intravenous immunoglobulin G (IVIG) could protect against anti-GPIIb-IIIa autoantibody-mediated thrombocytopenia but failed to ameliorate ITP induced by most anti-GPIb-IX autoantibodies. OBJECTIVES The objective of this human study was to evaluate the association between the specificity of antiplatelet autoantibodies and response to IVIG treatment. PATIENTS/METHODS In this retrospective study, a cohort of 156 previously untreated adults with severe ITP who underwent IVIG therapy (0.4 g kg(-1) day(-1) for 5 days) was analyzed. The primary outcome was response defined as platelet counts of ≥ 30 × 10(9) L(-1) and a doubling of baseline counts within 7 days of dosing, and an absence of bleeding. RESULTS AND CONCLUSIONS Among the 66 patients with anti-GPIb-IX autoantibodies, only 24 (36.4%) achieved a response, as compared with 72 of 90 patients (80.0%) who were negative for anti-GPIb-IX autoantibodies (relative risk 2.2; 95% confidence interval 1.6-3.1). This study found no difference in response between patients with anti-GPIIb-IIIa autoantibodies (61.7%) and those without anti-GPIIb-IIIa autoantibodies (61.3%). Logistic regressions, including main effects and the interaction between these two autoantibodies, showed no influence of anti-GPIIb-IIIa autoantibodies on the effects of anti-GPIb-IX autoantibodies with regard to their association with IVIG response. Thus, in adults with ITP, the presence of anti-GPIb-IX autoantibodies is a predictive factor for poor response to IVIG treatment. TRIAL REGISTRATION ClinicalTrials.gov NCT01666795.
Collapse
Affiliation(s)
- J Peng
- Qilu Hospital, Shandong University, Jinan, China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Kuwana M, Okazaki Y, Ikeda Y. Detection of circulating B cells producing anti-GPIb autoantibodies in patients with immune thrombocytopenia. PLoS One 2014; 9:e86943. [PMID: 24466297 PMCID: PMC3899372 DOI: 10.1371/journal.pone.0086943] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/17/2013] [Indexed: 11/19/2022] Open
Abstract
Background We previously reported that an enzyme-linked immunospot (ELISPOT) assay for detecting anti-GPIIb/IIIa antibody-secreting B cells is a sensitive method for identifying patients with immune thrombocytopenia (ITP). Here we assessed the clinical significance of measuring circulating B cells producing antibodies to GPIb, another major platelet autoantigen. Methods Anti-GPIb and anti-GPIIb/IIIa antibody-producing B cells were simultaneously measured using ELISPOT assays in 32 healthy controls and 226 consecutive thrombocytopenic patients, including 114 with primary ITP, 25 with systemic lupus erythematosus (SLE), 30 with liver cirrhosis, 39 with post-hematopoietic stem cell transplantation (post-HSCT), and 18 non-ITP controls (aplastic anemia and myelodysplastic syndrome). Results There were significantly more circulating anti-GPIb and anti-GPIIb/IIIa antibody-producing B cells in primary ITP, SLE, liver cirrhosis, and post-HSCT patients than in healthy controls (P<0.05 for all comparisons). For diagnosing primary ITP, the anti-GPIb ELISPOT assay had 43% sensitivity and 89% specificity, whereas the anti-GPIIb/IIIa ELISPOT assay had 86% sensitivity and 83% specificity. When two tests were combined, the sensitivity was slightly improved to 90% without a reduction in specificity. In primary ITP patients, the anti-GPIb antibody response was associated with a low platelet count, lack of Helicobacter pylori infection, positive anti-nuclear antibody, and poor therapeutic response to intravenous immunoglobulin. Conclusion The ELISPOT assay for detecting anti-GPIb antibody-secreting B cells is useful for identifying patients with ITP, but its utility for diagnosing ITP is inferior to the anti-GPIIb/IIIa ELISPOT assay. Nevertheless, detection of the anti-GPIb antibody response is useful for subtyping patients with primary ITP.
Collapse
Affiliation(s)
- Masataka Kuwana
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
- * E-mail:
| | - Yuka Okazaki
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Yasuo Ikeda
- Faculty of Science and Engineering, Waseda University, Japan
| |
Collapse
|
12
|
Loskutova TA, Turchin VN. [Prognosis of hypertensive disorders in pregnancy]. Lik Sprava 2013:25-31. [PMID: 25509911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There has been dependence of probability of hypertensive disorders for pregnant women on level of antibodies to β2 glycoprotein 1, D-dimer, coefficient of atherogenicity and results of testing thrombophilia genes. This allows detecting pregnant women having high risk of hypertensive disorders. Testing of the model on a sample which consists of 44 healthy pregnant women and 112 women with hypertensive disorders has good predictive properties.
Collapse
|
13
|
Liu XF, Xue F, Zhang L, Zhou XL, Liu YZ, Liu W, Chen YF, Huang YT, Yang RC. [Relationship between the expression of autoantibodies against platelet membrane glycoprotein and therapeutic effect in primary immune thrombocytopenia]. Zhonghua Xue Ye Xue Za Zhi 2013; 34:610-613. [PMID: 23906456 DOI: 10.3760/cma.j.issn.0253-2727.2013.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE To study the expression of specific anti- platelet glycoprotein autoantibodies GP II b/III a, GP I b/IX and GP I a/II a in primary immune thrombocytopenia (ITP), and to evaluate the relationship between the therapeutic effect and the expression of specific anti- platelet glycoprotein antibodies GPIIb/IIIa, GPIb/IX and GPIa/IIa. METHODS Anti-GPIIb/IIIa, GPIb/ IX and GP I a/II a antibodies were assayed by ELISA for patients with ITP. Total 442 patients in our hospital, who were retrospectively investigated from December 2010 to November 2012, were divided into newly diagnosed ITP, persistent and chronic ITP. The expression of specific anti- platelet glycoprotein antibody in each group was measured separately. The newly diagnosed ITP patients were treated with intravenous IgG (IVIG) and corticosteroids. The relationship between the expression of specific anti- platelet glycoprotein antibodies GPIIb/IIIa, GPIb/IX and GPIa/IIa and the complete response (CR) was studied. RESULTS Positive rates of anti- platelet glycoprotein antibodies were 59.09%, 26.97% and 37.35% respectively in newly diagnosed ITP, persistent and chronic ITP, the difference was statistical significant (P<0.05). In newly diagnosed ITP, positive rate of antibody against GPIIb/IIIa was 38.64%, double positive rate of antibodies against both GP II b/III a and GP I a/II a was 15.91%, there was statistical significance (P<0.05) compared with that of persistent and chronic ITP. The complete response (CR) rate in newly diagnosed ITP patients with positive antibody against GP II b/III a was 80.39% after treatment with IVIG and corticosteroids. There was statistical significance compared with that in patients having no antibodies (P<0.05). CONCLUSION The expression of antibodies against GP II b/III a and double positive for both GP II b/III a and GP I a/II a autoantibodies increased in newly diagnosed ITP patients. Patients with anti-GP II b/III a autoantibody had good response to medication with IVIG and corticosteroids.
Collapse
Affiliation(s)
- Xiao-fan Liu
- Institute of Hematology & Blood Diseases Hospital, CAMS & PUMC, Tianjin 300020, China
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Urbanus RT, van der Wal DE, Koekman CA, Huisman A, van den Heuvel DJ, Gerritsen HC, Deckmyn H, Akkerman JWN, Schutgens REG, Gitz E. Patient autoantibodies induce platelet destruction signals via raft-associated glycoprotein Ibα and Fc RIIa in immune thrombocytopenia. Haematologica 2013; 98:e70-2. [PMID: 23716547 DOI: 10.3324/haematol.2013.087874] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
|
15
|
Nishimoto T, Satoh T, Simpson EK, Ni H, Kuwana M. Predominant autoantibody response to GPIb/IX in a regulatory T-cell-deficient mouse model for immune thrombocytopenia. J Thromb Haemost 2013; 11:369-72. [PMID: 23176290 DOI: 10.1111/jth.12079] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/07/2012] [Indexed: 01/28/2023]
MESH Headings
- Animals
- Autoantibodies/blood
- Autoimmunity
- Blood Platelets/immunology
- Cells, Cultured
- Disease Models, Animal
- Immunoglobulin G/blood
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Mice, Nude
- Platelet Glycoprotein GPIIb-IIIa Complex/genetics
- Platelet Glycoprotein GPIIb-IIIa Complex/immunology
- Platelet Glycoprotein GPIb-IX Complex/genetics
- Platelet Glycoprotein GPIb-IX Complex/immunology
- Purpura, Thrombocytopenic, Idiopathic/blood
- Purpura, Thrombocytopenic, Idiopathic/immunology
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/transplantation
- Time Factors
Collapse
|
16
|
Doi T, Tokuda H, Matsushima-Nishiwaki R, Cuong NT, Kageyama Y, Iida Y, Kondo A, Akamatsu S, Otsuka T, Iida H, Kozawa O, Ogura S. Effect of antithrombin III on glycoprotein Ib/IX/V activation in human platelets: suppression of thromboxane A2 generation. Prostaglandins Leukot Essent Fatty Acids 2012; 87:57-62. [PMID: 22819492 DOI: 10.1016/j.plefa.2012.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 04/12/2012] [Accepted: 05/24/2012] [Indexed: 11/18/2022]
Abstract
We have previously shown that ristocetin, an activator of glycoprotein Ib/IX/V, induces release of soluble CD40 (sCD40) ligand via thromboxane (TX) A(2) production from human platelets. In the present study, we investigated the effect of antithrombin-III (AT-III), an anticoagulant, on the ristocetin-induced glycoprotein Ib/IX/V activation in human platelets. AT-III inhibited ristocetin-stimulated platelet aggregation. The ristocetin-induced production of 11-dehydro-TXB(2), a stable metabolite of TXA(2), and the release of sCD40 ligand were suppressed by AT-III. AT-III also reduced the ristocetin-stimulated secretion of platelet-derived growth factor (PDGF)-AB. AT-III failed to affect U46619-, a TXA(2) receptor agonist, induced levels of p38 mitogen-activated protein kinase phosphorylation or sCD40 ligand release. AT-III reduced the binding of SZ2, a monoclonal antibody to the sulfated sequence in the α-chain of glycoprotein Ib, to the ristocetin-stimulated platelets. These results strongly suggest that AT-III reduced ristocetin-stimulated release of sCD40 ligand due to inhibiting TXA(2) production in human platelets.
Collapse
Affiliation(s)
- Tomoaki Doi
- Department of Emergency and Disaster Medicine, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Fang X, Fang Y, Liu L, Liu G, Wu J. Mapping paratope on antithrombotic antibody 6B4 to epitope on platelet glycoprotein Ibalpha via molecular dynamic simulations. PLoS One 2012; 7:e42263. [PMID: 22860101 PMCID: PMC3408434 DOI: 10.1371/journal.pone.0042263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 07/04/2012] [Indexed: 11/19/2022] Open
Abstract
Binding of platelet receptor glycoprotein Ibα (GPIbα) to the A1 domain of von Willebrand factor (vWF) is a critical step in both physiologic hemostasis and pathologic thrombosis, for initiating platelet adhesion to subendothelium of blood vessels at sites of vascular injury. Gain-of-function mutations in GPIbα contribute to an abnormally high-affinity binding of platelets to vWF and can lead to thrombosis, an accurate complication causing heart attack and stroke. Of various antithrombotic monoclonal antibodies (mAbs) targeting human GPIbα, 6B4 is a potent one to inhibit the interaction between GPIbα and vWF-A1 under static and flow conditions. Mapping paratope to epitope with mutagenesis experiments, a traditional route in researches of these antithrombotic mAbs, is usually expensive and time-consuming. Here, we suggested a novel computational procedure, which combines with homology modeling, rigid body docking, free and steered molecular dynamics (MD) simulations, to identify key paratope residues on 6B4 and their partners on GPIbα, with hypothesis that the stable hydrogen bonds and salt bridges are the important linkers between paratope and epitope residues. Based on a best constructed model of 6B4 bound with GPIbα, the survival ratios and rupture times of all detected hydrogen bonds and salt bridges in binding site were examined via free and steered MD simulations and regarded as indices of thermal and mechanical stabilizations of the bonds, respectively. Five principal paratope residues with their partners were predicted with their high survival ratios and/or long rupture times of involved hydrogen bonds, or with their hydrogen bond stabilization indices ranked in top 5. Exciting, the present results were in good agreement with previous mutagenesis experiment data, meaning a wide application prospect of our novel computational procedure on researches of molecular of basis of ligand-receptor interactions, various antithrombotic mAbs and other antibodies as well as theoretically design of biomolecular drugs.
Collapse
Affiliation(s)
- Xiang Fang
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
| | - Ying Fang
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
- * E-mail: (YF); (JW)
| | - Li Liu
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
| | - Guangjian Liu
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
| | - Jianhua Wu
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China
- * E-mail: (YF); (JW)
| |
Collapse
|
18
|
Arnold DM, Santoso S, Greinacher A. Recommendations for the implementation of platelet autoantibody testing in clinical trials of immune thrombocytopenia. J Thromb Haemost 2012; 10:695-7. [PMID: 22332994 PMCID: PMC4854629 DOI: 10.1111/j.1538-7836.2012.04664.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- D M Arnold
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | | |
Collapse
|
19
|
Zhou XL, Yan S, Li Q, Li P, Zhou ZP, Yang RC. [A novel diagnostic measure of platelet-specific antibody in immune thrombocytopenia]. Zhonghua Xue Ye Xue Za Zhi 2012; 33:200-203. [PMID: 22781607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To detect the platelet glycoprotein-specific antibodies in serum of thrombocytopenia patients and evaluate its diagnostic value for immune thrombocytopenia. METHOD Anti-GPIIb/IIIa, GPIb/IX and GPIa/IIa antibodies were assayed by ELISA kit (PAKUTO) in patients with thrombocytopenia. RESULTS The sensitivity and specificity of PAKAUTO in immune thrombocytopenia were 44.0% and 95.7%, respectively. The values of positive and negative predictions were 98.0% and 26.2%, respectively. Among those PAKAUTO positive patients, positive rates of GPIIb/IIIa, GPIa/IIa and GPIb/IX were 87%, 35% and 10%, respectively. The positive rate of patients not received immune suppressive agents (58.5%) was significantly higher than those received immune suppressive agents (26.9%) (P < 0.01). The positive rate of patients with platelet count ≤ 20 × 10(9)/L (51.6%) was significantly higher than those with platelet count > 20 × 10(9)/L (27.8%) (P < 0.01). The positive rate of patients with secondary immune thrombocytopenia (66.7%) was significantly higher than those with primary immune thrombocytopenia (41.7%) (P < 0.05). CONCLUSION The highly specific method (PAKAUTO) could effectively differentiate immune or non-immune thrombocytopenia and be applied to diagnosis of immune thrombocytopenia.
Collapse
Affiliation(s)
- Xue-li Zhou
- Chinese Academy of Medical Sciences, Tianjin, China
| | | | | | | | | | | |
Collapse
|
20
|
Li C, Piran S, Chen P, Lang S, Zarpellon A, Jin JW, Zhu G, Reheman A, van der Wal DE, Simpson EK, Ni R, Gross PL, Ware J, Ruggeri ZM, Freedman J, Ni H. The maternal immune response to fetal platelet GPIbα causes frequent miscarriage in mice that can be prevented by intravenous IgG and anti-FcRn therapies. J Clin Invest 2011; 121:4537-47. [PMID: 22019589 PMCID: PMC3204841 DOI: 10.1172/jci57850] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 08/26/2011] [Indexed: 11/17/2022] Open
Abstract
Fetal and neonatal immune thrombocytopenia (FNIT) is a severe bleeding disorder caused by maternal antibody-mediated destruction of fetal/neonatal platelets. It is the most common cause of severe thrombocytopenia in neonates, but the frequency of FNIT-related miscarriage is unknown, and the mechanism(s) underlying fetal mortality have not been explored. Furthermore, although platelet αIIbβ3 integrin and GPIbα are the major antibody targets in immune thrombocytopenia, the reported incidence of anti-GPIbα-mediated FNIT is rare. Here, we developed mouse models of FNIT mediated by antibodies specific for GPIbα and β3 integrin and compared their pathogenesis. We found, unexpectedly, that miscarriage occurred in the majority of pregnancies in our model of anti-GPIbα-mediated FNIT, which was far more frequent than in anti-β3-mediated FNIT. Dams with anti-GPIbα antibodies exhibited extensive fibrin deposition and apoptosis/necrosis in their placentas, which severely impaired placental function. Furthermore, anti-GPIbα (but not anti-β3) antiserum activated platelets and enhanced fibrin formation in vitro and thrombus formation in vivo. Importantly, treatment with either intravenous IgG or a monoclonal antibody specific for the neonatal Fc receptor efficiently prevented anti-GPIbα-mediated FNIT. Thus, the maternal immune response to fetal GPIbα causes what we believe to be a previously unidentified, nonclassical FNIT (i.e., spontaneous miscarriage but not neonatal bleeding) in mice. These results suggest that a similar pathology may have masked the severity and frequency of human anti-GPIbα-mediated FNIT, but also point to possible therapeutic interventions.
Collapse
MESH Headings
- Abortion, Spontaneous/etiology
- Abortion, Spontaneous/immunology
- Abortion, Spontaneous/prevention & control
- Animals
- Blood Platelets/immunology
- Disease Models, Animal
- Female
- Histocompatibility Antigens Class I/immunology
- Histocompatibility, Maternal-Fetal/immunology
- Humans
- Immunoglobulins, Intravenous/therapeutic use
- Integrin beta3/genetics
- Integrin beta3/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Platelet Glycoprotein GPIb-IX Complex/genetics
- Platelet Glycoprotein GPIb-IX Complex/immunology
- Pregnancy
- Receptors, Fc/antagonists & inhibitors
- Receptors, Fc/immunology
- Thrombocytopenia, Neonatal Alloimmune/etiology
- Thrombocytopenia, Neonatal Alloimmune/immunology
Collapse
Affiliation(s)
- Conglei Li
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Siavash Piran
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Pingguo Chen
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Sean Lang
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Alessandro Zarpellon
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Joseph W. Jin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Guangheng Zhu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Adili Reheman
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Dianne E. van der Wal
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Elisa K. Simpson
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Ran Ni
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Peter L. Gross
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Jerry Ware
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Zaverio M. Ruggeri
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - John Freedman
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| | - Heyu Ni
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Toronto Platelet Immunobiology Group and Department of Laboratory Medicine, Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada.
Canadian Blood Services, Toronto, Ontario, Canada.
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Department of Medicine and
Department of Physiology, University of Toronto, Ontario, Canada
| |
Collapse
|
21
|
Sivaraman B, Latour RA. Delineating the roles of the GPIIb/IIIa and GP-Ib-IX-V platelet receptors in mediating platelet adhesion to adsorbed fibrinogen and albumin. Biomaterials 2011; 32:5365-70. [PMID: 21529934 DOI: 10.1016/j.biomaterials.2011.04.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 04/05/2011] [Indexed: 11/16/2022]
Abstract
Platelet adhesion to adsorbed plasma proteins, such as fibrinogen (Fg), has been conventionally thought to be mediated by the GPIIb/IIIa receptor binding to Arg-Gly-Asp (RGD)-like motifs in the adsorbed protein. In previous studies, we showed that platelet adhesion response to adsorbed Fg and Alb was strongly influenced by the degree of adsorption-induced protein unfolding and that platelet adhesion was only partially blocked by soluble RGD, with RGD-blocked platelets adhering without activation. Based on these results, we hypothesized that in addition to the RGD-specific GPIIb/IIIa receptor, which mediates both adhesion and activation, a non-RGD-specific receptor set likely also plays a role in platelet adhesion (but not activation) to both Fg and albumin (Alb). To identify and elucidate the role of these receptors, in addition to GPIIb/IIIa, we also examined the GPIb-IX-V receptor complex, which has been shown to mediate platelet adhesion (but not activation) in studies by other groups. The platelet suspension was pretreated with either a GPIIb/IIIa-antagonist drug Aggrastat(®) or monoclonal antibodies 6B4 or 24G10 against GPIb-IX-V prior to adhesion on Fg- and Alb-coated OH- and CH(3)-functionalized alkanethiol self-assembled monolayer surfaces. The results revealed that GPIIb/IIIa is the primary receptor set involved in platelet adhesion to adsorbed Fg and Alb irrespective of their degree of adsorption-induced unfolding, while the GPIb-IX-V receptor complex plays an insignificant role. Overall, these studies provide novel insights into the molecular-level mechanisms mediating platelet interactions with adsorbed plasma proteins, thereby assisting the biomaterials field develop potent strategies for inhibiting platelet-protein interactions in the design of more hemocompatible cardiovascular biomaterials and effective anti-thrombotic therapies.
Collapse
Affiliation(s)
- Balakrishnan Sivaraman
- Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, United States
| | | |
Collapse
|
22
|
Pham M, Helluy X, Kleinschnitz C, Kraft P, Bartsch AJ, Jakob P, Nieswandt B, Bendszus M, Stoll G. Sustained reperfusion after blockade of glycoprotein-receptor-Ib in focal cerebral ischemia: an MRI study at 17.6 Tesla. PLoS One 2011; 6:e18386. [PMID: 21483769 PMCID: PMC3069968 DOI: 10.1371/journal.pone.0018386] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 03/05/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Inhibition of early platelet adhesion by blockade of glycoprotein-IB (GPIb) protects mice from ischemic stroke. To elucidate underlying mechanisms in-vivo, infarct development was followed by ultra-high field MRI at 17.6 Tesla. METHODS Cerebral infarction was induced by transient-middle-cerebral-artery-occlusion (tMCAO) for 1 hour in C57/BL6 control mice (N = 10) and mice treated with 100 µg Fab-fragments of the GPIb blocking antibody p0p/B 1 h after tMCAO (N = 10). To control for the effect of reperfusion, additional mice underwent permanent occlusion and received anti-GPIb treatment (N = 6; pMCAO) or remained without treatment (N = 3; pMCAO). MRI 2 h and 24 h after MCAO measured cerebral-blood-flow (CBF) by continuous arterial-spin labelling, the apparent-diffusion-coefficient (ADC), quantitative-T2 and T2-weighted imaging. All images were registered to a standard mouse brain MRI atlas and statistically analysed voxel-wise, and by cortico-subcortical ROI analysis. RESULTS Anti-GPIb treatment led to a relative increase of postischemic CBF vs. controls in the cortical territory of the MCA (2 h: 44.2±6.9 ml/100 g/min versus 24 h: 60.5±8.4; p = 0.0012, F((1,18)) = 14.63) after tMCAO. Subcortical CBF 2 h after tMCAO was higher in anti-GPIb treated animals (45.3±5.9 vs. controls: 33.6±4.3; p = 0.04). In both regions, CBF findings were clearly related to a lower probability of infarction (Cortex/Subcortex of treated group: 35%/65% vs. controls: 95%/100%) and improved quantitative-T2 and ADC. After pMCAO, anti-GPIb treated mice developed similar infarcts preceded by severe irreversible hypoperfusion as controls after tMCAO indicating dependency of stroke protection on reperfusion. CONCLUSION Blockade of platelet adhesion by anti-GPIb-Fab-fragments results in substantially improved CBF early during reperfusion. This finding was in exact spatial correspondence with the prevention of cerebral infarction and indicates in-vivo an increased patency of the microcirculation. Thus, progression of infarction during early ischemia and reperfusion can be mitigated by anti-platelet treatment.
Collapse
Affiliation(s)
- Mirko Pham
- Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Wang R, Qin P, Ji XB, Hou M. [The impact of platelet membrane autoantibodies on high-dose dexamethasone therapy in patients with idiopathic thrombocytopenic purpura]. Zhonghua Xue Ye Xue Za Zhi 2009; 30:619-621. [PMID: 19954623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To evaluate the impact of platelet membrane glycoprotein (GP)-specific autoantibodies on high-dose dexamethasone therapy in patients with idiopathic thrombocytopenic purpura (ITP). METHODS Modified direct monoclonal antibody immobilization of platelet antigen assay (MAIPA) was used to detect platelet GPIIb/IIIa and/or GPI b specific autoantibodies. All patients received oral dexamethasone 40 mg/d for 4 days. RESULTS The response rate of high-dose dexamethasone in GPIIb/IIIa and/or GPIb specific autoantibody-negative patients was significantly different from that of antibody-positive patients (P<0.05). The response rate of GPIIb/IIIa specific autoantibody-positive patients was lower than that of antibody-negative patients (P<0.05). GPIb specific autoantibody had no significant impact on the efficacy of high-dose dexamethasone (P>0.05). CONCLUSION Platelet membrane GPIIb/IIIa-specific autoantibody can be a potential negative indicator for ITP patients'response to high-dose oral dexamethasone.
Collapse
Affiliation(s)
- Rui Wang
- Department of Hematology, the Tumor Center, QiLu Hospital of Shandong University, Jinan 250012, China
| | | | | | | |
Collapse
|
24
|
Xia WJ, Ye X, Fu YS, Xu XZ, Chen YK, Ding HQ, Deng J, Luo GP, Xu R. [Expression of anti-platelet glycoprotein specific antibodies and anti-HLA antibodies in idiopathic thrombocytopenic purpura]. Zhongguo Shi Yan Xue Ye Xue Za Zhi 2009; 17:1032-1035. [PMID: 19698253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In order to investigate the expression of the anti-platelet glycoprotein specific antibodies and anti-HLA antibodies in idiopathic thrombocytopenic purpura (ITP), 45 patients with ITP were selected in this study. An easy PCR-SSP assay was used to detect single-nucleotide polymorphisms or deletion in HPA and HLA systems. The anti-platelet glycoprotein specific antibodies and anti-HLA antibodies in plasma or platelet eluate were tested with a solid phase ELISA. The results indicated that the anti-platelet glycoprotein specific antibodies were detected in plasma or platelet eluate of 45 patients, among which anti-GPIIb/IIIa/and anti-GpIb/IX were most common. Both the anti-platelet glycoprotein specific antibodies and anti-HLA antibodies were found in plasma of 11 patients. Pedigree investigation in 2 patients (case 37 and case 40) was carried out, the results showed that anti-platelet glycoprotein specific antibodies and anti-HLA antibodies detected in 2 patients closely related to incompatibility with platelet antigens and HLA antigens in parents. In conclusion, the results suggested that detection of the anti-platelet glycoprotein specific antibodies and anti-HLA antibodies in plasma or platelet eluate in combination with investigation of clinical manifestation of patients is important for diagnosis of idiopathic thrombocytopenic purpura.
Collapse
Affiliation(s)
- Wen-Jie Xia
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, 510095, Guangdong Province, China
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Tang QM, Shen WD, Zhong ZL, Zhou Y, Wu GG. [Influence of different products of platelet membrane glycoprotein monoclonal antibodies used internationally on tests for monoclonal antibody-specific immobilization of platelet antigens]. Zhongguo Shi Yan Xue Ye Xue Za Zhi 2009; 17:1074-1077. [PMID: 19698264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study was aimed to investigate the influence of different platelet membrane glycoprotein monoclonal antibodies (McAb) which are common used in laboratories on the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) technique according to the request of 14th International Society of Blood Transfusion Platelet Immunology Workshop. 30 participant laboratories were provided with 10 known human platelet antigen (HPA) antibodies, 1 normal serum, 9 different McAbs (against GPIIb/IIIa, GPIa/IIa, GPIb/IX and GPIV respectively), and the same protocol. Each participant laboratory carried out the test as the protocol to compare the results of different McAbs against the same glycoprotein and submitted the data to organizer. The results indicated that in McAbs against GPIIb/IIIa, AP2, Gi-5 and PL2-73 showed higher mean S/CO than that of others; in GPIa/IIa, MBC202.2 and 143.1 showed higher mean S/CO than that of others; in GPIb/IX, 142.11 and CLB-MB45 (CD42b) showed higher mean S/CO than that of others; as to GPIV, 131.4 showed higher mean S/CO. In conclusion, capture effects of various McAbs are different, so that different products of McAbs exert influences on the sensitivity of MAIPA. To use a panel of McAbs against the same glycoprotein may avoid the false negative results.
Collapse
Affiliation(s)
- Qiu-Min Tang
- Nanning Blood Center, Nanning Institute of Transfusion Medicine, Nanning 530003, Guangxi Province, China
| | | | | | | | | |
Collapse
|
26
|
Abstract
In this study we investigated mechanisms of platelet interaction with von Willebrand factor (vWF) induced by activating anti-glycoprotein (GP)IIb-IIIa antibody CRC54 directed against LIBS (ligand-induced binding site epitope) in GPIIIa. It was demonstrated that aggregation of washed platelets (measured in Born aggregometer) could be stimulated by CRC54 not only in the presence of fibrinogen but vWF as well. The level of aggregation induced in the presence of saturating concentrations of vWF (approximately 80 microg/ml) was even higher than that in the presence of 1 mg/ml of fibrinogen. Aggregation supported by vWF unlike fibrinogen supported aggregation was almost completely inhibited not only by GPIIb-IIIa antagonists (F(ab')2 fragment of blocking anti-GPIIb-IIIa antibody CRC64 and peptidomimetic aggrastat) but also by anti-GPIb blocking antibody AK2. Aggregation response induced by CRC54 in the presence of vWF was much lower when normal platelets were substituted with GPIb-deficient platelets and this residual aggregation was not affected by anti-GPIb antibody AK2 but still inhibited by anti-GPIIb-IIIa blocking antibody fragment. CRC54-induced aggregation supported by vWF (as well as by fibrinogen) was only partially inhibited by prostaglandin E1, indicating that at least its initiation does not require activation of platelets. CRC54, both in the presence of vWF and fibrinogen, failed to stimulate serotonin secretion at physiological Ca2+ concentration of 1 mM, although substantial release reaction was detected when Ca2+ concentration was decreased to 0.1 mM. CRC54 could also stimulate platelet interaction with immobilized vWF and fibrinogen. However, unlike platelet aggregation in suspension mediated by flow phase vWF, platelet adhesion to adsorbed vWF (in a same way as to fibrinogen) was inhibited only by GPIIb-IIIa but not GPIb antagonists. The data obtained indicated that vWF support platelet aggregation induced by activating anti-GPIIb-IIIa via interaction with two receptors - activated GPIIb-IIIa and GPIb.
Collapse
|
27
|
Abstract
Rosiglitazone is one of the members in the thiazolidinedione (TZD) class of anti-diabetic agents that have proven efficacy in the treatment of patients with type 2 diabetes. We studied serum from a patient who developed acute, severe thrombocytopenia after exposure to rosiglitazone maleate (Avandia) and proposed the mechanisms for rosiglitazone-induced thrombocytopenia. Tested by flow cytometry, the patient's serum was positive for rosiglitazone-induced antibody with the binding ratio of 5.93 (mean fluorescence intensity, MFI) in the presence of the patient's serum and rosiglitazone in a final concentration of 0.53 mmol/l. The antibody was found to bind both glycoprotein (GP) IIb-IIIa complex and GP Ib/IX complex by MAIPA assay using five different monoclonal antibodies (mAbs) against GP complexes Ib/IX, GPIIb/IIIa or GPIa/IIa. Immunoprecipitation studies showed that both GPIIb/IIIa and GP Ib/IX complex were precipitated by antibody in the presence, but not in the absence of rosiglitazone. These findings provide evidence that immune thrombocytopenia can be caused by sensitivity to the antidiabetic agent rosiglitazone maleate. This report documents the first case of rosiglitazone-induced immune thrombocytopenia.
Collapse
Affiliation(s)
- Xiaojing Liu
- Blood Research Institute, Oakland, California 92690, USA
| | | | | |
Collapse
|
28
|
Yuan YH, Kang JR, Yan R, Cheng H, Zhuang FY, Wang YD, Dai KS. [Preparation and preliminary application of rabbit polyclonal antibodies against intracellular peptides of human platelet glycoprotein GPIbalpha]. Zhonghua Yi Xue Za Zhi 2009; 89:826-830. [PMID: 19595123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To prepare rabbit polyclonal antibodies against intracellular peptides of human platelet glycoprotein GPIbalpha. METHODS Two peptides corresponding to human platelet GPIbalpha C-terminus were synthesized and purified by high-performance liquid chromatography (HPLC). The peptides were cross-linked with keyhole limpet hemocyanin (KLH). Two New Zealand white rabbits were immunized with conjugated peptides for 3 times. The polyclonal antibodies were purified by Ammonium Sulfate Precipitation and identified by dot blotting and ELISA. GPIbalpha intracellular peptides phosphorylation was tested with these polyclonal antibodies by ELISA. RESULTS The titers of the two polyclonal antibodies against the GPIbalpha C-terminus peptides were 1:32 000 and 1:64 000 respectively and both of these antibodies reacted with purified GPIbalpha. CONCLUSIONS Two rabbit polyclonal antibodies against C-terminal peptides of human platelet GPIbalpha have been prepared successfully, providing a way for the preparation of these kinds of antibody. Both phosphorylation and dephosphorylation states exist in the intracellular peptide of human platelets.
Collapse
Affiliation(s)
- Yan-Hong Yuan
- Hematology and Cell Biology Laboratory, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | | | | | | | | | | | | |
Collapse
|
29
|
Webster ML, Zhu G, Li Y, Ni H. Fc-independent phagocytosis: implications for intravenous IgG therapy in immune thrombocytopenia. Cardiovasc Hematol Disord Drug Targets 2008; 8:278-282. [PMID: 19075638 DOI: 10.2174/187152908786786223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Phagocytes were first described 120 years ago. Although the molecular mechanisms involved in initiating phagocytosis (through Fc or other receptors) are still not fully understood, the roles of phagocytes in innate and adaptive immunity have been well studied. Phagocytes in the reticuloendothelial system, particularly macrophages, have been implicated in the clearance of senescent blood cells. The destruction of these cells may be primarily mediated through an Fc-independent pathway. Fc-independent phagocytosis may also play an important role in platelet clearance, including immune thrombocytopenia (ITP). The two major platelet antigens targeted in ITP are GPIIbIIIa and the GPIb complex. It has been demonstrated that anti-GPIbalpha antibodies, in contrast to anti-GPIIbIIIa, can induce thrombocytopenia in an Fc-independent manner. We further demonstrated in an animal model that intravenous IgG is not able to ameliorate thrombocytopenia caused by most anti-GPIbalpha antibodies, though it is effective in anti-GPIIbIIIa mediated thrombocytopenia. Our data was supported by a recent retrospective study of ITP patients. Therefore, identification of antibody specificity (e.g. anti-GPIIbIIIa (Fc-dependent) versus anti-GPIbalpha (Fc-independent)) in patients may be important for ITP therapy.
Collapse
Affiliation(s)
- Michelle Lee Webster
- Canadian Blood Services and Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital, University of Toronto, 30 Bond Street, Room 2-006, Bond Wing, Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
30
|
Tomiyama Y. [Autoimmune (idiopathic) thrombocytopenic purpura]. Rinsho Ketsueki 2008; 49:1298-1305. [PMID: 18833913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
MESH Headings
- Acute Disease
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Murine-Derived
- Autoantibodies/blood
- Benzoates/therapeutic use
- Biomarkers/blood
- Blood Platelets/immunology
- Chronic Disease
- Female
- Humans
- Hydrazines/therapeutic use
- Immunoglobulin G/blood
- Immunosuppressive Agents/therapeutic use
- Male
- Platelet Glycoprotein GPIIb-IIIa Complex/immunology
- Platelet Glycoprotein GPIb-IX Complex/immunology
- Prednisolone/therapeutic use
- Purpura, Thrombocytopenic, Idiopathic/diagnosis
- Purpura, Thrombocytopenic, Idiopathic/epidemiology
- Purpura, Thrombocytopenic, Idiopathic/physiopathology
- Purpura, Thrombocytopenic, Idiopathic/therapy
- Pyrazoles/therapeutic use
- Rituximab
- Splenectomy
Collapse
|
31
|
Fontayne A, Meiring M, Lamprecht S, Roodt J, Demarsin E, Barbeaux P, Deckmyn H. The humanized anti-glycoprotein Ib monoclonal antibody h6B4-Fab is a potent and safe antithrombotic in a high shear arterial thrombosis model in baboons. Thromb Haemost 2008; 100:670-677. [PMID: 18841291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The Fab-fragment of 6B4, a murine monoclonal antibody targeting the human platelet glycoprotein (GP) Ibalpha and blocking the binding of von Willebrand factor (VWF), is a powerful antithrombotic. In baboons, this was without side effects such as bleeding or thrombocytopenia. Recently, we developed a fully recombinant and humanized version of 6B4-Fab-fragment, h6B4-Fab, which maintains its inhibitory capacities in vitro and ex vivo after injection in baboons. We here investigated the antithrombotic properties, the effect on bleeding time and blood loss and initial pharmacokinetics of h6B4-Fab in baboons. The antithrombotic effect of h6B4-Fab on acute platelet-mediated thrombosis was studied in baboons where thrombus formation is induced at an injured and stenosed site of the femoral artery, allowing for cyclic flow reductions (CFRs) which are measured on an extracorporeal femoral arteriovenous shunt. Injection of 0.5 mg/kg h6B4-Fab significantly reduced the CFRs by 80%, whereas two extra injections, resulting in cumulative doses of 1.5 and 2.5 mg/kg, completely inhibited the CFRs. Platelet receptor occupancy, plasma concentrations and effects ex vivo were consistent with what was previously observed. Finally, minimal effects on bleeding time and blood loss, no spontaneous bleeding and no thrombocytopenia were observed. We therefore conclude that h6B4-Fab maintains the antithrombotic capacities of the murine 6B4-Fab, without causing side effects and therefore can be used for further development.
Collapse
Affiliation(s)
- Alexandre Fontayne
- Laboratory for Thrombosis Research, IRC, KU Leuven Campus Kortrijk, E. Sabbelaan 53, Kortrijk, Belgium
| | | | | | | | | | | | | |
Collapse
|
32
|
Lei Q, Liu Y, Tang SQ. [Childhood acute megakaryoblastic leukemia]. Zhongguo Shi Yan Xue Ye Xue Za Zhi 2007; 15:528-32. [PMID: 17605859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The aim of this study was to investigate the clinical, pathological and biological features of acute megakaryoblastic leukemia in childhood. The morphology of cells was observed by means of bone marrow smear; the immunophenotype was detected by flow cytometry and immunohistochemistry assay. The results indicated that the fever, hemorrhage, hepatosplenomegaly and lymphadenopathy in this case were the primary presentations accompanying by leukocytosis, anemia and thrombocytopenia. An adequate marrow aspirate could not be obtained. At the time of diagnosis, the bone marrow had more than 30% megakaryoblasts in nucleated cells. Flow cytometric analysis revealed the dual expression of CD41 and CD61 by tumor cells in bone marrow. The histopathological examination of bone marrow demonstrated infiltration of large-sized CD42b(+) cells. According to all above mentioned results, this case was diagnosed as acute megakaryoblastic leukemia. In conclusion, childhood acute megakaryoblastic leukemia is a rare and easily misdiagnosed disease with poor prognosis. Flow cytometry analysis and immunohistochemistry assay of bone marrow can help in detecting this leukemia subtype and evaluating its prognosis.
Collapse
Affiliation(s)
- Qi Lei
- Department of Pediatrics, General Hospital of PLA, Beijing 100853, China
| | | | | |
Collapse
|
33
|
Abstract
Background—
Ischemic stroke is a frequent and serious disease with limited treatment options. Platelets can adhere to hypoxic cerebral endothelial cells by binding of their glycoprotein (GP) Ib receptor to von Willebrand factor. Exposure of subendothelial matrix proteins further facilitates firm attachment of platelets to the vessel wall by binding of collagen to their GPVI receptor. In the present study, we addressed the pathogenic role of GPIb, GPVI, and the aggregation receptor GPIIb/IIIa in experimental stroke in mice.
Methods and Results—
Complete blockade of GPIbα was achieved by intravenous injection of 100 μg Fab fragments of the monoclonal antibody p0p/B to mice undergoing 1 hour of transient middle cerebral artery occlusion. At 24 hours after transient middle cerebral artery occlusion, cerebral infarct volumes were assessed by 2,3,5-triphenyltetrazolium chloride staining. In mice treated with anti-GPIbα Fab 1 hour before middle cerebral artery occlusion, ischemic lesions were reduced to ≈40% compared with controls (28.5±12.7 versus 73.9±17.4 mm
3
, respectively;
P
<0.001). Application of anti-GPIbα Fab 1 hour after middle cerebral artery occlusion likewise reduced brain infarct volumes (24.5±7.7 mm
3
;
P
<0.001) and improved the neurological status. Similarly, depletion of GPVI significantly diminished the infarct volume but to a lesser extent (49.4±19.1 mm
3
;
P
<0.05). Importantly, the disruption of early steps of platelet activation was not accompanied by an increase in bleeding complications as revealed by serial magnetic resonance imaging. In contrast, blockade of the final common pathway of platelet aggregation with anti-GPIIb/IIIa F(ab)
2
fragments had no positive effect on stroke size and functional outcome but increased the incidence of intracerebral hemorrhage and mortality after transient middle cerebral artery occlusion in a dose-dependent manner.
Conclusions—
Our data indicate that the selective blockade of key signaling pathways of platelet adhesion and aggregation has a different impact on stroke outcome and bleeding complications. Inhibition of early steps of platelet adhesion to the ischemic endothelium and the subendothelial matrix may offer a novel and safe treatment strategy in acute stroke.
Collapse
|
34
|
Penz SM, Reininger AJ, Toth O, Deckmyn H, Brandl R, Siess W. Glycoprotein Ibalpha inhibition and ADP receptor antagonists, but not aspirin, reduce platelet thrombus formation in flowing blood exposed to atherosclerotic plaques. Thromb Haemost 2007; 97:435-43. [PMID: 17334511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Anti-platelet drugs are used to prevent intra-arterial thrombus formation after rupture of atherosclerotic plaques. Until now, the inhibitory effect of present and future anti-platelet drugs such as aspirin, ADP receptor P2Y(1)/P2Y(12) antagonists and glycoprotein (GP) Ibalpha inhibitors on the interaction of platelets with human plaques is not known. To study those effects we obtained human atherosclerotic plaques by surgical endarterectomy. Plaques induced maximal platelet aggregation in hirudinized platelet-rich plasma (PRP) and blood that was effectively inhibited by aspirin, the P2Y(1) antagonist MRS2179 and the P2Y(12) antagonist AR-C69931MX, but not by GPIbalpha blockade with the mAB 6B4. Inhibition of platelet aggregation by MRS2179 was 74 +/- 37% and 68 +/- 20%, by AR-C69931MX 94 +/- 7% and 80 +/- 6%, and by aspirin 88 +/- 19% and 64 +/- 28%, in PRP and blood, respectively (mean +/- SD; n = 6-12 with plaques from 6 patients). The combination of both ADP receptor antagonists completely inhibited plaque-induced platelet aggregation in hirudinized PRP and blood. Under arterial flow conditions (1,500s(-1)), blockade of platelet GPIbalpha resulted in a strong decrease of plaque-stimulated platelet adhesion/aggregate formation of 77 +/- 5% (mean +/- SD; n = 4). Furthermore, MRS2179, AR-C69931MX and their combination reduced plaque-dependent platelet aggregate formation by 35 +/- 14%, 32 +/- 13% and 58 +/- 12% (mean +/- SD; n = 5), respectively. Aspirin was without significant effect. In conclusion, a GPIbalpha-blocking antibody, as well as P2Y(1) and P2Y(12) receptor antagonists, alone or in combination, reduce in contrast to aspirin human plaque-induced platelet thrombus formation under arterial flow. Although these new anti-platelet agents inhibit platelet thrombus formation after plaque rupture, more efficient platelet blockers are required.
Collapse
Affiliation(s)
- Sandra M Penz
- Institute for Prevention of Cardiovascular Diseases, University of Munich, Munich, Germany
| | | | | | | | | | | |
Collapse
|
35
|
Wang JD, Pan XL, Yin Z, Sun JH, Kong GX, Chen YJ, Jiang CY, Dou AX, Wang ZL. [Expression of specific antibodies against platelet glycoproteins in patients with mds and its significance]. Zhongguo Shi Yan Xue Ye Xue Za Zhi 2007; 15:95-8. [PMID: 17490530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The aim of this study was to find platelet specific autoantibodies against glycoproteins in myelodysplastic syndrome (MDS) and to explore its role in pathogenesis of MDS. The plasma autoantibodies against GP IIb/IIIa and GP Ib/IX were measured by using a modified monoclonal antibody specific immobolization platelet antigens assay (MAIPA). Absorbance greater than mean value plus tripled standard deviation recorded from the normal controls were regarded as positive. The results indicated that the total positive rate in patients with MDS was 16.67% (5/30), the total positive rate in patients with ITP was 46.67% (14/30), the difference between MDS group and ITP group was significant (P < 0.05). It is concluded that partial patients with MDS have plasma specific autoantibodies against platelet GP II b/III a and GP Ib/IX, indicating correlation of thrombocytopenia of patients with immune factors and the autoantibody-mediated platelet destruction may be involved in the pathogenesis of MDS. It provides a new basis for immunosuppression therapy for MDS.
Collapse
Affiliation(s)
- Juan-Dong Wang
- Department of Hematology, The Second Hospital of Shandong University, Jinan 250033, China
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Pontiggia L, Steiner B, Ulrichts H, Deckmyn H, Forestier M, Beer JH. Platelet microparticle formation and thrombin generation under high shear are effectively suppressed by a monoclonal antibody against GPIba. Thromb Haemost 2006; 96:774-80. [PMID: 17139372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We studied the inhibition of platelet microparticle (MP) formation and thrombin generation under high shear forces. We hypothesized that an inhibitor of the GPIb a -von Willebrand factor (vWF) interaction would be more effective in suppressing MP formation and thrombin generation than GPIIb/IIIa inhibitors. Platelet-rich plasma (PRP) anticoagulated with PPACK (D-Phe-Pro-Arg chloromethyl ketone) was exposed in a cone-and-plate viscometer (shear: 5,000 s(-1) for 5 min) in the presence of antagonists to GPIb a (the monoclonal antibody [Mab] Ib-23) or to GPIIb/IIIa (abciximab, tirofiban, eptifibatide) at their IC90 determined in platelet aggregometry with ristocetin or ADP, respectively. We used double labeling (CD41-PE and annexin-V-FITC) for flow cytometric detection of MP and their aminophospholipid exposure. Thrombin generation was measured using PRP prepared from ACD anticoagulated blood. About 40% of the thrombin generation was found to be mediated by the MP fraction of the PRP. Blockade of GPIb a with Mab Ib-23 reduced MP formation and thrombin generation by 50%, and was more effective than any GPIIb/IIIa antagonist. The combination of Mab Ib-23 with one of the GPIIb/IIIa inhibitors further reduced the MP formation to ~ 30%. The antibody also partially inhibited thrombin induced platelet aggregation. Epitope mapping suggested that Mab Ib-23 binds between the amino acids 201 and 268 of GPIb a , explaining the interference with vWF and thrombin interaction. In contrast to the commonly used GPIIb/IIIa antagonists, the blockade of GPIb a with Mab Ib-23 effectively reduces the prothrombotic MP generation and thrombin formation at shear rates typically found in arterial stenoses.
Collapse
Affiliation(s)
- Luca Pontiggia
- Department of Medicine, Laboratory for Thrombosis Research, Kantonsspital Baden, Switzerland
| | | | | | | | | | | |
Collapse
|
37
|
Abstract
Immune thrombocytopenia induced by quinine and many other drugs is caused by antibodies that bind to platelet membrane glycoproteins (GPs) only when the sensitizing drug is present in soluble form. In this disorder, drug promotes antibody binding to its target without linking covalently to either of the reacting macro-molecules by a mechanism that has not yet been defined. How drug provides the stimulus for production of such antibodies is also unknown. We studied 7 patients who experienced severe thrombocytopenia after ingestion of quinine. As expected, drug-dependent, platelet-reactive antibodies specific for GPIIb/IIIa or GPIb/IX were identified in each case. Unexpectedly, each of 6 patients with GPIIb/IIIa-specific antibodies was found to have a second antibody specific for drug alone that was not platelet reactive. Despite recognizing different targets, the 2 types of antibody were identical in requiring quinine or desmethoxy-quinine (cinchonidine) for reactivity and in failing to react with other structural analogues of quinine. On the basis of these findings and previous observations, a model is proposed to explain drug-dependent binding of antibodies to cellular targets. In addition to having implications for pathogenesis, drug-specific antibodies may provide a surrogate measure of drug sensitivity in patients with drug-induced immune cytopenia.
Collapse
Affiliation(s)
- Daniel W Bougie
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, USA.
| | | | | |
Collapse
|
38
|
Webster ML, Sayeh E, Crow M, Chen P, Nieswandt B, Freedman J, Ni H. Relative efficacy of intravenous immunoglobulin G in ameliorating thrombocytopenia induced by antiplatelet GPIIbIIIa versus GPIbalpha antibodies. Blood 2006; 108:943-6. [PMID: 16861348 DOI: 10.1182/blood-2005-06-009761] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intravenous immunoglobulin G (IVIG) is used to treat idiopathic thrombocytopenic purpura (ITP). Although many patients benefit from IVIG, some are refractory to this therapy. ITP is characterized by platelet clearance mediated primarily by antiplatelet antibodies against GPIIbIIIa and/or the GPIbalpha complex. These 2 groups of antibodies may induce ITP through different mechanisms. We tested the hypothesis that IVIG may not be equally effective in preventing ITP caused by anti-GPIIbIIIa versus anti-GPIbalpha antibodies in mice. Thrombocytopenia was induced in BALB/c mice using monoclonal antibodies against either mouse GPIIbIIIa (JON1, JON2, and JON3) or GPIbalpha (p0p3, p0p4, p0p5, p0p9, and p0p11). Pretreatment with IVIG significantly ameliorated ITP in all anti-GPIIbIIIa-injected animals. Conversely, IVIG failed to prevent ITP in all anti-GPIbalpha-treated mice, except for p0p4. These results were repeated in C57BL/6 mice, and with different IVIG preparations. These data in mice suggest that patients with ITP mediated by anti-GPIbalpha antibodies may be less responsive to IVIG treatment.
Collapse
|
39
|
Hagay Y, Lahav J, Levanon A, Varon D, Brill A, Panet A. Molecular characterization of an human monoclonal antibody that interacts with a sulfated tyrosine-containing epitope of the GPIb receptor and inhibits platelet functions. Mol Immunol 2006; 43:443-53. [PMID: 16337487 DOI: 10.1016/j.molimm.2005.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2004] [Accepted: 03/04/2005] [Indexed: 11/30/2022]
Abstract
Modification of tyrosine residues in extracellular proteins by a sulfate moity plays an important role in many ligand/receptors interactions. In the present work, we describe a unique human monoclonal antibody, termed Y1-scFv, that is specific for a sulfated epitope in the platelat receptor GPIb. The Y1-scFv single chain antibody (scFv) competes with von Willebrand factor (vWF) for binding to human platelets and thus effectively inhibits platelet aggregation. Limited proteolysis of GPIb molecule, using the endoproteases, mocarhagin and cathepsin G, revealed that a seven amino-acid epitope, Tyr-276 to Glu-282, contains the recognition site for Y1-scFv. This GPIb region contains three sulfated tyrosine residues. Binding studies of Y1-scFv to cells and to synthetic peptides in vitro indicated that of the seven residues comprising the epitope only sulfo-Tyr-276 and adjacent Asp-277 are critical for the interaction. To identify the reciprocal sequences in the antibody that recognize the sulfated epitope, we introduced mutations within the complementary-determining region of the heavy chain (CDR3H) of Y1-scFv (MRAPVI). Arginine residue in the second position was critical for the binding. Moreover, a mutant, containing two sequential arginine residues, in the second and third positions of the CDR3H (MRRPVI), showed a nine-fold increased binding to GPIb. This antibody mutant also demonstrated a significant increase in inhibition of vWF-dependent platelet aggregation and adhesion under flow. In conclusion, this unique antibody and mutants, that recognize a sulfated epitope in GP1b receptor, efficiently inhibited platelet adhesion and aggregation, making it a candidate for a new anti-thrombotic agent.
Collapse
Affiliation(s)
- Yocheved Hagay
- Bio-Technology General (Israel) Ltd., Research Department, Kiryat Weizmnn, Building 17, 76326 Rehovot, Israel.
| | | | | | | | | | | |
Collapse
|
40
|
Kunishima S, Motoyama M, Takagi A, Hamaguchi M, Kojima T, Saito H. Further characterization of anti-platelet monoclonal antibody HPL5 as anti-glycoprotein V antibody. Acta Haematol 2006; 115:128-30. [PMID: 16424664 DOI: 10.1159/000089480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 05/17/2005] [Indexed: 11/19/2022]
Affiliation(s)
- Shinji Kunishima
- Department of Hemostasis and Thrombosis, Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya University School of Health Sciences, Nagoya, Japan.
| | | | | | | | | | | |
Collapse
|
41
|
Hauben M, Younus M. Rosiglitazone-induced immune thrombocytopenia. Platelets 2006; 17:591-3. [PMID: 17127488 DOI: 10.1080/09537100600935309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
42
|
Shi T, Giannakopoulos B, Yan X, Yu P, Berndt MC, Andrews RK, Rivera J, Iverson GM, Cockerill KA, Linnik MD, Krilis SA. Anti–β2-glycoprotein I antibodies in complex with β2-glycoprotein I can activate platelets in a dysregulated manner via glycoprotein Ib-IX-V. ACTA ACUST UNITED AC 2006; 54:2558-67. [PMID: 16868978 DOI: 10.1002/art.21968] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Results of previous studies suggest that anti-beta2-glycoprotein I (anti-beta2GPI) antibodies in complex with beta2GPI activate platelets in a dysregulated manner, potentially contributing to the prothrombotic tendency associated with the antiphospholipid syndrome (APS). We undertook this study to investigate the possible contribution of the GPIb-IX-V receptor to platelet activation mediated by the anti-beta2GPI antibody-beta2GPI complex. METHODS In vitro methods were used in the present study. The interaction between beta2GPI and the GPIbalpha subunit of the GPIb-IX-V receptor was delineated using direct binding and competitive inhibition assays. The interaction between the anti-beta2GPI antibody-beta2GPI complex and platelets was studied using a novel method in which the Fc portion of the antibody was immobilized using protein A coated onto a microtiter plate. Platelet activation was assessed by two methods; one involved measuring thromboxane B2 production and the other involved assessment of the activation of the phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase 3beta intracellular signaling pathway. The contribution of the GPIbalpha receptor to platelet activation induced by the anti-beta2GPI antibody-beta2GPI complex was assessed by observing the influence of 2 anti-GPIbalpha antibodies (AK2 and SZ2) directed against distinct epitopes. RESULTS This study showed that beta(2)GPI could bind to the GPIbalpha receptor. The anti-beta2GPI antibody-beta2GPI complex was able to activate platelets, and this effect was inhibited by anti-GPIbalpha antibody directed against epitope Leu-36-Gln-59, but not by anti-GPIbalpha antibody directed against residues Tyr-276-Glu-282. CONCLUSION Our findings show that inappropriate platelet activation by the anti-beta2GPI antibody-beta2GPI complex via the GPIbalpha receptor may contribute to the prothrombotic tendency associated with APS.
Collapse
Affiliation(s)
- Tong Shi
- St. George Hospital, University of New South Wales, Sydney, New South Wales, Australia
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Chu XX, Hou M, Zhu YY, Peng J, Ji XB, Zhang F, Wang L. [Identification of human platelet specific functional antibody and its fragments]. Zhonghua Yi Xue Za Zhi 2005; 85:3464-8. [PMID: 16686061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
OBJECTIVE To study the immunoreactivity of the specific anti-platelet glycoprotein (GP) IgG antibody and its F(ab')2 fragments from patients with chronic idiopathic thrombocytopenic purpura (ITP) and to investigate their effects on platelet aggregation function. METHODS Peripheral blood samples were collected from 84 patients with ITP. Modified monoclonal antibody immobilization of platelet antigen assays was used to detect the IgG antibodies specific for GP I b/II a, GP I b/IX and GP VI. The IgG antibody and its F(ab')2 fragments in the positive plasma inhibiting platelet aggregation function were prepared and purified. Plate-rich Peripheral blood sample was collected from a normal person with O type blood and platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were prepared. Plasma pf ITP patient or purified IgG or F(ab')2 fragments of different concentrations were added into PRP, and then inducers of platelet aggregation ADP, ristocetin, or collagen were added. The platelet aggregation was measured. Platelet GP II b/III a specific human-rat chimeric antibody 7E3 and GP I b specific antibody SZ2 were used as positive controls and PBS was used as negative control. RESULTS GP II b/III a and/or GP I b/IX and/or GP VI specific antibodies were found in 48 (57.1%) patients. The plasma, purified IgG and F(ab')2 fragments of 7 of these 48 patients (14.6%) with positive autoantibody showed significant activity against GP II b/III a (4 patients), GP I b/IX (2 patients), or GP VI (one patient). The purified IgG and F(ab')2 fragments of 2 patients positive in GP II b/ III a autoantibody out of the 7 patients significantly inhibited the platelet aggregation induced by ADP, the purified IgG and F(ab')2 fragments of 1 patients positive in GP I b/IX out of the 7 patients significantly inhibited the platelet aggregation induced by ristocetin, and the purified IgG and F(ab')2 fragments of 1 patients positive in GP VI out of the 7 patients significantly inhibited the platelet aggregation induced by collagen. CONCLUSION A functional fragment, F(ab')2 portion of IgG is responsible for the autoantibody interaction with platelet GPs in ITP, and some of them also affect the platelet function. It can be used to develop completely humanized anti-GP small molecular phage antibody.
Collapse
Affiliation(s)
- Xiao-xia Chu
- Department of Hematology Qilu Hospital of Shandong University, Jinan 250012, China
| | | | | | | | | | | | | |
Collapse
|
44
|
Peterson JA, Balthazor SM, Curtis BR, McFarland JG, Aster RH. Maternal alloimmunization against the rare platelet-specific antigen HPA-9b (Max a) is an important cause of neonatal alloimmune thrombocytopenia. Transfusion 2005; 45:1487-95. [PMID: 16131382 PMCID: PMC1602180 DOI: 10.1111/j.1537-2995.2005.00561.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Neonatal alloimmune thrombocytopenia (NATP) is an important cause of morbidity and mortality in the newborn. Optimal management of subsequent pregnancies requires knowledge of the alloantigen that caused maternal immunization, but this is possible only in a minority of cases. This study investigated whether this can be explained in part by maternal immunization against the "rare" alloantigen HPA-9b (Max(a)), implicated previously only in a single NATP case. STUDY DESIGN AND METHODS Archived paternal DNA from unresolved cases of NATP and normal individuals was typed for platelet (PLT)-specific antigens with real-time polymerase chain reaction and direct sequencing. PLT-specific alloantibodies were characterized by flow cytometry and solid-phase enzyme-linked immunosorbent assay. Recombinant GPIIb/IIIa was expressed in stably transfected Chinese hamster ovary cells. Clinical information was obtained directly from attending physicians. RESULTS Six of 217 fathers were positive for the presence of HPA-9b (Max(a)), an incidence about seven times that in the general population. In each of five cases studied, maternal serum samples reacted with intact paternal PLTs and paternal GPIIb/IIIa. Only one of three serum samples tested recognized recombinant GPIIb/IIIa carrying the HPA-9b (Max(a)) mutation. These seemingly discrepant reactions may reflect different requirements for oligosaccharides linked to residues close to the mutation in GPIIb that determines HPA-9b (Max(a)). NATP in the affected children was severe and was associated with intracranial hemorrhage in three of six infants on whom information was obtained. CONCLUSIONS Maternal immunization against HPA-9b (Max(a)) is an important cause of NATP and should be considered in cases of apparent NATP not resolved on the basis of maternal-fetal incompatibility for "common" PLT antigens.
Collapse
Affiliation(s)
- Julie A Peterson
- The Blood Research Institute, The BloodCenter of Wisconsin, 8727 Watertown Plank Road, Wauwatosa, WI 53226, USA.
| | | | | | | | | |
Collapse
|
45
|
Chu XX, Hou M. [Advances in the studies of humanized anti-platelet antibody--review]. Zhongguo Shi Yan Xue Ye Xue Za Zhi 2005; 13:915-7. [PMID: 16277871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Platelet plays an important role in bleeding and thrombotic diseases. Humanized anti-platelet antibodies have great clinical effects in treatment of ITP and preventing thrombosis. The important role of platelet in bleeding and thrombotic diseases, the present status of development on study of humanized anti-platelet antibody and its application in treatment of bleeding and thrombotic diseases were summarized in this review.
Collapse
Affiliation(s)
- Xiao-Xia Chu
- Department of Hematology, Qilu Hospital of Shandong University, Jinan 250012, China
| | | |
Collapse
|
46
|
Hopkins LM, Davis JM, Buchli R, Vangundy RS, Schwartz KA, Gerlach JA. MHC Class I–Associated Peptides Identified From Normal Platelets and From Individuals With Idiopathic Thrombocytopenic Purpura. Hum Immunol 2005; 66:874-83. [PMID: 16216671 DOI: 10.1016/j.humimm.2005.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Indexed: 11/22/2022]
Abstract
Major histocompatibility complex (MHC) class I molecules bind and display peptide antigens on the cell surface. CD8(+) T lymphocytes recognize peptides in association with class I proteins to initiate a cytotoxic immune response. To understand the specificity of such immune responses and to facilitate the development of therapies for disease, it is important to identify MHC-presented peptides. In this study, platelets, easily obtainable and often associated with immune-mediated disease, were selected to identify MHC class I-associated peptides. MHC-associated peptides presented on platelets of normal individuals and individuals with idiopathic thrombocytopenic purpura (ITP) were characterized. ITP is characterized by the premature immune destruction of platelets. It is associated with the production of antiplatelet autoantibodies, most often targeting platelet membrane GPIIb/IIIa or GPIb/IX. In addition to characterizing five fully and several partially sequenced peptides from platelets, the peptide GPRGA(L/I)S(L/I)(L/I) was identified from four of the five ITP patients. The anchor motif of this peptide correlates with the presence of the HLA-B7 allele. A BLAST search identified this peptide as GPIb (4-12). In conclusion, platelets from normal and ITP individuals can present peptides from general cellular proteins and platelet specific proteins, such as GPIb, to the immune system via MHC class I.
Collapse
Affiliation(s)
- Leann M Hopkins
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI, USA
| | | | | | | | | | | |
Collapse
|
47
|
Mandelbaum M, Koren D, Eichelberger B, Auerbach L, Panzer S. Frequencies of maternal platelet alloantibodies and autoantibodies in suspected fetal/neonatal alloimmune thrombocytopenia, with emphasis on human platelet antigen-15 alloimmunization. Vox Sang 2005; 89:39-43. [PMID: 15938738 DOI: 10.1111/j.1423-0410.2005.00662.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVES Serological evaluation of maternal sera for platelet antibodies in suspected fetal/neonatal alloimmune thrombocytopenia (FNAITP) discloses in only approximately 30% of individuals a platelet-specific antibody. Transfusion-induced alloimmunization against human platelet antigen-15 (HPA-15) has been reported to be about as common as against HPA-5, the second most common platelet antibody. Thus, anti-HPA-15 may also contribute significantly to yet-unclear cases of FNAITP. MATERIALS AND METHODS In this retrospective analysis, we provide data on maternal platelet antibodies from 309 mothers who delivered an offspring with suspected FNAITP. RESULTS Genotyping maternal and paternal samples (together n = 573) revealed a gene frequency of 0.496 for HPA-15a and a gene frequency of 0.504 for HPA-15b. HPA-15 antibodies were detected in 2% of all samples. Anti-HPA-15a and -15b were detected in two and three samples, respectively. One serum reacted equally with HPA-15a and -15b platelets. The most frequent platelet-specific antibodies were anti-HPA-1a (22%), but anti-HPA-5b (8.4%) were more frequent than anti-HPA-15. In addition, panreactive (5.5%) or autoreactive (5.2%) anti-GPIIb/IIIa or anti-GPIb/IX were detectable in maternal samples. CONCLUSIONS These data indicate that HPA-15 alloimmunization needs only to be considered in subjects with suspected FNAITP if no other platelet-specific antibody is detectable. The presence of panreactive or autoreactive antibodies should also be considered in neonatal thrombocytopenia.
Collapse
Affiliation(s)
- M Mandelbaum
- Clinic for Blood Group Serology, Medical University Vienna, Vienna, Austria
| | | | | | | | | |
Collapse
|
48
|
Deckmyn H, Cauwenberghs N, Wu D, Depraetere H, Vanhoorelbeke K. Development of antibodies that interfere with the collagen-VWF-GPIb axis as new antithrombotics. Verh K Acad Geneeskd Belg 2005; 67:55-65. [PMID: 15828307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The epitope and the antithrombotic effect of 6B4, an antibody that inhibits GPIb, the receptor for von Willebrand Factor (VWF) on blood platelets, and of 82D6A3, an antibody against VWF that prevents the binding of VWF to collagen, were characterised. By using canine-human chimeras, alanine-scans, phage display, mutant analysis and modeling both the epitope of 6B4 in the N-terminal domain of GPIb, and of 82D6A3 in the VWF-A3 domain, could be mapped. As both epitopes furthermore are part of the ligand binding sites, this at once also explained the mechanism of the inhibition by the antibodies. Next both antibodies were tested in a thrombosis model in a stenosed artery in baboons, where they showed potent antithrombotic activities, without a noteworthy prolongation of the bleeding time. With this we thus could reveal two new strategies to prevent arterial thrombosis, which presumably may be safer than the currently available antiplatelet agents.
Collapse
Affiliation(s)
- H Deckmyn
- Laboratory for Thrombosis Research, KULeuven Campus Kortrijk, Interdisciplinary Research Center, E. Sabbelaan 53--B 8500 Kortrijk
| | | | | | | | | |
Collapse
|
49
|
Grossjohann B, Eichler P, Greinacher A, Santoso S, Kroll H. Ceftriaxone causes drug-induced immune thrombocytopenia and hemolytic anemia: characterization of targets on platelets and red blood cells. Transfusion 2004; 44:1033-40. [PMID: 15225244 DOI: 10.1111/j.1537-2995.2004.03378.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ceftriaxone, a third-generation cephalosporin, has been reported to occasionally cause fatal drug-induced immune hemolytic anemia (DIHA). A clinical and serologic analysis of the first two patients with severe drug-induced thrombocytopenia (DITP) due to ceftriaxone and one patient with fatal DIHA is reported. STUDY DESIGN AND METHODS Sera were assessed by the IAT, EIA, glycoprotein (GP)-specific immunoassay, flow cytometry, and immunoprecipitation using transfectants expressing GPIIb/IIIa and GPIb/IX and with different cephalosporins. RESULTS Sera from Patients 1 and 2 reacted strongly with PLTs in the presence of the drug, but not with RBCs. The binding sites of the drug-dependent antibodies (DDAbs) could be localized to GPIIb/IIIa and GPIb/IX, respectively. Inhibition studies indicated that DDAbs recognized epitopes residing on the GPIIb/IIIa complex and on the GPIX subunit, respectively. No cross-reactivity was observed with other cephalosporin derivatives. Serum 3 showed strong agglutination with RBCs of Rh(null) phenotype in the presence of ex-vivo metabolites of ceftriaxone, but no cross-reactivity with PLTs. CONCLUSIONS The first two cases of severe DITP and a third patient with DIHA are reported. DDAbs from all patients showed individual reaction patterns and clear cell lineage specificity. In addition, the DDAbs were dependent on the substitution at position 3 of the ceftriaxone molecule. Epitopes on GPIIb/IIIa and GPIX were involved on PLTs. The Rh protein was not the only target of DDAbs on RBCs.
Collapse
Affiliation(s)
- Beatrice Grossjohann
- Institute for Immunology and Transfusion Medicine, Ernst Moritz Arndt University Greifswald, Germany
| | | | | | | | | |
Collapse
|
50
|
Fabris F, Scandellari R, Ruzzon E, Randi ML, Luzzatto G, Girolami A. Platelet-associated autoantibodies as detected by a solid-phase modified antigen capture ELISA test (MACE) are a useful prognostic factor in idiopathic thrombocytopenic purpura. Blood 2004; 103:4562-4. [PMID: 14976036 DOI: 10.1182/blood-2003-09-3352] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There were 50 consecutive idiopathic thrombocytopenic purpura (ITP) adult patients (platelet count < 100 x 10(9)/L) grouped according to positivity or negativity of a solid-phase modified antigen capture enzyme-linked immunosorbent assay (ELISA) test (MACE) against glycoprotein IIb/IIIa (GPIIb/IIIa), Ib/IX, and IIa/IIIa. Observation started on the day of MACE assay and lasted at least 6 months. Clinical worsening was defined as the need for starting or modifying therapy because of thrombocytopenia lower than 20 x 10(9)/L or patient admission due to bleeding symptoms. MACE-positive patients had a higher probability of clinical worsening than MACE-negatives (P <.004). The proportion of patients worsening was 18 (72%) of 25 among MACE-positives and 8 (32%) of 25 among MACE-negatives. The median time to clinical worsening was 2.1 months for MACE-positive patients and 27.7 months for MACE-negatives. The assay of specific platelet autoantibodies may be a useful prognostic tool for the clinical course of ITP.
Collapse
Affiliation(s)
- Fabrizio Fabris
- Department of Medical and Surgical Sciences, University of Padua Medical School, via Ospedale 105, 35128 Padua, Italy.
| | | | | | | | | | | |
Collapse
|