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Cruz-Leal Y, Norris PAA, Gil Gonzalez L, Marjoram D, Wabnitz H, Shan Y, Lazarus AH. Trogocytosis drives red blood cell antigen loss in association with antibody-mediated immune suppression. Blood 2024; 143:807-821. [PMID: 37946269 DOI: 10.1182/blood.2023020860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/27/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023] Open
Abstract
ABSTRACT Red blood cell (RBC) alloimmunization to paternal antigens during pregnancy can cause hemolytic disease of the fetus and newborn (HDFN). This severe and potentially fatal neonatal disorder can be prevented by the administration of polyclonal anti-D through a mechanism referred to as antibody-mediated immune suppression (AMIS). Although anti-D prophylaxis effectively prevents HDFN, a lack of mechanistic clarity has hampered its replacement with recombinant agents. The major theories behind AMIS induction in the hematologic literature have classically centered around RBC clearance; however, antigen modulation/loss has recently been proposed as a potential mechanism of AMIS. To explore the primary mechanisms of AMIS, we studied the ability of 11 different antibodies to induce AMIS, RBC clearance, antigen loss, and RBC membrane loss in the HOD (hen egg lysozyme-ovalbumin-human Duffy) murine model. Antibodies targeting different portions of the HOD molecule could induce AMIS independent of their ability to clear RBCs; however, all antibodies capable of inducing a strong AMIS effect also caused significant in vivo loss of the HOD antigen in conjunction with RBC membrane loss. In vitro studies of AMIS-inducing antibodies demonstrated simultaneous RBC antigen and membrane loss, which was mediated by macrophages. Confocal live-cell microscopy revealed that AMIS-inducing antibodies triggered RBC membrane transfer to macrophages, consistent with trogocytosis. Furthermore, anti-D itself can induce trogocytosis even at low concentrations, when phagocytosis is minimal or absent. In view of these findings, we propose trogocytosis as a mechanism of AMIS induction.
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Affiliation(s)
- Yoelys Cruz-Leal
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Peter A A Norris
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Medicine Huddinge, Center for Hematology and Regenerative Medicine, Karolinska Institute, Stockholm, Sweden
| | - Lazaro Gil Gonzalez
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Danielle Marjoram
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Hanna Wabnitz
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Yuexin Shan
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Alan H Lazarus
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
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2
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Raymond C, Grant B, Zahner C. A Case of Massive Fetal-Maternal Hemorrhage: Lessons Learned in Diagnosis and Treatment. Lab Med 2023; 54:333-336. [PMID: 36315004 DOI: 10.1093/labmed/lmac116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
The use of Rho(D) immune globulin in Rh-negative pregnant women has become standard of care, but many practicing clinicians do not know the dosing recommendations for this essential medication. In this article, we describe a case of a 15-year-old girl who presented with intrauterine fetal demise and was found to have massive fetomaternal hemorrhage. Kleihauer-Betke testing results indicated nearly 460 mL of fetal blood in the maternal circulation. The patient ultimately received 4800 µg of Rho(D) immune globulin, a dose that required close coordination with the obstetrical service and pharmacy. Although this is an unusual case of large-volume, potentially chronic, fetomaternal hemorrhage, it is also an excellent illustration of the principles for diagnosing this condition, as well as providing dosing guidelines for Rho(D) immunoglobulin to prevent alloimmunization.
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Affiliation(s)
- Caitlin Raymond
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Bradley Grant
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Christopher Zahner
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
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3
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Aggregates in blood filter chambers used from the plasma donations of anti-D donors: evaluation for monoclonal antibody discovery using phage display. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2020; 19:64-72. [PMID: 33085594 DOI: 10.2450/2020.0093-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/17/2020] [Indexed: 12/29/2022]
Abstract
BACKGROUND RhD-immunoglobulin (RhIg) prevents anti-D alloimmunisation in D-negative pregnant women when the fetus is D-positive, reducing the incidence of haemolytic disease of the fetus and newborn. Manufacturing RhIg is reliant on the limited supply of plasma donations with anti-D antibodies. Monoclonal antibody (mAb) development platforms such as phage display, require blood samples to be collected from anti-D donors, which may be a complicated process. The blood filter chamber (BFC) discarded after an anti-D donor's donation might provide a source of Ig-encoding RNA. This study aims to evaluate whether used BFCs are a suitable source of Ig-encoding RNA for phage display. MATERIAL AND METHODS Haemonetics PCS2 BFCs were obtained from 10 anti-D donors for total RNA extraction, cDNA synthesis and amplification of VH and VL IgG sequences for assembly of single-chain variable fragments (scFvs). A scFv-phage display library was constructed and 3 rounds of biopanning were performed using D-positive and D-negative red blood cells (RBCs). Positive phage clones were isolated, Sanger sequenced and, where possible, reformatted into full-length human IgGs to define specificity. The BFC aggregates from 2 anti-D donors underwent a Wright-Giemsa stain and hematological cell count. RESULTS Of 10 BFCs, a sufficient yield of total RNA for library construction was obtained from BFCs containing cellular aggregates (n=5). Aggregate analysis showed lymphocytes were the cellular source of Ig-encoding RNA. From the 5 samples with aggregates, scFvs were assembled from amplified IgG variable regions. The library constructed from 1 of these samples resulted in the isolation of clones binding to D-positive RBCs with IGHV3 gene usage. Of the 4 reformatted IgG, 3 were anti-D and 1 had undefined specificity. DISCUSSION BFC aggregates are a new and convenient source of Ig-encoding RNA which can be used to construct Ig gene libraries for mAb isolation and discovery via antibody phage display.
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4
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Mener A, Patel SR, Arthur CM, Stowell SR. Antibody-mediated immunosuppression can result from RBC antigen loss independent of Fcγ receptors in mice. Transfusion 2018; 59:371-384. [PMID: 30474857 DOI: 10.1111/trf.14939] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/17/2018] [Accepted: 05/23/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Anti-RhD administration can prevent de novo anti-RhD formation following RhD+ red blood cell (RBC) exposure, termed antibody-mediated immunosuppression (AMIS). Recent studies suggest that AMIS may occur through target antigen alterations, known as antigen modulation. However, studies suggest that AMIS may occur independent of antigen modulation. In particular, AMIS to RBCs that transgenically express the fusion hen egg lysozyme-ovalbumin-Duffy (HOD) antigen have been shown to occur independent of activating Fcγ receptors (FcγRs) thought to be required for antigen modulation. Therefore, we sought to determine the mechanism behind AMIS following HOD RBC exposure. STUDY DESIGN AND METHODS Following transfer of HOD RBCs into wild-type or FcγR-chain knockout recipients in the presence or absence of monoclonal anti-hen egg lysozyme (HEL) antibody, individually or in combination, HOD antigen levels and anti-HOD antibody formation were examined. RESULTS Our results demonstrate that anti-HEL antibodies individually or in combination suppressed anti-HOD IgM, which correlated with the rate of detectable decrease in HEL on HOD RBCs. Furthermore, exposure to anti-HEL antibodies alone or in combination equally suppressed anti-HOD IgG formation. Unexpectedly, combination or individual anti-HEL antibodies induced AMIS and antigen modulation in an FcγR-independent manner. Pre-exposure of HOD RBCs to anti-HEL antibodies reduced antigen levels and suppressed anti-HOD antibody formation following HOD RBC exposure. CONCLUSION These results suggest that antibody-mediated antigen modulation may reflect a mechanism of AMIS that can occur independent of activating FcγRs and may provide a surrogate to identify antibodies capable of inducing AMIS against different RBC antigens.
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Affiliation(s)
- Amanda Mener
- Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University School of Medicine, Atlanta, Georgia
| | - Seema R Patel
- Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University School of Medicine, Atlanta, Georgia
| | - Connie M Arthur
- Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University School of Medicine, Atlanta, Georgia
| | - Sean R Stowell
- Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University School of Medicine, Atlanta, Georgia
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5
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Maier CL, Mener A, Patel SR, Jajosky RP, Bennett AL, Arthur CM, Hendrickson JE, Stowell SR. Antibody-mediated immune suppression by antigen modulation is antigen-specific. Blood Adv 2018; 2:2986-3000. [PMID: 30413434 PMCID: PMC6234375 DOI: 10.1182/bloodadvances.2018018408] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 09/16/2018] [Indexed: 01/22/2023] Open
Abstract
Alloantibodies developing after exposure to red blood cell (RBC) alloantigens can complicate pregnancy and transfusion therapy. The only method currently available to actively inhibit RBC alloantibody formation is administration of antigen-specific antibodies, a phenomenon termed antibody-mediated immune suppression (AMIS). A well-known example of AMIS is RhD immune globulin prophylaxis to prevent anti-D formation in RhD- individuals. However, whether AMIS is specific or impacts alloimmunization to other antigens on the same RBC remains unclear. To evaluate the specificity of AMIS, we passively immunized antigen-negative recipients with anti-KEL or anti-hen egg lysozyme (HEL) antibodies, followed by transfusion of murine RBC expressing both the HEL-ovalbumin-Duffy (HOD) and human KEL antigens (HOD × KEL RBC). Significant immunoglobulin G deposition on transfused HOD × KEL RBC occurred in all passively immunized recipients. Complement deposition and antigen modulation of the KEL antigen occurred on transfused RBC only in anti-KEL-treated recipients, whereas HEL antigen levels decreased only in the presence of anti-HEL antibodies. Western blot analysis confirmed the specificity of antigen loss, which was not attributable to RBC endocytosis and appears distinct for the 2 antigens. Specifically, removal of KEL was attenuated by clodronate treatment, whereas loss of HEL was unaffected by clodronate in vivo but sensitive to protease treatment in vitro. Antigen-specific modulation correlated with antigen-specific AMIS, with anti-KEL treated recipients forming antibodies to the HOD antigen and anti-HEL-treated recipients developing antibodies to the KEL antigen. Together, these results demonstrate that passively administered antibodies can selectively inhibit the immune response to a specific antigen.
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Affiliation(s)
- Cheryl L Maier
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
| | - Amanda Mener
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
| | - Seema R Patel
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
| | - Ryan P Jajosky
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
| | - Ashley L Bennett
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
| | - Connie M Arthur
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
| | - Jeanne E Hendrickson
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT
| | - Sean R Stowell
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA; and
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6
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Luo J, Lindstrom J. Acetylcholine receptor-specific immunosuppressive therapy of experimental autoimmune myasthenia gravis and myasthenia gravis. Ann N Y Acad Sci 2018; 1413:76-81. [PMID: 29377167 DOI: 10.1111/nyas.13550] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 12/14/2022]
Abstract
Experimental autoimmune myasthenia gravis (EAMG) and myasthenia gravis (MG) are caused by autoantibodies to the extracellular domain of muscle nicotinic acetylcholine receptors (AChRs). Autoantibodies to the cytoplasmic domain of AChRs do not cause EAMG because they cannot bind AChRs in vivo. The ideal MG therapy would quickly and permanently suppress only the pathological autoimmune response to AChRs. We have developed a specific immunosuppressive therapy for EAMG that involves immunizing rats with bacterially expressed cytoplasmic domains of human muscle AChRs. Therapy prevents onset of chronic EAMG, rapidly suppresses ongoing EAMG, and is potent, robust, long lasting, and safe, because the therapeutic antigen cannot induce EAMG. The therapy was developed using incomplete Freund's adjuvant, but is likely to work equally well with alum adjuvants routinely used for human immunizations. Therapeutic mechanisms may involve a combination of antibody-mediated feedback suppression and regulatory T and/or B lymphocytes.
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Affiliation(s)
- Jie Luo
- Department of Clinical Sciences and Advanced Medicine, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania
| | - Jon Lindstrom
- Department of Neuroscience, Medical School of the University of Pennsylvania, Philadelphia, Pennsylvania
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7
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Cruz-Leal Y, Marjoram D, Lazarus AH. Erythrocyte Saturation with IgG Is Required for Inducing Antibody-Mediated Immune Suppression and Impacts Both Erythrocyte Clearance and Antigen-Modulation Mechanisms. THE JOURNAL OF IMMUNOLOGY 2018; 200:1295-1305. [PMID: 29358275 DOI: 10.4049/jimmunol.1700874] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 12/04/2017] [Indexed: 12/21/2022]
Abstract
Anti-D prevents hemolytic disease of the fetus and newborn, and this mechanism has been referred to as Ab-mediated immune suppression (AMIS). Anti-D, as well as other polyclonal AMIS-inducing Abs, most often induce both epitope masking and erythrocyte clearance mechanisms. We have previously observed that some Abs that successfully induce AMIS effects could be split into those that mediate epitope masking versus those that induce erythrocyte clearance, allowing the ability to analyze these mechanisms separately. In addition, AMIS-inducing activity has recently been shown to induce Ag modulation (Ag loss from the erythrocyte surface). To assess these mechanisms, we immunized mice with transgenic murine RBCs expressing a single Ag protein comprising a recombinant Ag composed of hen egg lysozyme, OVA sequences comprising aa 251-349, and the human Duffy transmembrane protein (HOD-Ag) with serial doses of polyclonal anti-OVA IgG as the AMIS-inducing Ab. The anti-OVA Ab induced AMIS in the absence of apparent epitope masking. AMIS occurred only when the erythrocytes appeared saturated with IgG. This Ab was capable of inducing HOD-RBC clearance, as well as loss of the OVA epitope at doses of Ab that caused AMIS effects. HOD-RBCs also lost reactivity with Abs specific for the hen egg lysozyme and Duffy portions of the Ag consistent with the initiation of Ag modulation and/or trogocytosis mechanisms. These data support the concept that an AMIS-inducing Ab that does not cause epitope masking can induce AMIS effects in a manner consistent with RBC clearance and/or Ag modulation.
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Affiliation(s)
- Yoelys Cruz-Leal
- Department of Laboratory Medicine and the Keenan Research Centre for Biomedical Science in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada.,Centre for Innovation, Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada
| | - Danielle Marjoram
- Department of Laboratory Medicine and the Keenan Research Centre for Biomedical Science in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - Alan H Lazarus
- Department of Laboratory Medicine and the Keenan Research Centre for Biomedical Science in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; .,Centre for Innovation, Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario M5G 2C4, Canada; and.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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8
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9
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Cure P, Bembea M, Chou S, Doctor A, Eder A, Hendrickson J, Josephson CD, Mast AE, Savage W, Sola-Visner M, Spinella P, Stanworth S, Steiner M, Mondoro T, Zou S, Levy C, Waclawiw M, El Kassar N, Glynn S, Luban NLC. 2016 proceedings of the National Heart, Lung, and Blood Institute's scientific priorities in pediatric transfusion medicine. Transfusion 2017; 57:1568-1581. [PMID: 28369923 DOI: 10.1111/trf.14100] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/30/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Pablo Cure
- Division of Blood Diseases and Resources, National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | - Melania Bembea
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Hospital, Baltimore, Maryland
| | - Stella Chou
- Department of Hematology and the Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Allan Doctor
- Department of Pediatrics, St Louis Children's Hospital, St Louis, Missouri
| | - Anne Eder
- National Institutes of Health, Bethesda, Maryland
| | - Jeanne Hendrickson
- Department of Laboratory Medicine, Yale University, New Haven, Connecticut
| | | | - Alan E Mast
- Blood Research Institute, Blood Center of Wisconsin, and the Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | | | - Martha Sola-Visner
- Department of Newborn Medicine, Children's Hospital, Boston, Massachusetts
| | | | - Simon Stanworth
- NHS Blood and Transplant, John Radcliffe Hospital, and Oxford Clinical Research in Transfusion Medicine, Nuffield Division of Clinical Laboratory Sciences, University of Oxford, Oxford, UK
| | - Marie Steiner
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | | | - Shimian Zou
- Division of Blood Diseases and Resources, NHLBI/NIH
| | | | - Myron Waclawiw
- National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | | | - Simone Glynn
- Division of Blood Diseases and Resources, NHLBI/NIH
| | - Naomi L C Luban
- Division of Laboratory Medicine, Children's National Health System, Washington, DC
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10
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RhIg-prophylaxis is not influenced by FCGR2/3 polymorphisms involved in red blood cell clearance. Blood 2017; 129:1045-1048. [PMID: 28082442 DOI: 10.1182/blood-2016-05-716365] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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11
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Marjoram D, Cruz-Leal Y, Bernardo L, Lazarus AH. A role for red cell clearance in antibody-mediated inhibition of erythrocyte alloimmunization? ACTA ACUST UNITED AC 2016. [DOI: 10.1111/voxs.12320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- D. Marjoram
- Department of Laboratory Medicine; Keenan Research Centre; Li Ka Shing Knowledge Institute; St. Michael's Hospital; Toronto ON Canada
- Department of Medicine and Laboratory Medicine and Pathobiology; University of Toronto; Toronto ON Canada
| | - Y. Cruz-Leal
- Department of Laboratory Medicine; Keenan Research Centre; Li Ka Shing Knowledge Institute; St. Michael's Hospital; Toronto ON Canada
| | - L. Bernardo
- Department of Laboratory Medicine; Keenan Research Centre; Li Ka Shing Knowledge Institute; St. Michael's Hospital; Toronto ON Canada
- The Canadian Blood Services; Toronto ON Canada
| | - A. H. Lazarus
- Department of Laboratory Medicine; Keenan Research Centre; Li Ka Shing Knowledge Institute; St. Michael's Hospital; Toronto ON Canada
- Department of Medicine and Laboratory Medicine and Pathobiology; University of Toronto; Toronto ON Canada
- The Canadian Blood Services; Toronto ON Canada
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12
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13
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Luo J, Lindstrom J. Antigen-specific immunotherapeutic vaccine for experimental autoimmune myasthenia gravis. THE JOURNAL OF IMMUNOLOGY 2014; 193:5044-55. [PMID: 25288571 DOI: 10.4049/jimmunol.1401392] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Myasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are caused by Ab-mediated autoimmune responses to muscle nicotinic acetylcholine receptors (AChRs) that impair neuromuscular transmission, thereby causing muscle weakness. Previously, we discovered that i.p. injection of a therapeutic vaccine consisting of bacterially expressed cytoplasmic domains of human AChR subunits reduced the development of chronic EAMG in rats. In this article, we show that immunization with the therapeutic vaccine in adjuvants does not induce EAMG and, thus, is safe. The potency and efficacy of the therapeutic vaccine were greatly increased by s.c. administration of repeated low doses in IFA. Onset of chronic EAMG could be prevented. Established chronic EAMG could be rapidly reversed, modeling therapy of chronic MG. Therapy reduced pathological Abs assayed by immune precipitation of a main immunogenic region chimera. Successfully treated rats exhibited long-term resistance to reinduction of EAMG, suggesting a lasting cure of MG. A long-term effect of therapy was to change the isotype of the pathogenic Ab response from IgG2b, which fixes complement, to IgG1, which does not. Prevention and reversal of chronic EAMG was not caused by the isotype switch, but the isotype switch may contribute to resistance to reinduction of EAMG. Immunization with AChR cytoplasmic domains in adjuvant is promising as a safe, Ag-specific, potent, effective, rapidly acting, and long-lasting therapeutic approach to MG.
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Affiliation(s)
- Jie Luo
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA 19104
| | - Jon Lindstrom
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA 19104
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14
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Yu H, Stowell SR, Bernardo L, Hendrickson JE, Zimring JC, Amash A, Uchikawa M, Lazarus AH. Antibody-mediated immune suppression of erythrocyte alloimmunization can occur independently from red cell clearance or epitope masking in a murine model. THE JOURNAL OF IMMUNOLOGY 2014; 193:2902-10. [PMID: 25122924 DOI: 10.4049/jimmunol.1302287] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Anti-D can prevent immunization to the RhD Ag on RBCs, a phenomenon commonly termed Ab-mediated immune suppression (AMIS). The most accepted theory to explain this effect has been the rapid clearance of RBCs. In mouse models using SRBC, these xenogeneic cells are always rapidly cleared even without Ab, and involvement of epitope masking of the SRBC Ags by the AMIS-inducing Ab (anti-SRBC) has been suggested. To address these hypotheses, we immunized mice with murine transgenic RBCs expressing the HOD Ag (hen egg lysozyme [HEL], in sequence with ovalbumin, and the human Duffy transmembrane protein) in the presence of polyclonal Abs or mAbs to the HOD molecule. The isotype, specificity, and ability to induce AMIS of these Abs were compared with accelerated clearance as well as steric hindrance of the HOD Ag. Mice made IgM and IgG reactive with the HEL portion of the molecule only. All six of the mAbs could inhibit the response. The HEL-specific Abs (4B7, IgG1; GD7, IgG2b; 2F4, IgG1) did not accelerate clearance of the HOD-RBCs and displayed partial epitope masking. The Duffy-specific Abs (MIMA 29, IgG2a; CBC-512, IgG1; K6, IgG1) all caused rapid clearance of HOD RBCs without steric hindrance. To our knowledge, this is the first demonstration of AMIS to erythrocytes in an all-murine model and shows that AMIS can occur in the absence of RBC clearance or epitope masking. The AMIS effect was also independent of IgG isotype and epitope specificity of the AMIS-inducing Ab.
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Affiliation(s)
- Honghui Yu
- The Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada; Department of Anesthesiology, Tongji Hospital, Huazhong University of Science and Technology, 430030 Wuhan, China; Department of Laboratory Medicine, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - Sean R Stowell
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Lidice Bernardo
- The Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada; Department of Laboratory Medicine, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | | | - James C Zimring
- Puget Sound Blood Center Research Institute, Seattle, WA 98102
| | - Alaa Amash
- Department of Laboratory Medicine, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - Makoto Uchikawa
- Kanto-Koshinetsu Block Blood Center, Japanese Red Cross, Koto-ku, Tokyo, Japan 135-8639
| | - Alan H Lazarus
- The Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada; Department of Laboratory Medicine, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A1, Canada; and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A1, Canada
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15
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Abstract
Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder caused by low numbers of platelets generally due to the production of anti-platelet antibodies. One effective treatment for ITP patients who express the RhD antigen on their red blood cells has been the use of blood donor-derived pooled polyclonal anti-D. Although anti-D has served us well, it needs to be replaced with a recombinant product. While the mechanism of action of anti-D in ITP remains highly speculative, this has not thwarted attempts to replace anti-D with a monoclonal product. Although a single attempt at a monoclonal antibody was not successful in the 1990s for the treatment of ITP, more recent efforts in mouse models of ITP and ITP patients now show that monoclonal antibodies can be successful in ITP. These studies also finally help substantiate the concept that it is unlikely that contaminants in the original donor-derived preparations mediate the major ameliorative activity of anti-D in ITP.
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Affiliation(s)
- Alan H Lazarus
- University of Toronto, Department of Laboratory Medicine and the Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, The Canadian Blood Services, Departments of Medicine and Laboratory Medicine & Pathobiology , 30 Bond St, Toronto, Ontario, M5B 1W8 , Canada
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16
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Stowell SR, Girard-Pierce KR, Smith NH, Henry KL, Arthur CM, Zimring JC, Hendrickson JE. Transfusion of murine red blood cells expressing the human KEL glycoprotein induces clinically significant alloantibodies. Transfusion 2013; 54:179-89. [PMID: 23621760 DOI: 10.1111/trf.12217] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/13/2013] [Accepted: 03/14/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND Red blood cell (RBC) alloantibodies to nonself antigens may develop after transfusion or pregnancy, leading to morbidity and mortality in the form of hemolytic transfusion reactions or hemolytic disease of the newborn. A better understanding of the mechanisms of RBC alloantibody induction, or strategies to mitigate the consequences of such antibodies, may ultimately improve transfusion safety. However, such studies are inherently difficult in humans. STUDY DESIGN AND METHODS We recently generated transgenic mice with RBC-specific expression of the human KEL glycoprotein, specifically the KEL2 or KEL1 antigens. Herein, we investigate recipient alloimmune responses to transfused RBCs in this system. RESULTS Transfusion of RBCs from KEL2 donors into wild-type recipients (lacking the human KEL protein but expressing the murine KEL ortholog) resulted in dose-dependent anti-KEL glycoprotein immunoglobulin (Ig)M and IgG antibody responses, enhanced by recipient inflammation with poly(I:C). Boostable responses were evident upon repeat transfusion, with morbid-appearing alloimmunized recipients experiencing rapid clearance of transfused KEL2 but not control RBCs. Although KEL1 RBCs were also immunogenic after transfusion into wild-type recipients, transfusion of KEL1 RBCs into KEL2 recipients or vice versa failed to lead to detectable anti-KEL1 or anti-KEL2 responses. CONCLUSIONS This murine model, with reproducible and clinically significant KEL glycoprotein alloantibody responses, provides a platform for future mechanistic studies of RBC alloantibody induction and consequences. Long-term translational goals of these studies include improving transfusion safety for at-risk patients.
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Affiliation(s)
- Sean R Stowell
- Department of Pathology, Emory University, Atlanta, Georgia; Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, Atlanta, Georgia; Puget Sound Blood Center Research Institute, Seattle, Washington
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McGann PT, Despotovic JM, Howard TA, Ware RE. A novel laboratory technique demonstrating the influences of RHD zygosity and the RhCcEe phenotype on erythrocyte D antigen expression. Am J Hematol 2012; 87:266-71. [PMID: 22121029 DOI: 10.1002/ajh.22254] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/21/2011] [Accepted: 11/08/2011] [Indexed: 11/11/2022]
Abstract
D antigen is the most immunogenic and clinically relevant antigen within the complex Rh blood group system. Variability of D antigen expression was first described decades ago but has rarely been investigated quantitatively, particularly in the context of RHD zygosity along with RhCcEe serological phenotype. With IRB approval, 107 deidentified blood samples were analyzed. Rh phenotypes were determined serologically by saline technique using monoclonal antibodies against D, C, c, E, and e antigens. RHD zygosity was determined using both PCR-restriction fragment length polymorphisms and quantitative real-time PCR techniques. A novel and robust method was developed for quantitation of erythrocyte D antigen sites using calibrated microspheres and flow cytometry, allowing correlation of D antigen density with RHD zygosity and expression of Rh CcEe antigens. Subjects homozygous for RHD expressed nearly twice the number of D antigen sites compared with RHD hemizygotes (33,560 ± 8,222 for DD versus 17,720 ± 4,471 for Dd, P < 0.0001). Expression of c or E antigens was associated with significantly increased erythrocyte D antigen expression, whereas presence of C or e antigens reduced expression. These data and this novel quantitation method will be important for future studies investigating the clinical relevance of D antigen variability.
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Affiliation(s)
- Patrick T McGann
- Baylor International Hematology Center of Excellence and the Texas Children's Center for Global Health, Houston, Texas, USA.
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