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Gil Gonzalez L, Won KD, Tawhidi Z, Cummins E, Cruz-Leal Y, Tundidor Cabado Y, Sachs UJ, Norris PAA, Shan Y, Bhakta V, Li J, Samudio I, Silva-Moreno B, Cerna-Portillo L, Pavon Oro A, Bergqvist P, Chan P, Moorehead A, Sholzberg M, Sheffield WP, Lazarus AH. Human Fc gamma receptor IIIA blockade inhibits platelet destruction in a humanized murine model of ITP. Blood Adv 2024; 8:1869-1879. [PMID: 38330193 PMCID: PMC11007428 DOI: 10.1182/bloodadvances.2023012155] [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: 11/13/2023] [Revised: 01/08/2024] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
ABSTRACT Fc gamma receptor (FcγR) IIIA is an important receptor for immunoglobulin G (IgG) and is involved in immune defense mechanisms as well as tissue destruction in some autoimmune diseases including immune thrombocytopenia (ITP). FcγRIIIA on macrophages can trigger phagocytosis of IgG-sensitized platelets, and prior pilot studies observed blockade of FcγRIIIA increased platelet counts in patients with ITP. Unfortunately, although blockade of FcγRIIIA in patients with ITP increased platelet counts, its engagement by the blocking antibody drove serious adverse inflammatory reactions. These adverse events were postulated to originate from the antibody's Fc and/or bivalent nature. The blockade of human FcγRIIIA in vivo with a monovalent construct lacking an active Fc region has not yet been achieved. To effectively block FcγRIIIA in vivo, we developed a high affinity monovalent single-chain variable fragment (scFv) that can bind and block human FcγRIIIA. This scFv (17C02) was expressed in 3 formats: a monovalent fusion protein with albumin, a 1-armed human IgG1 antibody, and a standard bivalent mouse (IgG2a) antibody. Both monovalent formats were effective in preventing phagocytosis of ITP serum-sensitized human platelets. In vivo studies using FcγR-humanized mice demonstrated that both monovalent therapeutics were also able to increase platelet counts. The monovalent albumin fusion protein did not have adverse event activity as assessed by changes in body temperature, whereas the 1-armed antibody induced some changes in body temperature even though the Fc region function was impaired by the Leu234Ala and Leu235Ala mutations. These data demonstrate that monovalent blockade of human FcγRIIIA in vivo can potentially be a therapeutic strategy for patients with ITP.
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Affiliation(s)
- Lazaro Gil Gonzalez
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Kevin D. Won
- 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
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zoya Tawhidi
- 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
| | | | - Yoelys Cruz-Leal
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
| | - Yaima Tundidor Cabado
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Ulrich J. Sachs
- Institute for Clinical Immunology, Transfusion Medicine, and Haemostasis, Justus Liebig University, Giessen, Germany
- Department of Thrombosis and Haemostasis, Giessen University Hospital, Giessen, Germany
| | - Peter A. A. Norris
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Yuexin Shan
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Varsha Bhakta
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
| | - Janessa Li
- adMare BioInnovations, Vancouver, BC, Canada
| | | | | | | | - Alequis Pavon Oro
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | | | | | - Amy Moorehead
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Michelle Sholzberg
- 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
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - William P. Sheffield
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
| | - Alan H. Lazarus
- 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
- Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Innovation and Portfolio Management, Canadian Blood Services, Ottawa, ON, Canada
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Lv Y, Shi H, Liu H, Zhou L. Current therapeutic strategies and perspectives in refractory ITP: What have we learned recently? Front Immunol 2022; 13:953716. [PMID: 36003388 PMCID: PMC9393521 DOI: 10.3389/fimmu.2022.953716] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Immune thrombocytopenia (ITP) is an acquired autoimmune bleeding disorder featured by increased platelet destruction and deficient megakaryocyte maturation. First-line treatments include corticosteroids, intravenous immunoglobulin and intravenous anti-D immunoglobulin. Second-line treatments consist of rituximab, thrombopoietin receptor agonists and splenectomy. Although most patients benefit from these treatments, an individualized treatment approach is warranted due to the large heterogeneity among ITP patients. In addition, ITP patients may relapse and there remains a subset of patients who become refractory to treatments. The management of these refractory patients is still a challenge. This review aims to summarize emerging therapeutic approaches for refractory ITP in several categories according to their different targets, including macrophages, platelets/megakaryocytes, T cells, B cells, and endothelial cells. Moreover, current management strategies and combination regimens of refractory ITP are also discussed.
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Affiliation(s)
- Yue Lv
- Department of Hematology, Affiliated Hospital and Medical School of Nantong University, Nantong, China
| | - Huiping Shi
- Soochow University Medical College, Suzhou, China
| | - Hong Liu
- Department of Hematology, Affiliated Hospital and Medical School of Nantong University, Nantong, China
- *Correspondence: Lu Zhou, ; Hong Liu,
| | - Lu Zhou
- Department of Hematology, Affiliated Hospital and Medical School of Nantong University, Nantong, China
- *Correspondence: Lu Zhou, ; Hong Liu,
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New insights into IVIg mechanisms and alternatives in autoimmune and inflammatory diseases. Curr Opin Hematol 2021; 27:392-398. [PMID: 32868670 DOI: 10.1097/moh.0000000000000609] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Intravenous immunoglobulin (IVIg) is an effective treatment for an increasing number of autoimmune and inflammatory conditions. However, IVIg continues to be limited by problems of potential shortages and cost. A number of mechanisms have been described for IVIg, which have been captured in newly emergent IVIg mimetic and IVIg alternative therapies. This review discusses the recent developments in IVIg mimetics and alternatives. RECENT FINDINGS Newly emergent IVIg mimetics and alternatives capture major proposed mechanisms of IVIg, including FcγR blockade, FcRn inhibition, complement inhibition, immune complex mimetics and sialylated IgG. Many of these emergent therapies have promising preclinical and clinical trial results. SUMMARY Significant research has been undertaken into the mechanism of IVIg in the treatment of autoimmune and inflammatory disease. Understanding the major IVIg mechanisms has allowed for rational development of IVIg mimetics and alternatives for several IVIg-treatable diseases.
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Anti-inflammatory activity of CD44 antibodies in murine immune thrombocytopenia is mediated by Fcγ receptor inhibition. Blood 2021; 137:2114-2124. [PMID: 33662988 DOI: 10.1182/blood.2020009497] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 02/11/2021] [Indexed: 02/03/2023] Open
Abstract
Monoclonal immunoglobulin G (IgG) antibodies to CD44 (anti-CD44) are anti-inflammatory in numerous murine autoimmune models, but the mechanisms are poorly understood. Anti-CD44 anti-inflammatory activity shows complete therapeutic concordance with IV immunoglobulin (IVIg) in treating autoimmune disease models, making anti-CD44 a potential IVIg alternative. In murine immune thrombocytopenia (ITP), there is no mechanistic explanation for anti-CD44 activity, although anti-CD44 ameliorates disease similarly to IVIg. Here, we demonstrate a novel anti-inflammatory mechanism of anti-CD44 that explains disease amelioration by anti-CD44 in murine ITP. Macrophages treated with anti-CD44 in vitro had dramatically suppressed phagocytosis through FcγRs in 2 separate systems of IgG-opsonized platelets and erythrocytes. Phagocytosis inhibition by anti-CD44 was mediated by blockade of the FcγR IgG binding site without changing surface FcγR expression. Anti-CD44 of different subclasses revealed that FcγR blockade was specific to receptors that could be engaged by the respective anti-CD44 subclass, and Fc-deactivated anti-CD44 variants lost all FcγR-inhibiting activity. In vivo, anti-CD44 functioned analogously in the murine passive ITP model and protected mice from ITP when thrombocytopenia was induced through an FcγR that could be engaged by the CD44 antibody's subclass. Consistent with FcγR blockade, Fc-deactivated variants of anti-CD44 were completely unable to ameliorate ITP. Together, anti-CD44 inhibits macrophage FcγR function and ameliorates ITP consistent with an FcγR blockade mechanism. Anti-CD44 is a potential IVIg alternative and may be of particular benefit in ITP because of the significant role that FcγRs play in human ITP pathophysiology.
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Antihuman CD44 antibody BJ18 inhibits platelet phagocytosis by correcting aberrant FcɣR expression and M1 polarization in immune thrombocytopenia. Int Immunopharmacol 2021; 95:107502. [PMID: 33690000 DOI: 10.1016/j.intimp.2021.107502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disease with a low platelet count. CD44 is a pivotal component involved in phagocytosis and inflammation, and monoclonal antibodies (mAbs) against CD44 have been shown to be beneficial in several autoimmune diseases. In the present study, we investigated the correlation between CD44 levels and disease severity in patients with ITP and explored the immunomodulatory mechanisms of the antihuman CD44 mAb BJ18 on platelet phagocytosis mediated by monocytes/macrophages. METHODS Plasma was collected from 45 participants to measure the circulating concentration of CD44 using ELISA. Peripheral blood mononuclear cells from patients and controls were isolated and induced to differentiate into monocytes/macrophages utilizing cytokines and drugs. CD44 expression on circulating cells and the effects of BJ18 on platelet phagocytosis, Fcɣ receptor (FcɣR) expression and M1/M2 polarization of macrophages were evaluated using flow cytometry and qPCR. RESULTS CD44 levels of both the soluble form found in plasma and the form expressed on the surface of circulating monocytes/macrophages were significantly elevated in ITP patients. Linear correlations were verified between the CD44 levels and major clinical characteristics. In an in vitro study, BJ18 successfully inhibited platelet phagocytosis by monocytes/macrophages obtained from ITP patients. Further studies indicated that BJ18 corrected abnormal FcγR expression on monocytes/macrophages. Moreover, the polarization of proinflammatory M1 macrophages could also be regulated by BJ18. CONCLUSIONS Our data indicated that the CD44 level has potential predictive value for disease severity and that the antihuman CD44 mAb BJ18 may be a promising therapy for ITP patients.
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Crow AR, Kapur R, Koernig S, Campbell IK, Jen CC, Mott PJ, Marjoram D, Khan R, Kim M, Brasseit J, Cruz-Leal Y, Amash A, Kahlon S, Yougbare I, Ni H, Zuercher AW, Käsermann F, Semple JW, Lazarus AH. Treating murine inflammatory diseases with an anti-erythrocyte antibody. Sci Transl Med 2020; 11:11/506/eaau8217. [PMID: 31434758 DOI: 10.1126/scitranslmed.aau8217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/08/2019] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
Abstract
Treatment of autoimmune and inflammatory diseases typically involves immune suppression. In an opposite strategy, we show that administration of the highly inflammatory erythrocyte-specific antibody Ter119 into mice remodels the monocyte cellular landscape, leading to resolution of inflammatory disease. Ter119 with intact Fc function was unexpectedly therapeutic in the K/BxN serum transfer model of arthritis. Similarly, it rapidly reversed clinical disease progression in collagen antibody-induced arthritis (CAIA) and collagen-induced arthritis and completely corrected CAIA-induced increase in monocyte Fcγ receptor II/III expression. Ter119 dose-dependently induced plasma chemokines CCL2, CCL5, CXCL9, CXCL10, and CCL11 with corresponding alterations in monocyte percentages in the blood and liver within 24 hours. Ter119 attenuated chemokine production from the synovial fluid and prevented the accumulation of inflammatory cells and complement components in the synovium. Ter119 could also accelerate the resolution of hypothermia and pulmonary edema in an acute lung injury model. We conclude that this inflammatory anti-erythrocyte antibody simultaneously triggers a highly efficient anti-inflammatory effect with broad therapeutic potential.
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Affiliation(s)
- Andrew R Crow
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada.,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Rick Kapur
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada.,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada.,Department of Hematology and Transfusion Medicine, Lund University, Lund 221 84, Sweden.,Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, Netherlands
| | - Sandra Koernig
- CSL Limited, Bio21 Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ian K Campbell
- CSL Limited, Bio21 Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Chao-Ching Jen
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Patrick J Mott
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Danielle Marjoram
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Ramsha Khan
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Michael Kim
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Jennifer Brasseit
- CSL Behring, Research, CSL Biologics Research Center, Bern, Switzerland
| | - Yoelys Cruz-Leal
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada.,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Alaa Amash
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Simrat Kahlon
- Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Issaka Yougbare
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada.,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada
| | - Heyu Ni
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada.,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada.,Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Adrian W Zuercher
- CSL Behring, Research, CSL Biologics Research Center, Bern, Switzerland
| | - Fabian Käsermann
- CSL Behring, Research, CSL Biologics Research Center, Bern, Switzerland
| | - John W Semple
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada.,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada.,Department of Hematology and Transfusion Medicine, Lund University, Lund 221 84, Sweden.,Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Pharmacology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Alan H Lazarus
- Canadian Blood Services Centre for Innovation, Ottawa, Ontario K1G 4J5, Canada. .,Department of Laboratory Medicine and Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Toronto Platelet Immunobiology Group, Toronto, Ontario, M5B 1T8 Canada.,Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Zhang P, Zhang G, Liu X, Liu H, Yang P, Ma L. Mesenchymal stem cells improve platelet counts in mice with immune thrombocytopenia. J Cell Biochem 2019; 120:11274-11283. [PMID: 30775797 DOI: 10.1002/jcb.28405] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/27/2018] [Accepted: 12/06/2018] [Indexed: 01/24/2023]
Abstract
Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder. The breakdown of immune tolerance (regulatory T [Treg] cells and suppressor cytokines) plays an important role in ITP pathophysiology, especially in refractory ITP. Bone marrow-derived mesenchymal stem cells (BM-MSCs) show immunomodulatory properties and have been extensively utilized for autoimmune diseases. However, it has not been fully elucidated how BM-MSCs affect ITP. In this study, we explore the therapeutic mechanism of BM-MSCs on ITP in mice. Dose-escalation passive ITP mice were inducted by injection of MWReg30. BALB/c mice were randomly divided into two groups: ITP with BM-MSC transplantation and ITP controls. The serum levels of cytokines (interleukin 10 [IL-10] and transforming growth factor-β1 [TGF-β1]) were examined by enzyme-linked immunosorbent assays. The frequency of Treg cells in both peripheral blood and spleen mononuclear cells was analyzed by flow cytometry, and the forkhead box P3 (Foxp3) messenger RNA (mRNA) level was measured by real-time polymerase chain reaction. After BM-MSC treatment, the platelet (PLT) counts were significantly elevated. Meanwhile, cytokines (TGF-β1 and IL-10), the ratios of Treg cells, and the Foxp3 mRNA expression level were significantly higher in the BM-MSC group. Our results show that BM-MSCs can improve PLT counts mainly by secreting suppressive cytokines and upregulating Tregs, which may provide new therapeutic potential for human ITP.
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Affiliation(s)
- Ping Zhang
- Department of Hematology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China.,Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Guoyang Zhang
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xiaoyan Liu
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hongyun Liu
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Pengfeng Yang
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Liping Ma
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
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Thrombopoietin receptor agonists shift the balance of Fcγ receptors toward inhibitory receptor IIb on monocytes in ITP. Blood 2016; 128:852-61. [PMID: 27281793 DOI: 10.1182/blood-2016-01-690727] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 06/01/2016] [Indexed: 12/25/2022] Open
Abstract
Elevated expression of the activating Fcγ receptor (FcγR) I and FcγRIIa together with decreased expression of the inhibitory FcγRIIb are involved in the pathogenesis of primary immune thrombocytopenia (ITP). Thrombopoietin receptor agonists (TPO-RAs) have been used clinically for the management of ITP; however, little is known about the effect of TPO-RAs on FcγR modulation in ITP. In this prospective study, we measured the alteration in monocyte FcγR expression from 21 corticosteroid-resistant/relapsed patients with chronic ITP receiving eltrombopag therapy. Results showed that the mRNA and protein levels of FcγRIIb were significantly elevated after 6-week eltrombopag treatment. Concurrently, FcγRI and IIa levels decreased remarkably, whereas FcγRIII expression did not change. In vitro phagocytosis assays indicated that a shift in the balance of FcγR toward inhibitory FcγRIIb on monocytes was accompanied with a considerable decrease in monocyte/macrophage phagocytic capacity. The response to eltrombopag therapy in patients with ITP was associated with FcγR phenotype and functional changes of monocytes/macrophages. Moreover, the plasma transforming growth factor-β1 (TGF-β1) concentrations increased significantly in eltrombopag responders. Modulation of monocyte FcγR balance by TPO-RAs was also found in a murine model of ITP established by transferring splenocytes from immunized CD61 knockout mice into CD61(+) severe combined immunodeficient mice. Romiplostim administration in ITP mice significantly upregulated inhibitory FcγRII expression and downregulated activating FcγRI expression. These findings showed that recovery of platelet counts after TPO-RA treatment in ITP is associated with the restoration of FcγR balance toward the inhibitory FcγRIIb on monocytes, and suggested that thrombopoietic agents have a profound effect on immune modulation in ITP. This study is registered at ClinicalTrials.gov as #NCT01864512.
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9
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Crow AR, Lazarus AH. Mechanistic properties of intravenous immunoglobulin in murine immune thrombocytopenia: support for FcγRIIB falls by the wayside. Semin Hematol 2016; 53 Suppl 1:S20-2. [DOI: 10.1053/j.seminhematol.2016.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Bernardo L, Yu H, Amash A, Zimring JC, Lazarus AH. IgG-Mediated Immune Suppression to Erythrocytes by Polyclonal Antibodies Can Occur in the Absence of Activating or Inhibitory Fcγ Receptors in a Full Mouse Model. THE JOURNAL OF IMMUNOLOGY 2015; 195:2224-30. [PMID: 26188060 DOI: 10.4049/jimmunol.1500790] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 06/22/2015] [Indexed: 01/01/2023]
Abstract
Polyclonal anti-D has been used to prevent RhD-negative mothers from becoming immunized against RhD positive fetal erythrocytes, and this mechanism has been referred as Ab or IgG-mediated immune suppression (AMIS). Although anti-D has been highly successful, the inhibitory mechanisms remain poorly understood. Two major theories behind AMIS involve the binding of IgG to activating or inhibitory FcγR, which can induce either erythrocyte clearance or immune inhibition, respectively. In this work, we explored the absolute role of activating and inhibitory FcγR in the AMIS mechanism using the HOD mouse model of RBC immunization. HOD mice contain a RBC-specific recombinant protein composed of hen egg lysozyme (HEL), OVA and human transmembrane Duffy Ag, and erythrocytes from HOD mice can stimulate an immune response to HEL. To assess the contribution of activating and inhibitory FcγR to AMIS, C57BL/6 versus FcRγ-chain(-/-) or FcγRIIB(-/-) mice were used as recipients of HOD-RBC alone or together with anti-HEL Abs (i.e., AMIS) and the resulting immune response to HEL evaluated. We show that anti-HEL polyclonal Abs induce the same degree of AMIS effect in mice lacking these IgG binding receptors as compared with wild-type mice. In agreement with this, F(ab')2 fragments of the AMIS Ab also significantly reduced the Ab response to the HOD cells. In conclusion, successful inhibition of in vivo Ab responses to HOD-RBC by polyclonal IgG can occur independently of activating or inhibitory FcγR involvement. These results may have implications for the understanding of RhD prophylaxis.
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Affiliation(s)
- Lidice Bernardo
- Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada; Department of Laboratory Medicine, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - Honghui Yu
- Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada; Department of Laboratory Medicine, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Department of Anesthesiology, Tongji Hospital, Huazhong University of Science and Technology, 430030 Wuhan, China
| | - Alaa Amash
- Department of Laboratory Medicine, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
| | - James C Zimring
- Bloodworks Northwest Research Institute, South Lake Union, Seattle, WA 98102
| | - Alan H Lazarus
- Canadian Blood Services, Ottawa, Ontario K1G 4J5, Canada; Department of Laboratory Medicine, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada; 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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