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Liu H, Wang W, Wang C, Li L, Wu J, Chen Y, Liu Z, Wang H, Li L, Fu R. Single-cell sequencing reveals alterations in the differentiation of bone marrow haematopoietic cells in patients with paroxysmal nocturnal haemoglobinuria. Clin Transl Med 2024; 14:e1671. [PMID: 38924689 PMCID: PMC11199056 DOI: 10.1002/ctm2.1671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/04/2024] [Accepted: 04/08/2024] [Indexed: 06/28/2024] Open
Affiliation(s)
- Hui Liu
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Wei Wang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and TechnologyShanghaiTech UniversityShanghaiPeople's Republic of China
| | - Chaomeng Wang
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Liyan Li
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Junshu Wu
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Yingying Chen
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Zhaoyun Liu
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Honglei Wang
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Lijuan Li
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
| | - Rong Fu
- Department of HematologyTianjin Medical University General HospitalTianjinPeople's Republic of China
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Bravo-Perez C, Guarnera L, Williams ND, Visconte V. Paroxysmal Nocturnal Hemoglobinuria: Biology and Treatment. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1612. [PMID: 37763731 PMCID: PMC10535188 DOI: 10.3390/medicina59091612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/22/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a nonmalignant clonal hematopoietic disorder characterized by the lack of glycosylphosphatidylinositol-anchored proteins (GPI-APs) as a consequence of somatic mutations in the phosphatidylinositol glycan anchor biosynthesis class A (PIGA) gene. Clinical manifestations of PNH are intravascular hemolysis, thrombophilia, and bone marrow failure. Treatment of PNH mainly relies on the use of complement-targeted therapy (C5 inhibitors), with the newest agents being explored against other factors involved in the complement cascade to alleviate unresolved intravascular hemolysis and extravascular hemolysis. This review summarizes the biology and current treatment strategies for PNH with the aim of reaching a general audience with an interest in hematologic disorders.
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Affiliation(s)
- Carlos Bravo-Perez
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44114, USA; (C.B.-P.); (L.G.); (N.D.W.)
- Department of Hematology and Medical Oncology, Hospital Universitario Morales Meseguer, IMIB-Pascual Parrilla, CIBERER—Instituto de Salud Carlos III, University of Murcia, 30005 Murcia, Spain
| | - Luca Guarnera
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44114, USA; (C.B.-P.); (L.G.); (N.D.W.)
- Hematology, Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Nakisha D. Williams
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44114, USA; (C.B.-P.); (L.G.); (N.D.W.)
| | - Valeria Visconte
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44114, USA; (C.B.-P.); (L.G.); (N.D.W.)
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Colden MA, Kumar S, Munkhbileg B, Babushok DV. Insights Into the Emergence of Paroxysmal Nocturnal Hemoglobinuria. Front Immunol 2022; 12:830172. [PMID: 35154088 PMCID: PMC8831232 DOI: 10.3389/fimmu.2021.830172] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/30/2021] [Indexed: 11/13/2022] Open
Abstract
Paroxysmal Nocturnal Hemoglobinuria (PNH) is a disease as simple as it is complex. PNH patients develop somatic loss-of-function mutations in phosphatidylinositol N-acetylglucosaminyltransferase subunit A gene (PIGA), required for the biosynthesis of glycosylphosphatidylinositol (GPI) anchors. Ubiquitous in eukaryotes, GPI anchors are a group of conserved glycolipid molecules responsible for attaching nearly 150 distinct proteins to the surface of cell membranes. The loss of two GPI-anchored surface proteins, CD55 and CD59, from red blood cells causes unregulated complement activation and hemolysis in classical PNH disease. In PNH patients, PIGA-mutant, GPI (-) hematopoietic cells clonally expand to make up a large portion of patients’ blood production, yet mechanisms leading to clonal expansion of GPI (-) cells remain enigmatic. Historical models of PNH in mice and the more recent PNH model in rhesus macaques showed that GPI (-) cells reconstitute near-normal hematopoiesis but have no intrinsic growth advantage and do not clonally expand over time. Landmark studies identified several potential mechanisms which can promote PNH clonal expansion. However, to what extent these contribute to PNH cell selection in patients continues to be a matter of active debate. Recent advancements in disease models and immunologic technologies, together with the growing understanding of autoimmune marrow failure, offer new opportunities to evaluate the mechanisms of clonal expansion in PNH. Here, we critically review published data on PNH cell biology and clonal expansion and highlight limitations and opportunities to further our understanding of the emergence of PNH clones.
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Affiliation(s)
- Melissa A. Colden
- Division of Hematology-Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Comprehensive Bone Marrow Failure Center, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Sushant Kumar
- Division of Hematology-Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Comprehensive Bone Marrow Failure Center, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Bolormaa Munkhbileg
- Division of Hematology-Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Comprehensive Bone Marrow Failure Center, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Daria V. Babushok
- Division of Hematology-Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Comprehensive Bone Marrow Failure Center, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- *Correspondence: Daria V. Babushok,
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Szlendak U, Krzymieniewska B, Mendek-Czajkowska E, Rogatko-Koroś M, Witkowska A, Włodarska J, Drozd-Sokołowska J, Spychalska J, Budziszewska B, Patkowska E, Woźniak J, Krzywdzińska A, Jurek S, Juszczyński P, Jaworska M, Rosłon M, Gruber-Bzura B, Wasilewski R, Baran B, Windyga J, Nowak J. Persistent imbalance, anti-apoptotic, and anti-inflammatory signature of circulating C-C chemokines and cytokines in patients with paroxysmal nocturnal hemoglobinuria. Cytokine 2021; 150:155780. [PMID: 34896730 DOI: 10.1016/j.cyto.2021.155780] [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: 09/29/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal non-malignant disease in which hematopoietic cell apoptosis may play an important pathophysiological role. Previous studies of the content of phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) indicated the possibility of remote transmission of anti-apoptotic signals between pathological and normal hematopoietic progenitors. METHODS The study determined the plasma levels of beta chemokines and cytokines in N = 19 patients with PNH and 31 healthy controls. The research material was peripheral blood plasma (EDTA) stored at -80 °C until the test. Beta chemokine and cytokine concentrations were tested in duplicate with Bio-Plex Pro Human Cytokine Assay (Bio-Rad, Hercules, CA, USA) using a Luminex 200 flow cytometer and xPONENT software (Luminex Corporation, Austin, TX, USA). In peripheral blood CD34+ cells we tested the proportions of PI(3,4,5)P3+ and Annexin binding apoptotic phenotype using FC and phosflow. RESULTS Compared to the control group, the PNH group showed a significant increase in the plasma concentration of some beta chemokines and cytokines, including MIP-1alpha/CCL3, eotaxin/CCL11, MCP1/CCL2, IL4 and G-CSF. In the group of PNH patients, a significant decrease in the concentration of some cytokines was also observed: RANTES/CCL5, MIP-1beta/CCL4, PDGF-BB and IL9. At the same time, the plasma concentrations of the chemokine IP-10/CXCL10 and the cytokines IFN-gamma, TNF, IL6 and IL10 showed no significant deviations from the values for the control group. Anti-apoptotic phenotype and phosphatidylinositol (3,4,5)-trisphosphate content in PNH clone of CD34+ cells were associated with the level of CCL3 and negatively associated with CCL5, CCL4, PDGF-BB and IL9. CONCLUSIONS This data suggest the existence of apoptotic and PI(3,4,5)P3 imbalance in PNH CD34+ cells driven by anti-apoptotic cytokine biosignature in PNH. Plasma cytokines and intracellular enzymes that regulate the phosphoinositide pathways may become a therapeutic target in PNH.
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Affiliation(s)
- Urszula Szlendak
- Department of Immunogenetics, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Beata Krzymieniewska
- Laboratory of Immunophenotyping, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Ewa Mendek-Czajkowska
- Specialist Outpatient Clinic, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Marta Rogatko-Koroś
- Department of Immunogenetics, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Agnieszka Witkowska
- Department of Immunogenetics, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Joanna Włodarska
- Day Treatment Department, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Joanna Drozd-Sokołowska
- Department of Hematology, Transplantology and Internal Medicine, University Clinical Center, Medical University of Warsaw, Warsaw, Poland
| | - Justyna Spychalska
- Department of Hematological and Transfusion Immunology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Bożena Budziszewska
- Department of Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Elżbieta Patkowska
- Department of Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Jolanta Woźniak
- Laboratory of Immunophenotyping, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Agnieszka Krzywdzińska
- Laboratory of Immunophenotyping, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Sławomir Jurek
- Department of Disorders of Hemostasis and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Przemysław Juszczyński
- Department of Experimental Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Małgorzata Jaworska
- Department of Biochemistry and Biopharmaceuticals, National Medicines Institute, Warsaw, Poland
| | - Magdalena Rosłon
- Department of Biochemistry and Biopharmaceuticals, National Medicines Institute, Warsaw, Poland
| | - Beata Gruber-Bzura
- Department of Biochemistry and Biopharmaceuticals, National Medicines Institute, Warsaw, Poland
| | - Robert Wasilewski
- Department of Disorders of Hemostasis and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Beata Baran
- Department of Hemostasis and Metabolic Diseases, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Jerzy Windyga
- Department of Disorders of Hemostasis and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Jacek Nowak
- Department of Immunogenetics, Institute of Hematology and Transfusion Medicine, Warsaw, Poland.
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Immunologic effects on the haematopoietic stem cell in marrow failure. Best Pract Res Clin Haematol 2021; 34:101276. [PMID: 34404528 DOI: 10.1016/j.beha.2021.101276] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 02/07/2023]
Abstract
Acquired bone marrow failure (BMF) syndromes comprise a diverse group of diseases with variable clinical manifestations but overlapping features of immune activation, resulting in haematopoietic stem and progenitor cells (HSPC) damage and destruction. This review focuses on clinical presentation, pathophysiology, and treatment of four BMF: acquired aplastic anaemia, large granular lymphocytic leukaemia, paroxysmal nocturnal haemoglobinuria, and hypoplastic myelodysplastic syndrome. Autoantigens are speculated to be the inciting event that result in immune activation in all of these diseases, but specific pathogenic antigens have not been identified. Oligoclonal cytotoxic T cell expansion and an active role of proinflammatory cytokines, primarily interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α), are two main contributors to HSPC growth inhibition and apoptosis in BMF. Emerging evidence also suggests involvement of the innate immune system.
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Kalam S, Beale R, Hughes D, Kulasekararaj A, Srirangalingam U. Coombs-positive Paroxysmal Nocturnal Haemoglobinuria. Oxf Med Case Reports 2020; 2020:omz125. [PMID: 32257252 PMCID: PMC7104188 DOI: 10.1093/omcr/omz125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 04/22/2018] [Accepted: 10/27/2019] [Indexed: 11/24/2022] Open
Abstract
Autoimmune haemolytic anaemia (AIHA) and paroxysmal nocturnal haemoglobinuria (PNH) are two distinct causes of haemolytic anaemia. They have different mechanisms that underpin their pathogenesis and, therefore, require different treatment strategies. The direct antiglobulin test (DAT) or Coombs test is positive in cases of immune-mediated haemolytic anaemia and, thus, is positive in AIHA but negative in PNH. We report a case of a woman presenting with a haemolytic anaemia who was found to have concomitant evidence of AIHA and PNH. The case highlights the importance of carrying out a comprehensive haemolysis work-up in patients who present with haemolytic anaemia.
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Affiliation(s)
- Sabrina Kalam
- Department of Neurology, Charing Cross Hospital, London, W6 8RF, UK
| | - Rupert Beale
- Department of Nephrology, Royal Free Hospital, London NW3 2QG, UK
| | - Derralynn Hughes
- Department of Haematology, Royal Free Hospital, London NW3 2QG, UK
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Hosokawa K, Kajigaya S, Keyvanfar K, Qiao W, Xie Y, Biancotto A, Townsley DM, Feng X, Young NS. Whole transcriptome sequencing identifies increased CXCR2 expression in PNH granulocytes. Br J Haematol 2017; 177:136-141. [PMID: 28151558 DOI: 10.1111/bjh.14502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/09/2016] [Indexed: 01/26/2023]
Abstract
The aetiology of paroxysmal nocturnal haemoglobinuria (PNH) is a somatic mutation in the X-linked phosphatidylinositol glycan class A gene (PIGA), resulting in global deficiency of glycosyl phosphatidylinositol-anchored proteins (GPI-APs). This study applied RNA-sequencing to examine functional effects of the PIGA mutation in human granulocytes. CXCR2 expression was increased in GPI-AP- compared to GPI-AP+ granulocytes. Macrophage migration inhibitory factor, a CXCR2 agonist, was significantly higher in plasma of PNH patients. Nuclear factor-κB phosphorylation was upregulated in GPI-AP- compared with GPI-AP+ granulocytes. Our data suggest novel mechanisms in PNH, not obviously predicted by decreased production of the GPI moiety.
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Affiliation(s)
- Kohei Hosokawa
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
| | - Sachiko Kajigaya
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
| | - Keyvan Keyvanfar
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
| | | | | | - Angelique Biancotto
- Trans-NIH Center for Human Immunology, Autoimmunity, and Inflammation, NIH, Bethesda, MD, USA
| | - Danielle M Townsley
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
| | - Xingmin Feng
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
| | - Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, MD, USA
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Lee SCW, Abdel-Wahab O. The mutational landscape of paroxysmal nocturnal hemoglobinuria revealed: new insights into clonal dominance. J Clin Invest 2014; 124:4227-30. [PMID: 25244089 DOI: 10.1172/jci77984] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a disorder of hematopoietic stem cells that has largely been considered a monogenic disorder due to acquisition of mutations in the gene encoding PIGA, which is required for glycosylphosphatidylinositol (GPI) anchor biosynthesis. In this issue of the JCI, Shen et al. discovered that PNH is in fact a complex genetic disorder orchestrated by many genetic alterations in addition to PIGA mutations. Some of these mutations predate the acquisition of PIGA mutations, while others occur later. Surprisingly, this work indicates that PNH has a clonal evolution and architecture strikingly similar to that of other myeloid neoplasms, highlighting a potentially broader mechanism of disease pathogenesis in this disorder.
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Dublis S, Shah S, Nand S, Anderes E. Anemias excluding cobalamin and folate deficiencies. HANDBOOK OF CLINICAL NEUROLOGY 2014; 120:1005-1014. [PMID: 24365367 DOI: 10.1016/b978-0-7020-4087-0.00067-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Anemias are one of the commonest maladies affecting humans. They result from either a failure of production by the bone marrow (hypoproliferative), or from premature destruction or loss (hyperproliferative) of red cells. Hypoproliferative anemias typically result from deficiencies of essential nutrients, stem cell abnormalities or deficiency, and infiltrative processes of the bone marrow. In the hyperproliferative forms, the bone marrow function is normal and anemia results from bleeding or shortened erythrocyte lifespan due to hemoglobinopathies, red cell enzyme disorders, membrane defects, or external factors such as antibodies, trauma, or heat injury. The etiology of anemia is frequently obvious, but when obscure, a systematic diagnostic approach frequently yields the answer. It is important to realize that anemias are usually a consequence of another disease process, which must be identified. Without correction of the underlying disease process, the treatment is likely to fail.
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Affiliation(s)
- Stephanie Dublis
- Division of Hematology and Oncology, Department of Medicine, Loyola University Chicago, Stritch School of Medicine, Maywood, IL, USA
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Nowak J, Wozniak J, Mendek-Czajkowska E, Dlugokecka A, Mika-Witkowska R, Rogatko-Koros M, Graczyk-Pol E, Marosz-Rudnicka A, Dziopa J, Golec A, Kopec-Szlezak J, Warzocha K. Potential link between MHC-self-peptide presentation and hematopoiesis; the analysis of HLA-DR expression in CD34-positive cells and self-peptide presentation repertoires of MHC molecules associated with paroxysmal nocturnal hemoglobinuria. Cell Biochem Biophys 2013; 65:321-33. [PMID: 23076633 PMCID: PMC3601265 DOI: 10.1007/s12013-012-9435-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mechanisms of MHC allele associations with paroxysmal nocturnal hemoglobinuria (PNH) and its aplastic anemia subtype (AA/PNH) remain unclear. It might be dependent on MHC molecule functional properties, such as a scope and frequency of antigen sampling and presentation. For documented PNH-associated MHC alleles we analyzed current reference databases on MHC molecule-eluted peptide presentation repertoires and searched for a range of presented peptides. MHC class II expression was measured on CD34+ cells and appeared to be increased in PNH patients. Two class I alleles (HLA-A*24:02 and B*18:01) have been previously confirmed to associate with protection and increased risk of AA/PNH, respectively. Their product molecules presented immunodominant epitopes derived from proapoptotic (serine/threonine–protein phosphatase) and antiapoptotic (phospholipase D), respectively, intracellular enzymes dependent on phosphoinositide (PI) content. For total PNH and non-aplastic PNH (n/PNH) subtype-associated DRB1*15:01 and DRB1*04:01 class II molecules presentation of exceptionally broad arrays of their own peptide fragments has been found. We conclude that self antigen peptides presented with high frequency in the context of MHC molecules of increased expression may be involved in the immune recognition and the regulation of HSC in the periphery. The block in the normal plasma membrane PI production due to the PIG-A mutation can help explain the differences in the activation of intracellular regulatory pathways observed between PNH and normal HSC. This is evident in the variation in MHC association patterns and peptide presentation repertoires between these two groups of patients.
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Affiliation(s)
- Jacek Nowak
- Department of Immunogenetics Institute of Hematology and Transfusion Medicine, 14 Indira Gandhi Street, 02-776, Warsaw, Poland.
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Bone marrow histology in patients with a paroxysmal nocturnal hemoglobinuria clone correlated with clinical parameters. J Hematop 2013. [DOI: 10.1007/s12308-013-0179-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Kunyaboon R, Wanachiwanawin W, U-Pratya Y, Thedsawad A, Taka O. Mechanism of paroxysmal nocturnal hemoglobinuria clonal dominance: possible roles of different apoptosis and CD8+ lymphocytes in the selection of paroxysmal nocturnal hemoglobinuria clones. Hematol Oncol Stem Cell Ther 2013; 5:138-45. [PMID: 23095789 DOI: 10.5144/1658-3876.2012.138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Paroxysmal nocturnal hemoglobinuria (PNH), a clonal hematopoietic stem cell disorder, manifests when the PNH clone populates in the hematopoietic compartment. We explored the roles of different apoptosis of GPI+ and GPI- (glycosylphosphatidylinositol) cells and CD8+ lymphocytes in a selection of PNH clones. PATIENTS AND METHODS Granulocytes from PNH patients and normal controls were subjected to an apoptosis assay using annexin V. Hematopoietic cell in semisolid media were cultured with or without CD8+ lymphocytes. RESULTS In PNH, CD59+ granulocytes exhibited more apoptosis than their CD59- counterparts, after 0 or 4 hours in liquid growth culture system (mean [standard error of mean]: 2.1 (0.5) vs 1.2 (0.2), P=.01 at 0 hour and 3.4 [0.7] vs 1.8 [0.3], P=.03 at 4 hour, respectively). The presence of mononuclear cells (MNCs) rendered a greater difference in apoptosis. The percentages of apoptotic CD59+ granulocytes measured at 4 hours with or without MNC fraction were correlated with the sizes of PNH clones (r=0.633, P=.011; and r=0.648, P=.009; respectively). The autologous CD8+ lymphocytes inhibited CFU-GM and BFU-E colony formation in PNH patients when compared with normal controls (mean [SEM] of percentages of inhibition: 61.7 (10.4) vs 11.9 (2.0), P=.008 for CFU-GM and 26.1 (6.9) vs 4.9 (1.0), P=.037 for BFU-E). CONCLUSIONS Increased apoptosis of GPI+ blood cells is likely to be responsible in selection and expansion of PNH clones. MNCs or possibly CD8+ lymphocytes may play a role in this phenomenon.
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Affiliation(s)
- Rajita Kunyaboon
- Division of Hematology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Paroxysmal nocturnal hemoglobinuria and the complement system: recent insights and novel anticomplement strategies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 735:155-72. [PMID: 23402025 DOI: 10.1007/978-1-4614-4118-2_10] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a hematological disorder characterized by complement-mediated hemolytic anemia, thrombophilia, and bone marrow failure. PNH is due to a somatic, acquired mutation in the X-linked phosphatidylinositol glycan class A (PIG-A) gene, which impairs the membrane expression on affected blood cells of a number of proteins, including the complement regulators CD55 and CD59. The most evident clinical manifestations of PNH arise from dysregulated complement activation on blood cells; in fact, the hallmark of PNH is chronic, complement-mediated, intravascular hemolysis, which results in anemia, hemoglobinuria, fatigue, and other hemolysis-related disabling symptoms. In addition, the peculiar thromboembolic risk typical of PNH patients is thought as secondary to the complement-mediated hemolysis itself and/or to a complement-mediated activation of platelets. Thus, as a complement-mediated disease, PNH was an appropriate medical condition to develop and to investigate therapeutical complement inhibitors. Indeed, the first complement inhibitor eculizumab, a humanized anti-C5 monoclonal antibody, has been proven safe and effective for the treatment of PNH patients. Chronic treatment with eculizumab results in sustained control of intravascular hemolysis, leading to hemoglobin stabilization and transfusion independence in more than half of the patients. However, recent observations have demonstrated that residual anemia may persist in some patients regardless of sustained fluid-phase terminal complement inhibition. Indeed, persistent dysregulated activation of the early phases of the complement cascade on PNH erythrocytes may lead to progressive C3 deposition on affected cells, which become susceptible to subsequent extravascular hemolysis through the reticuloendothelial system. These findings have renewed the interest for the development of novel complement inhibitors which aim to modulate early phases of complement activation, more specifically at the level of C3 activation. As proof of principle of this concept, an anti-C3 monoclonal antibody has been proven effective in vitro to prevent hemolysis of PNH erythrocytes. More intriguingly, a human fusion protein consisting of the iC3b/ C3d-binding region of complement receptor 2 and of the inhibitory domain of the CAP regulator factor H has been recently shown effective in inhibiting, in vitro, both intravascular hemolysis of and surface C3-deposition on PNH erythrocytes, and is now under investigation in phase 1 clinical trials.
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Mannelli F, Bencini S, Peruzzi B, Cutini I, Sanna A, Benelli M, Magi A, Gianfaldoni G, Rotunno G, Carrai V, Gelli AMG, Valle V, Santini V, Notaro R, Luzzatto L, Bosi A. A systematic analysis of bone marrow cells by flow cytometry defines a specific phenotypic profile beyond GPI deficiency in paroxysmal nocturnal hemoglobinuria. CYTOMETRY PART B-CLINICAL CYTOMETRY 2012; 84:71-81. [PMID: 23281097 DOI: 10.1002/cyto.b.21064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 11/26/2012] [Accepted: 11/27/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Paroxysmal nocturnal hemoglobinuria (PNH) is a unique disorder caused by a PIG-A gene mutation in a stem cell clone. Its clinical picture can sometimes make challenging the distinction from other disorders, and especially from myelodysplastic syndromes (MDS), since both diseases correlate with cytopenias and morphological abnormalities of bone marrow (BM) cells. Recently, flow cytometry (FC) has been proposed to integrate the morphologic assessment of BM dysplasia, and thus to improve the diagnostics of MDS. METHODS In the present study, we have analyzed systematically FC data resulting from the study of BM cells from patients with PNH and MDS. RESULTS Our data demonstrated abnormalities in PNH beyond the deficiency of glycosylphosphatidylinositol-linked proteins and the application of a systematic approach allowed us to separate effectively MDS and PNH in a cluster analysis and to highlight disease-specific abnormalities. Indeed, the parallel evaluation of some key parameters, i.e. patterns of expression of CD45 and CD10, provided information with practical diagnostic usefulness in the distinction between PNH and MDS. Moreover, the hypo-expression of CD36 that we observed on monocytes might be related to the thrombotic tendency in PNH. CONCLUSIONS We investigated systematically the phenotypic profile of BM cells from patients with PNH; our data provide useful antigenic patterns to solve between PNH and MDS, sometimes morphologically overlapping. Moreover, some PNH-related phenotypic changes might be involved in the physiopathology of the disease and further studies addressing this issue are warranted.
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Affiliation(s)
- Francesco Mannelli
- Unità Funzionale di Ematologia, Università degli Studi, AOU Careggi, Florence, Italy.
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15
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Risitano AM, Rotoli B. Paroxysmal nocturnal hemoglobinuria: pathophysiology, natural history and treatment options in the era of biological agents. Biologics 2011; 2:205-22. [PMID: 19707355 PMCID: PMC2721357 DOI: 10.2147/btt.s1420] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal non-malignant hematological disease characterized by the expansion of hematopoietic stem cells (HSCs) and progeny mature cells, whose surfaces lack all the proteins linked through the glycosyl-phosphatidyl inositol anchor. This defect arises from an acquired somatic mutation in the X-linked phosphatidylinositol glycan class A gene, with subsequent clonal expansion of the mutated HSCs as a result of a concomitant, likely immune-mediated, selective pressure. The disease is characterized by complement-mediated chronic intravascular hemolysis, resulting in hemolytic anemia and hemosiderinuria; capricious exacerbations lead to recurrent gross hemoglobinuria. Additional cardinal manifestations of PNH are a variable degree of bone marrow failure and an intrinsic propensity to thromboembolic events. The disease is markedly invalidating, with chronic symptoms requiring supportive therapy – usually including periodical transfusions; possible life-threatening complications may also ensue. The biology of PNH has been progressively elucidated in the past few years, but therapeutic strategies remained unsatisfactory for decades, the only exception being stem cell transplantation, which is restricted to selected patients and retains significant morbidity and mortality. Recently, a biological agent to treat PNH has been developed – the terminal complement inhibitor eculizumab – which has been tested in a number of clinical trials, with exciting results. All the data from worldwide clinical trials confirm that eculizumab radically modifies the symptoms, the biology, and the natural history of PNH, strongly improving the quality of life of PNH patients.
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Affiliation(s)
- Antonio M Risitano
- Hematology, Department of Biochemistry and Medical Biotechnologies, Federico II, University of Naples, Italy
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16
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Pulini S, Marando L, Natale A, Pascariello C, Catinella V, Del Vecchio L, Risitano AM, Fioritoni G. Paroxysmal nocturnal hemoglobinuria after autologous stem cell transplantation: extinction of the clone during treatment with eculizumab - pathophysiological implications of a unique clinical case. Acta Haematol 2011; 126:103-9. [PMID: 21597283 DOI: 10.1159/000327251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 02/24/2011] [Indexed: 11/19/2022]
Abstract
The clinical and biological spectrum of paroxysmal nocturnal hemoglobinuria (PNH) is variable, ranging from classical hemolytic forms to PNH associated with aplastic anemia or other bone marrow (BM) failure syndromes. We report a previously undescribed case of PNH occurring after autologous stem cell transplantation (ASCT) in a patient affected by relapsing non-Hodgkin's lymphoma. The intensive chemotherapy and the ASCT resulted in a contraction of the effective hematopoietic stem cell (HSC) pool and a derangement of the immune system. The delayed engraftment and the BM hypoplasia represented a favorable environment for the expansion of the pathological clone. This case is paradigmatic even for the unexpected trend of the PNH clone during treatment with the terminal complement inhibitor eculizumab; in fact, the clone reduced until undergoing unexpected extinction, i.e. the recovery of normal hematopoiesis. Eculizumab seems not to play a direct role in HSC kinetics; the clinical remission probably occurred because the environmental conditions that led to the expansion of the PNH clone were transient and disappeared.
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Affiliation(s)
- Stefano Pulini
- Department of Hematology, Spirito Santo Hospital, Pescara, Italy.
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17
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Visconte V, Raghavachari N, Liu D, Keyvanfar K, Desierto MJ, Chen J, Young NS. Phenotypic and functional characterization of a mouse model of targeted Pig-a deletion in hematopoietic cells. Haematologica 2009; 95:214-23. [PMID: 19679885 DOI: 10.3324/haematol.2009.011650] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Somatic mutation in the X-linked phosphatidylinositol glycan class A gene (PIG-A) causes glycosyl phosphatidylinositol anchor deficiency in human patients with paroxysmal nocturnal hemoglobinuria. DESIGN AND METHODS We produced an animal model of paroxysmal nocturnal hemoglobinuria by conditional Pig-a gene inactivation (Pig-a(-/-)) in hematopoietic cells; mice carrying two lox sites flanking exon 6 of the Pig-a gene were bred with mice carrying the transgene Cre-recombinase under the human c-fes promoter. We characterized the phenotypic and functional properties of glycosyl phosphatidylinositol-deficient and glycosyl phosphatidylinositol-normal hematopoietic cells from these Pig-a(-/-) mice using gene expression microarray, flow cytometry, bone marrow transplantation, spectratyping, and immunoblotting. RESULTS In comparison to glycosyl phosphatidylinositol-normal bone marrow cells, glycosyl phosphatidylinositol-deficient bone marrow cells from the same Pig-a(-/-) animals showed up-regulation of the expression of immune function genes and contained a significantly higher proportion of CD8 T cells. Both characteristics were maintained when glycosyl phosphatidylinositol-deficient cells were transplanted into lethally-irradiated recipients. Glycosyl phosphatidylinositol-deficient T cells were inactive, showed pronounced Vbeta5.1/5.2 skewing, had fewer gamma-interferon-producing cells after lectin stimulation, and contained fewer CD4(+)CD25(+)FoxP3(+) regulatory T cells. However, the levels of T-cell receptor signaling proteins from glycosyl phosphatidylinositol-deficient cells were normal relative to glycosyl phosphatidylinositol-normal cells from wild type animals, and cells were capable of inducing target cell apoptosis in vitro. CONCLUSIONS Deletion of the Pig-a gene in hematopoietic cells does not cause frank marrow failure but leads to the appearance of clonally-restricted, inactive yet functionally competent CD8 T cells.
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Affiliation(s)
- Valeria Visconte
- Hematology Branch, NHLBI, National Institutes of Health, Bethesda, MD 20892-1202 USA.
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18
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Young NS. Paroxysmal nocturnal hemoglobinuria and myelodysplastic syndromes: clonal expansion of PIG-A-mutant hematopoietic cells in bone marrow failure. Haematologica 2009; 94:3-7. [PMID: 19118373 DOI: 10.3324/haematol.2008.001297] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
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19
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Savage WJ, Barber JP, Mukhina GL, Hu R, Chen G, Matsui W, Thoburn C, Hess AD, Cheng L, Jones RJ, Brodsky RA. Glycosylphosphatidylinositol-anchored protein deficiency confers resistance to apoptosis in PNH. Exp Hematol 2008; 37:42-51. [PMID: 19013003 DOI: 10.1016/j.exphem.2008.09.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 08/28/2008] [Accepted: 09/02/2008] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Investigate the contribution of PIG-A mutations to clonal expansion in paroxysmal nocturnal hemoglobinuria (PNH). MATERIALS AND METHODS Primary CD34+ hematopoietic progenitors from PNH patients were assayed for annexin-V positivity by flow cytometry in a cell-mediated killing assay using autologous effectors from PNH patients or allogeneic effectors from healthy controls. To specifically assess the role of the PIG-A mutation in the development of clonal dominance and address confounders of secondary mutation and differential immune attack that can confound experiments using primary cells, we established an inducible PIG-A CD34+ myeloid cell line, TF-1. Apoptosis resistance was assessed after exposure to allogeneic effectors, NK92 cells (an interleukin-2-dependent cell line with the phenotype and function of activated natural killer [NK] cells), tumor necrosis factor (TNF)-alpha, and gamma-irradiation. Apoptosis was measured by annexin-V staining and caspase 3/7 activity. RESULTS In PNH patients, CD34+ hematopoietic progenitors lacking glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-AP(-)) were less susceptible than GPI-AP+ CD34+ precursors to autologous (8% vs 49%; p < 0.05) and allogeneic (28% vs 58%; p < 0.05) cell-mediated killing from the same patients. In the inducible PIG-A model, GPI-AP(-) TF-1 cells exhibited less apoptosis than induced, GPI-AP+ TF-1 cells in response to allogeneic cell-mediated killing, NK92-mediated killing, TNF-alpha, and gamma-irradiation. GPI-AP(-) TF-1 cells maintained resistance to apoptosis when effectors were raised against GPI-AP(-) cells, arguing against a GPI-AP being the target of immune attack in PNH. NK92-mediated killing was partially inhibited with blockade by specific antibodies to the stress-inducible GPI-AP ULBP1 and ULBP2 that activate immune effectors. Clonal competition experiments demonstrate that the mutant clone expands over time under proapoptotic conditions with TNF-alpha. CONCLUSION PIG-A mutations contribute to clonal expansion in PNH by conferring a survival advantage to hematopoietic progenitors under proapoptotic stresses.
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Affiliation(s)
- William J Savage
- Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196, USA
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20
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Hernández-Campo PM, Almeida J, Orfao A. Hemoglobinuria paroxística nocturna. Med Clin (Barc) 2008; 131:617-30. [DOI: 10.1157/13127921] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Baerlocher GM, Sloand EM, Young NS, Lansdorp PM. Telomere length in paroxysmal nocturnal hemoglobinuria correlates with clone size. Exp Hematol 2007; 35:1777-81. [PMID: 17697745 DOI: 10.1016/j.exphem.2007.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 06/05/2007] [Accepted: 06/06/2007] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To study if telomere length can be used as a surrogate marker for the mitotic history in normal and affected hematopoietic cells from patients with paroxysmal nocturnal hemoglobinuria (PNH). METHODS The telomere length was measured by automated multicolor flow fluorescence in situ hybridization in glycosyl-phosphatidyl-inositol anchored protein (GPI)-negative and GPI-positive peripheral blood leukocytes. Eleven patients were studied, two with predominantly hemolytic PNH and nine with PNH associated with marrow failure. RESULTS Telomere length in GPI-negative cells was significantly shorter than in GPI-positive cells of the same patient (p < 0.01, n = 11). The difference in telomere length (telomere length in GPI-positive minus telomere length in GPI-negative cells) correlated with the percentage of GPI-negative white blood cells. CONCLUSION Our results support the hypothesis that telomere length is correlated to the replicative history of GPI-positive and GPI-negative cells and warrant further studies of telomere length in relation to disease progression in PNH.
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22
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Stern M, Buser AS, Lohri A, Tichelli A, Nissen-Druey C. Autoimmunity and malignancy in hematology—More than an association. Crit Rev Oncol Hematol 2007; 63:100-10. [PMID: 17391977 DOI: 10.1016/j.critrevonc.2007.02.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 01/02/2007] [Accepted: 02/06/2007] [Indexed: 02/01/2023] Open
Abstract
Several associations between hematological malignancies and autoimmunity directed against hematopoietic cells exist. Antibody mediated elimination of mature blood cells such as autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) are frequent complications of non-Hodgkin lymphomas, most prominently chronic lymphocytic leukemia. Autoimmunity directed against hematopoietic precursor cells is the hallmark of aplastic anemia, but many features of this disease are shared by two related disorders, paroxysmal nocturnal hemoglobinuria (PNH) and myelodysplastic syndrome (MDS). While the clinical associations between hematological malignancy and autoimmunity have been described many decades ago, only in the last several years have the common pathogenetic mechanisms been elucidated. We summarize the recent progress made in understanding how hematological malignancy gives rise to autoimmunity directed against blood cells and vice versa, and illustrate parallels in the etiology of malignant and autoimmune hematological disorders. Specifically, recent progress in the recognition of the association of lymphoproliferative disorders and autoimmunity against mature blood cells, and common pathogenetic background of aplastic anemia, paroxysmal nocturnal hemoglobinuria, and myelodysplastic syndrome are discussed.
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Affiliation(s)
- Martin Stern
- Division of Experimental Hematology and Clinical Immunology, Department of Clinical and Experimental Medicine, University of Perugia, Policlinico Monteluce, Perugia, Italy
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23
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Young NS, Calado RT, Scheinberg P. Current concepts in the pathophysiology and treatment of aplastic anemia. Blood 2006; 108:2509-19. [PMID: 16778145 PMCID: PMC1895575 DOI: 10.1182/blood-2006-03-010777] [Citation(s) in RCA: 622] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aplastic anemia, an unusual hematologic disease, is the paradigm of the human bone marrow failure syndromes. Almost universally fatal just a few decades ago, aplastic anemia can now be cured or ameliorated by stem-cell transplantation or immunosuppressive drug therapy. The pathophysiology is immune mediated in most cases, with activated type 1 cytotoxic T cells implicated. The molecular basis of the aberrant immune response and deficiencies in hematopoietic cells is now being defined genetically; examples are telomere repair gene mutations in the target cells and dysregulated T-cell activation pathways. Immunosuppression with antithymocyte globulins and cyclosporine is effective at restoring blood-cell production in the majority of patients, but relapse and especially evolution of clonal hematologic diseases remain problematic. Allogeneic stem-cell transplant from histocompatible sibling donors is curative in the great majority of young patients with severe aplastic anemia; the major challenges are extending the benefits of transplantation to patients who are older or who lack family donors. Recent results with alternative sources of stem cells and a variety of conditioning regimens to achieve their engraftment have been promising, with survival in small pediatric case series rivaling conventional transplantation results.
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Affiliation(s)
- Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute/NIH, 10 Center Drive, Bldg 10/CRC, Rm 3E-5140, Bethesda, MD 20892-1202, USA.
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24
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Luzzatto L. Paroxysmal nocturnal hemoglobinuria: an acquired X-linked genetic disease with somatic-cell mosaicism. Curr Opin Genet Dev 2006; 16:317-22. [PMID: 16650759 DOI: 10.1016/j.gde.2006.04.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2006] [Accepted: 04/18/2006] [Indexed: 12/30/2022]
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a severe hemolytic anemia caused by an intrinsic abnormality of the red blood cells that makes them exceedingly susceptible to the lytic action of activated complement (C). This abnormality results from a mutation in the PIG-A gene on Xp22. Given that the mutation is not inherited but is somatically acquired by a hematopoietic stem cell, it creates two populations of blood cells: normal cells and PNH cells. The clinical expression of PNH depends on the relative and absolute expansion of the PNH cell population, which probably depends, in turn, on a paradoxical growth advantage conferred to it by the existence in the patients of an autoimmune process that exerts negative selection against the 'normal' hematopoietic stem cells.
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Affiliation(s)
- Lucio Luzzatto
- University of Genova Scientific Director Istituto Toscano Tumori, Via Taddeo Alderotti 26N, 50139 Firenze, Italy.
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25
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Muller-Sieburg CE, Sieburg HB. The GOD of hematopoietic stem cells: a clonal diversity model of the stem cell compartment. Cell Cycle 2006; 5:394-8. [PMID: 16479167 PMCID: PMC1464375 DOI: 10.4161/cc.5.4.2487] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Hematopoietic stem cells (HSC) show heterogeneous behavior even when isolated as phenotypically homogeneous populations. The cellular and molecular mechanisms that control the generation of diversity (GOD) in the HSC compartment are not well understood, but have been the focus of much debate. There is increasing evidence that the most important HSC functions, self-renewal and differentiation, are epigenetically preprogrammed and therefore predictable. Indeed, recent data show that the adult HSC compartment consists of a limited number of functionally distinct subsets of HSC. This contradicts older models of HSC behavior, which postulated a single type of HSC that can be continuously molded into different subtypes of HSC. We propose a clonal diversity model where the adult HSC compartment consists of a fixed number of different types of HSC, each with epigenetically preprogrammed behavior. Aging or disease may change the overall function of the HSC population. The model predicts that these changes reflect the relative composition of the HSC subsets, rather than changes in individual HSC. This view has implications for using HSC in experimental and clinical settings. Selection for the appropriate subsets of HSC, rather than attempts to force HSC to adjust, should improve their utility in transplantation and gene transfer applications.
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26
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Abstract
Functional failure in hematopoietic stem cells (HSCs) may bring fatal consequences because HSCs are the ultimate source of mature blood cells, which need continuous replenishment. One potential cause of HSC dysfunction is senescence, in which HSCs and progenitor cells enter a state of proliferative arrest. HSC senescence is genetically regulated and one particular regulator is the telomerase gene. Mutations in the telomerase gene complex have been found in patients with bone marrow failure syndromes. During a normal lifetime, HSC clones function over the long term and may not show any functional loss under normal circumstances. However, pathologic environments may limit HSC proliferation, accelerate HSC turnover, and shorten the functional life of HSCs, leading to HSC clonal exhaustion and senescence.
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Affiliation(s)
- Jichun Chen
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1202, USA.
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27
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Young NS. Pathophysiologic mechanisms in acquired aplastic anemia. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2006:72-7. [PMID: 17124043 DOI: 10.1182/asheducation-2006.1.72] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Aplastic anemia, an unusual hematologic disease, is the paradigm of the human bone marrow failure syndromes. Absence of hematopoietic cells has been recognized from the characteristic morphology for a century; an immune pathophysiology has been inferred from improvement in blood counts with immunosuppressive therapy in the majority of patients. Molecular mechanisms underlying both T cell effector cells and the target marrow stem and progenitor cells are now being identified. Activated type 1 cytotoxic T cells and type 1 cytokines have been implicated in cell culture experiments; clues to the molecular basis of the aberrant immune response include cytokine gene polymorphisms and abnormalities in the regulatory pathways for gamma-interferon. For stem cell depletion, mutations in genes of the telomere repair complex are present in some patients with apparently acquired aplastic anemia. Telomerase deficiency is associated with short telomeres and a quantitative reduction in marrow progenitors and likely also a qualitative deficiency in the repair capacity of hematopoietic tissue.
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Affiliation(s)
- Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20891, USA.
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28
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Zeng W, Miyazato A, Chen G, Kajigaya S, Young NS, Maciejewski JP. Interferon-gamma-induced gene expression in CD34 cells: identification of pathologic cytokine-specific signature profiles. Blood 2005; 107:167-75. [PMID: 16131564 PMCID: PMC1895358 DOI: 10.1182/blood-2005-05-1884] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Hematopoietic effects of interferon-gamma (IFN-gamma) may be responsible for certain aspects of the pathology seen in bone marrow failure syndromes, including aplastic anemia (AA), paroxysmal nocturnal hemoglobinuria (PNH), and some forms of myelodysplasia (MDS). Overexpression of and hematopoietic inhibition by IFN-gamma has been observed in all of these conditions. In vitro, IFN-gamma exhibits strong inhibitory effects on hematopoietic progenitor and stem cells. Previously, we have studied the transcriptome of CD34 cells derived from patients with bone marrow failure syndromes and identified characteristic molecular signatures common to some of these conditions. In this report, we have investigated genome-wide expression patterns after exposure of CD34 and bone marrow stroma cells derived from normal bone marrow to IFN-gamma in vitro and have detected profound changes in the transcription profile. Some of these changes were concordant in both stroma and CD34 cells, whereas others were specific to CD34 cells. In general, our results were in agreement with the previously described function of IFN-gamma in CD34 cells involving activation of apoptotic pathways and immune response genes. Comparison between the IFN-gamma transcriptome in normal CD34 cells and changes previously detected in CD34 cells from AA and PNH patients reveals the presence of many similarities that may reflect molecular signature of in vivo IFN-gamma exposure.
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Affiliation(s)
- Weihua Zeng
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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