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De Clercq E. The magic of a methyl group: Biochemistry at the service of medicine. Biochem Pharmacol 2023; 216:115786. [PMID: 37660830 DOI: 10.1016/j.bcp.2023.115786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/05/2023]
Abstract
A carbon-carbon linkage is created when a methyl group is implanted on dUMP, thus resulting in the formation of dTMP by thymidylate synthase. The methyl group is deleted by aromatase when androgens are converted to estrogens. The methyl group is rearranged with the help of vitamin B12 in the isomerization of methylmalonyl-CoA to succinyl-CoA. S-adenosylmethionine (SAM) serves as the universal methyl donor involved in the biosynthesis of adrenaline and creatine(phosphate). It also interferes with the 5'-mRNA capping and the degradation of catecholamines (i.e. adrenaline, noradrenaline). Cholesterol could be viewed as a conglomeration of methyl groups. Finally, as part of valine, two methyl functions participate in the origin of one of the most frequent hereditary diseases on earth, sickle cell anemia.
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Affiliation(s)
- Erik De Clercq
- Emeritus Professor at the KU Leuven (Belgium), Visiting Professor at the Jihočeská University of South Bohemia, České Budějovice, Czech Republic
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2
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Luzzatto L. A Journey from Blood Cells to Genes and Back. Annu Rev Genomics Hum Genet 2023; 24:1-33. [PMID: 37217201 DOI: 10.1146/annurev-genom-101022-105018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
I was attracted to hematology because by combining clinical findings with the use of a microscope and simple laboratory tests, one could often make a diagnosis. I was attracted to genetics when I learned about inherited blood disorders, at a time when we had only hints that somatic mutations were also important. It seemed clear that if we understood not only what genetic changes caused what diseases but also the mechanisms through which those genetic changes contribute to cause disease, we could improve management. Thus, I investigated many aspects of the glucose-6-phosphate dehydrogenase system, including cloning of the gene, and in the study of paroxysmal nocturnal hemoglobinuria (PNH), I found that it is a clonal disorder; subsequently, we were able to explain how a nonmalignant clone can expand, and I was involved in the first trial of PNH treatment by complement inhibition. I was fortunate to do clinical and research hematology in five countries; in all of them, I learned from mentors, from colleagues, and from patients.
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Affiliation(s)
- Lucio Luzzatto
- Department of Hematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar es Salaam, United Republic of Tanzania
- University of Florence, Florence, Italy;
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3
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Decreased parasite burden and altered host response in children with sickle cell anemia and severe anemia with malaria. Blood Adv 2021; 5:4710-4720. [PMID: 34470050 PMCID: PMC8759120 DOI: 10.1182/bloodadvances.2021004704] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/21/2021] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum malaria causes morbidity and mortality in African children with sickle cell anemia (SCA), but comparisons of host responses to P falciparum between children with SCA (homozygous sickle cell disease/hemoglobin SS [HbSS]) and normal hemoglobin genotype/hemoglobin AA (HbAA) are limited. We assessed parasite biomass and plasma markers of inflammation and endothelial activation in children with HbAA (n = 208) or HbSS (n = 22) who presented with severe anemia and P falciparum parasitemia to Mulago Hospital in Kampala, Uganda. Genotyping was performed at study completion. No child had known SCA at enrollment. Children with HbSS did not differ from children with HbAA in peripheral parasite density, but had significantly lower sequestered parasite biomass. Children with HbSS had greater leukocytosis but significantly lower concentrations of several plasma inflammatory cytokines, including tumor necrosis factor α (TNF-α). In contrast, children with HbSS had threefold greater concentrations of angiopoietin-2 (Angpt-2), a marker of endothelial dysregulation associated with mortality in severe malaria. Lower TNF-α concentrations were associated with increased risk of postdischarge mortality or readmission, whereas higher Angpt-2 concentrations were associated with increased risk of recurrent clinical malaria. Children with SCA have decreased parasite sequestration and inflammation but increased endothelial dysregulation during severe anemia with P falciparum parasitemia, which may ameliorate acute infectious complications but predispose to harmful long-term sequelae.
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4
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Sickle Cell Anemia and Babesia Infection. Pathogens 2021; 10:pathogens10111435. [PMID: 34832591 PMCID: PMC8618680 DOI: 10.3390/pathogens10111435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 02/02/2023] Open
Abstract
Babesia is an intraerythrocytic, obligate Apicomplexan parasite that has, in the last century, been implicated in human infections via zoonosis and is now widespread, especially in parts of the USA and Europe. It is naturally transmitted by the bite of a tick, but transfused blood from infected donors has also proven to be a major source of transmission. When infected, most humans are clinically asymptomatic, but the parasite can prove to be lethal when it infects immunocompromised individuals. Hemolysis and anemia are two common symptoms that accompany many infectious diseases, and this is particularly true of parasitic diseases that target red cells. Clinically, this becomes an acute problem for subjects who are prone to hemolysis and depend on frequent transfusions, like patients with sickle cell anemia or thalassemia. Little is known about Babesia's pathogenesis in these hemoglobinopathies, and most parallels are drawn from its evolutionarily related Plasmodium parasite which shares the same environmental niche, the RBCs, in the human host. In vitro as well as in vivo Babesia-infected mouse sickle cell disease (SCD) models support the inhibition of intra-erythrocytic parasite proliferation, but mechanisms driving the protection of such hemoglobinopathies against infection are not fully studied. This review provides an overview of our current knowledge of Babesia infection and hemoglobinopathies, focusing on possible mechanisms behind this parasite resistance and the clinical repercussions faced by Babesia-infected human hosts harboring mutations in their globin gene.
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Mwaiswelo RO, Mawala W, Iversen PO, de Montalembert M, Luzzatto L, Makani J. Sickle cell disease and malaria: decreased exposure and asplenia can modulate the risk from Plasmodium falciparum. Malar J 2020; 19:165. [PMID: 32334583 PMCID: PMC7183641 DOI: 10.1186/s12936-020-03212-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/28/2020] [Indexed: 11/10/2022] Open
Abstract
Background Patients with sickle cell disease (SCD), an inherited haemoglobinopathy, have increased risk of malaria, at least in part due to impaired splenic function. Infection with Plasmodium falciparum in SCD patients can trigger painful vaso-occlusive crisis, increase the severity of anaemia, and contribute to early childhood mortality. Case presentation A 17 year-old Tanzanian male with known SCD was admitted to Muhimbili National Hospital, a tertiary referral centre in Dar-es-Salaam, following an attack of malaria. From 2004 to 2007 the patient had lived in USA, and from 2010 to 2016 in France where, on account of hypersplenism and episodes of splenic sequestrations, in 2014 the spleen was removed. After appropriate clinical and laboratory assessment the patient was re-started on hydroxyurea; and anti-malarial-prophylaxis with proguanil was instituted. The patient has remained well and malaria-free for the following 15 months. Conclusion SCD patients are highly vulnerable to malaria infection, and impaired splenic function is a feature of SCD patients, even in those who still anatomically have a spleen. This patient had a surgical splenectomy and, in addition, had probably lost some of the acquired malaria-immunity by having lived for several years in malaria-free areas. This patient is a compelling reminder that long-term anti-malarial prophylaxis should be offered to all patients with SCD who live in malaria-endemic areas.
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Affiliation(s)
- Richard O Mwaiswelo
- Department of Microbiology, Immunology and Parasitology, Hubert Kairuki Memorial University, Dar es Salaam, Tanzania. .,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
| | - William Mawala
- Department of Hematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Per O Iversen
- Department of Hematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.,Department of Haematology, Oslo University Hospital, Oslo, Norway
| | - Mariane de Montalembert
- Department of General Pediatrics and Pediatric Infectious Diseases, Necker-Enfants malades Hospital, Assistance Publique-Hôpitaux de Paris, Université de Paris, Paris, France
| | - Lucio Luzzatto
- Department of Hematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Julie Makani
- Department of Hematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
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6
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Malaria. HIGHLY INFECTIOUS DISEASES IN CRITICAL CARE 2020. [PMCID: PMC7120402 DOI: 10.1007/978-3-030-33803-9_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Malaria is a significant cause of morbidity and mortality throughout the world, and environmental changes are likely to increase its importance in the coming years. Diagnosing this disease is difficult and requires a high index of suspicion, especially in non-endemic countries. Critical care providers play a major role in treating severe malaria and its complications, which has management particularities that might not be readily apparent. Fluid resuscitation should be carefully tailored to avoid complications, and dysperfusion seems more related to degree of parasitemia than hypovolemia. Antimalarial agents are effective, but resistance is growing. Complications can be found in nearly every organ, including cerebral malaria, acute respiratory distress syndrome, and acute kidney injury. As such, a critical care unit is frequently required for organ support when they appear. Superimposed infections are not infrequent. Despite all of this, mortality is encouragingly low with a timely diagnosis and access to appropriate treatment.
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Prevalence of inherited blood disorders and associations with malaria and anemia in Malawian children. Blood Adv 2019; 2:3035-3044. [PMID: 30425067 DOI: 10.1182/bloodadvances.2018023069] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/10/2018] [Indexed: 12/23/2022] Open
Abstract
In sub-Saharan Africa, inherited causes of anemia are common, but data are limited regarding the geographical prevalence and coinheritance of these conditions and their overall contributions to childhood anemia. To address these questions in Malawi, we performed a secondary analysis of the 2015-2016 Malawi Micronutrient Survey, a nationally and regionally representative survey that estimated the prevalence of micronutrient deficiencies and evaluated both inherited and noninherited determinants of anemia. Children age 6 to 59 months were sampled from 105 clusters within the 2015-2016 Malawi Demographic Health Survey. Hemoglobin, ferritin, retinol binding protein, malaria, and inflammatory biomarkers were measured from venous blood. Molecular studies were performed using dried blood spots to determine the presence of sickle cell disease or trait, α-thalassemia trait, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Of 1279 eligible children, 1071 were included in the final analysis. Anemia, iron deficiency, and malaria were common, affecting 30.9%, 21.5%, and 27.8% of the participating children, respectively. α-Thalassemia trait was common (>40% of children demonstrating deletion of 1 [33.1%] or 2 [10.0%] α-globin genes) and associated with higher prevalence of anemia (P < .001). Approximately 20% of males had G6PD deficiency, which was associated with a 1.0 g/dL protection in hemoglobin decline during malaria infection (P = .02). These data document that inherited blood disorders are common and likely play an important role in the prevalence of anemia and malaria in Malawian children.
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8
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Bachmeyer C, Steichen O, Moreno-Sabater A, Magne D, Valin N, Mattioni S, Santin A, Lionnet F. Cases of malaria in travellers with sickle cell disease - Chemoprophylaxis is important for this risk group. Travel Med Infect Dis 2019; 35:101470. [PMID: 31470113 DOI: 10.1016/j.tmaid.2019.101470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 10/26/2022]
Affiliation(s)
- Claude Bachmeyer
- Service de Médecine Interne, Centre de La Drépanocytose, Hôpital Tenon (AP-HP), Paris, France.
| | - Olivier Steichen
- Service de Médecine Interne, Centre de La Drépanocytose, Hôpital Tenon (AP-HP), Paris, France
| | - Alicia Moreno-Sabater
- Sorbonne Université, Inserm U1135, CNRS ELR 8255, Centre D'Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, Service de Parasitologie-Mycologie, AP-HP. Hôpital Saint Antoine, Paris, France
| | - Denis Magne
- Sorbonne Université, Inserm U1135, CNRS ELR 8255, Centre D'Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, Service de Parasitologie-Mycologie, AP-HP. Hôpital Saint Antoine, Paris, France
| | - Nadia Valin
- Service de Maladies Infectieuses et Tropicales, AP-HP. Hôpital Saint Antoine, 75012, Paris, France
| | - Sarah Mattioni
- Service de Médecine Interne, Centre de La Drépanocytose, Hôpital Tenon (AP-HP), Paris, France
| | - Aline Santin
- Service de Médecine Interne, Centre de La Drépanocytose, Hôpital Tenon (AP-HP), Paris, France
| | - François Lionnet
- Service de Médecine Interne, Centre de La Drépanocytose, Hôpital Tenon (AP-HP), Paris, France
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9
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Cursino-Santos JR, Singh M, Senaldi E, Manwani D, Yazdanbakhsh K, Lobo CA. Altered parasite life-cycle processes characterize Babesia divergens infection in human sickle cell anemia. Haematologica 2019; 104:2189-2199. [PMID: 30923098 PMCID: PMC6821620 DOI: 10.3324/haematol.2018.214304] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/20/2019] [Indexed: 01/08/2023] Open
Abstract
Babesia divergens is an intra-erythrocytic parasite that causes malaria-like symptoms in infected people. As the erythrocyte provides the parasite with the infra-structure to grow and multiply, any perturbation to the cell should impact parasite viability. Support for this comes from the multitude of studies that have shown that the sickle trait has in fact been selected because of the protection it provides against a related Apicomplexan parasite, Plasmodium, that causes malaria. In this paper, we examine the impact of both the sickle cell anemia and sickle trait red blood cell (RBC) environment on different aspects of the B. divergens life-cycle, and reveal that multiple aspects of parasite biological processes are altered in the mutant sickle anemia RBC. Such processes include parasite population progression, caused potentially by defective merozoite infectivity and/or defective egress from the sickle cell, resulting in severely lowered parasitemia in these cells with sickle cell anemia. In contrast, the sickle trait RBC provide a supportive environment permitting in vitro infection rates comparable to those of wild-type RBC. The elucidation of these naturally occurring RBC resistance mechanisms is needed to shed light on host-parasite interaction, lend evolutionary insights into these related blood-borne parasites, and to provide new insights into the development of therapies against this disease.
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Affiliation(s)
- Jeny R Cursino-Santos
- Department of Blood-Borne Parasites Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY
| | - Manpreet Singh
- Department of Blood-Borne Parasites Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY
| | - Eric Senaldi
- Medical Services New York Blood Center, New York, NY
| | - Deepa Manwani
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY
| | - Karina Yazdanbakhsh
- Department of Complement Biology Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, USA
| | - Cheryl A Lobo
- Department of Blood-Borne Parasites Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY
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10
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Abstract
Advances in human genome editing, in particular the development of the clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 method, have led to increasing concerns about the ethics of editing the human genome. In response, the US National Academy of Sciences and the National Academy of Medicine constituted a multidisciplinary, international committee to review the current status and make recommendations. I was a member of that committee, and the core of this review reflects the committee's conclusions. The committee's report, issued in February 2017, recommends the application of current ethical and regulatory standards for gene therapy to somatic (nonheritable) human genome editing. It also recommends allowing experimental germline genome editing to proceed if ( a) it is restricted to preventing transmission of a serious disease or condition, ( b) the edit is a modification to a common DNA sequence known not to be associated with disease, and ( c) the research is conducted under a stringent set of ethical and regulatory requirements. Crossing the so-called red line of germline genome editing raises important bioethical issues, most importantly, serious concern about the potential negative impact on individuals with disabilities. This review highlights some of the major ethical considerations in human genome editing in light of the report's recommendations.
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Affiliation(s)
- Barry S Coller
- Allen and Frances Adler Laboratory of Blood and Vascular Biology, Rockefeller University, New York, NY 10065, USA;
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11
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Martins R, Carlos AR, Braza F, Thompson JA, Bastos-Amador P, Ramos S, Soares MP. Disease Tolerance as an Inherent Component of Immunity. Annu Rev Immunol 2019; 37:405-437. [PMID: 30673535 DOI: 10.1146/annurev-immunol-042718-041739] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pathogenic organisms exert a negative impact on host health, revealed by the clinical signs of infectious diseases. Immunity limits the severity of infectious diseases through resistance mechanisms that sense and target pathogens for containment, killing, or expulsion. These resistance mechanisms are viewed as the prevailing function of immunity. Under pathophysiologic conditions, however, immunity arises in response to infections that carry health and fitness costs to the host. Therefore, additional defense mechanisms are required to limit these costs, before immunity becomes operational as well as thereafter to avoid immunopathology. These are tissue damage control mechanisms that adjust the metabolic output of host tissues to different forms of stress and damage associated with infection. Disease tolerance is the term used to define this defense strategy, which does not exert a direct impact on pathogens but is essential to limit the health and fitness costs of infection. Under this argument, we propose that disease tolerance is an inherent component of immunity.
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Affiliation(s)
- Rui Martins
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal;
| | | | - Faouzi Braza
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal;
| | | | | | - Susana Ramos
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal;
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12
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Wang C, Bauckman KA, Ross ASB, Symington JW, Ligon MM, Scholtes G, Kumar A, Chang HW, Twentyman J, Fashemi BE, Xavier RJ, Mysorekar IU. A non-canonical autophagy-dependent role of the ATG16L1 T300A variant in urothelial vesicular trafficking and uropathogenic Escherichia coli persistence. Autophagy 2018; 15:527-542. [PMID: 30335568 DOI: 10.1080/15548627.2018.1535290] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
50% of Caucasians carry a Thr300Ala variant (T300A) in the protein encoded by the macroautophagy/autophagy gene ATG16L1. Here, we show that the T300A variant confers protection against urinary tract infections (UTIs), the most common infectious disease in women. Using knockin mice carrying the human T300A variant, we show that the variant limits the UTI-causing bacteria, uropathogenic Escherichia coli (UPEC), from establishing persistent intracellular reservoirs, which can seed UTI recurrence. This phenotype is recapitulated in mice lacking Atg16l1 or Atg7 exclusively in the urothelium. We further show that mice with the T300A variant exhibit urothelial cellular abnormalities, including vesicular congestion and aberrant accumulation of UPK (uroplakin) proteins. Importantly, presence of the T300A variant in humans is associated with similar urothelial architectural abnormalities, indicating an evolutionarily conserved impact. Mechanistically, we show that the reduced bacterial persistence is independent of basal autophagic flux or proinflammatory cytokine responses and does not involve Atg14 or Epg5. However, the T300A variant is associated with increased expression of the small GTPase Rab33b; RAB33B interacts with ATG16L1, as well as other secretory RABs, RAB27B and RAB11A, important for UPEC exocytosis from the urothelium. Finally, inhibition of secretory RABs in bladder epithelial cells increases intracellular UPEC load. Together, our results reveal that UPEC selectively utilize genes important for autophagosome formation to persist in the urothelium, and that the presence of the T300A variant in ATG16L1 is associated with changes in urothelial vesicle trafficking, which disrupts the ability of UPEC to persist, thereby limiting the risk of recurrent UTIs. Abbreviations: 3-PEHPC: 3-pyridinyl ethylidene hydroxyl phosphonocarboxylate; ATG: autophagy; ATG16L1: autophagy related 16 like 1; BECs: bladder epithelial cells; dpi: days post infection; hpi: hours post infection; IF: immunofluorescence; IL1B: interleukin 1 beta; IL6: interleukin 6; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MVB: multivesicular bodies; T300A: Thr300Ala; TNF: tumor necrosis factor; QIR(s): quiescent intracellular reservoir(s); siRNA: short interfering RNA; UPEC: uropathogenic Escherichia coli; UTI(s): urinary tract infection(s); TEM: transmission electron microscopy; WT: wild type.
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Affiliation(s)
- Caihong Wang
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Kyle A Bauckman
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Adam S B Ross
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Jane W Symington
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Marianne M Ligon
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Gael Scholtes
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Akhil Kumar
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Hao-Wei Chang
- b Pathology and Immunology , Washington University School of Medicine , St. Louis , MO , USA
| | - Joy Twentyman
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Bisiayo E Fashemi
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA
| | - Ramnik J Xavier
- c Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA
| | - Indira U Mysorekar
- a Department of Obstetrics and Gynecology , Washington University School of Medicine , St. Louis , MO , USA.,b Pathology and Immunology , Washington University School of Medicine , St. Louis , MO , USA
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13
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Ziyab AH, Hankinson J, Ewart S, Schauberger E, Kopec-Harding K, Zhang H, Custovic A, Arshad H, Simpson A, Karmaus WJ. Epistasis between FLG and IL4R Genes on the Risk of Allergic Sensitization: Results from Two Population-Based Birth Cohort Studies. Sci Rep 2018; 8:3221. [PMID: 29459738 PMCID: PMC5818621 DOI: 10.1038/s41598-018-21459-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 02/05/2018] [Indexed: 11/12/2022] Open
Abstract
Immune-specific genes as well as genes responsible for the formation and integrity of the epidermal barrier have been implicated in the pathogeneses of allergic sensitization. This study sought to determine whether an epistatic effect (gene-gene interaction) between genetic variants within interleukin 4 receptor (IL4R) and filaggrin (FLG) genes predispose to the development of allergic sensitization. Data from two birth cohort studies were analyzed, namely the Isle of Wight (IOW; n = 1,456) and the Manchester Asthma and Allergy Study (MAAS; n = 1,058). In the IOW study, one interaction term (IL4R rs3024676 × FLG variants) showed statistical significance (interaction term: P = 0.003). To illustrate the observed epistasis, stratified analyses were performed, which showed that FLG variants were associated with allergic sensitization only among IL4R rs3024676 homozygotes (OR, 1.97; 95% CI, 1.27–3.05; P = 0.003). In contrast, FLG variants effect was masked among IL4R rs3024676 heterozygotes (OR, 0.53; 95% CI, 0.22–1.32; P = 0.175). Similar results were demonstrated in the MAAS study. Epistasis between immune (IL4R) and skin (FLG) regulatory genes exist in the pathogenesis of allergic sensitization. Hence, genetic susceptibility towards defective epidermal barrier and deviated immune responses could work together in the development of allergic sensitization.
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Affiliation(s)
- Ali H Ziyab
- Department of Community Medicine and Behavioral Sciences, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait.
| | - Jenny Hankinson
- Division of Infection, Immunity and Respiratory Medicine, Manchester Academic Health Science Centre, The University of Manchester, Manchester University NHS Foundation Trust, Manchester, UK
| | - Susan Ewart
- College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Eric Schauberger
- Division of Allergy and Immunology, Cincinnati Children's Hospital, Cincinnati, OH, USA
| | - Kamilla Kopec-Harding
- Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, University of Manchester, University Hospital of South Manchester NHS Foundation Trust, Manchester, UK
| | - Hongmei Zhang
- Division of Epidemiology, Biostatistics and Environmental Health, School of Public Health, University of Memphis, Memphis, TN, USA
| | - Adnan Custovic
- Department of Paediatrics, Imperial College London, London, UK
| | - Hasan Arshad
- David Hide Asthma and Allergy Research Centre, St Mary's Hospital, Isle of Wight, UK.,Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Angela Simpson
- Division of Infection, Immunity and Respiratory Medicine, Manchester Academic Health Science Centre, The University of Manchester, Manchester University NHS Foundation Trust, Manchester, UK
| | - Wilfried J Karmaus
- Division of Epidemiology, Biostatistics and Environmental Health, School of Public Health, University of Memphis, Memphis, TN, USA
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14
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Affiliation(s)
- Lucio Luzzatto
- From the Department of Hematology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania (L.L.); and the Department of Oncology, Biochemistry Unit, University of Turin, Turin, Italy (P.A.)
| | - Paolo Arese
- From the Department of Hematology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania (L.L.); and the Department of Oncology, Biochemistry Unit, University of Turin, Turin, Italy (P.A.)
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15
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Red blood cells release microparticles containing human argonaute 2 and miRNAs to target genes of Plasmodium falciparum. Emerg Microbes Infect 2017; 6:e75. [PMID: 28831191 PMCID: PMC5583671 DOI: 10.1038/emi.2017.63] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/19/2017] [Accepted: 06/11/2017] [Indexed: 12/11/2022]
Abstract
Red blood cells (RBCs) are known to function as a refuge for providing food resources and as a shelter against the host’s immune system after malaria parasite (Plasmodium) infection. Recent studies have reported significant production of extracellular vesicles (microparticles, MPs) in the circulation of malaria patients. However, it is unclear how these extracellular vesicles are generated and what their biological functions are. In this study, we isolated the MPs from a culture medium of normal RBCs and malaria parasite-infected RBCs (iRBCs), compared their quantity and origins, and profiled their miRNAs by deep sequencing. We found a much larger number of MPs released in the culture of iRBCs than in the culture of normal RBCs. Further investigation indicated that, in these MPs, human argonaute 2 (hAgo2) was found to bind to hundreds of miRNAs. These hAgo2-miRNA complexes were transferred into the parasites, and the expression of an essential malaria antigen, PfEMP1, was downregulated by miR-451/140 through its binding to the A and B subgroups of var genes, a family of genes encoding PfEMP1. Our data suggest for the first time that, through the release of MPs, mature RBCs present an innate resistance to malaria infection. These studies also shed new light on the reason why RBCs’ genetic mutation occurs mainly in populations living in intensive malaria endemic areas and on the possibility of using miRNAs as novel medicines for malaria patients.
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16
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Kormann R, Jannot AS, Narjoz C, Ribeil JA, Manceau S, Delville M, Joste V, Prié D, Pouchot J, Thervet E, Courbebaisse M, Arlet JB. Roles of APOL1 G1 and G2 variants in sickle cell disease patients: kidney is the main target. Br J Haematol 2017; 179:323-335. [PMID: 28699644 DOI: 10.1111/bjh.14842] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/28/2017] [Indexed: 12/29/2022]
Abstract
In African-American patients with sickle cell disease (SCD), APOL1 G1 and G2 variants are associated with increased risk of sickle cell nephropathy (SCN). To determine the role of APOL1 variants in SCD patients living in Europe, we genotyped 152 SCD patients [aged 30·4 (24·3-36·4) years], mainly of Sub-Saharan African ancestry, for APOL1 G1 and G2 and for variants of four genes with kidney tropism (GSTM1, GSTT1, GSTP1, and HMOX1). Homozygous or double-heterozygous APOL G1 and G2 genotypes were strongly associated with end stage renal disease (P = 0·003) and worse Kidney Disease: Improving Global Outcomes stages (P = 0·001). Further, these genotypes were associated in an age-dependent manner with lower estimated glomerular filtration rate (eGFR, P = 0·008), proteinuria (P = 0·009) and albuminuria (P < 0·001) but not with other SCD complications. Compared to APOL1 G1/wild type (WT), the APOL1 G2/WT genotype was associated with a lower eGFR (P = 0·04) in an age-dependent manner, suggesting that the G2/WT patients are likely to have worse kidney prognosis. Other genes variants analysed were not associated with SCN or other SCD complications. Our data indicate that APOL1 screening should be considered for the management of SCD patients, including those of non-African-American origin, as those with homozygous or double heterozygous variants are clearly at higher risk of SCN.
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Affiliation(s)
- Raphaël Kormann
- Physiology Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris Descartes Faculty of Medicine, Paris, France
| | - Anne-Sophie Jannot
- Paris Descartes Faculty of Medicine, Paris, France.,INSERM UMR 1138-E22: Information Sciences & Personalized Medicine, Paris, France.,Medical Informatics, Biostatistics and Public Health Department, Georges Pompidou University Hospital, Paris, France
| | - Céline Narjoz
- Paris Descartes Faculty of Medicine, Paris, France.,Biochemistry Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) UMR-S 1147, Paris, France
| | - Jean-Antoine Ribeil
- Paris Descartes Faculty of Medicine, Paris, France.,Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Biotherapy Clinical Investigation Centre, Groupe Hospitalier Universitaire Ouest, Assistance Publique-Hôpitaux de Paris, INSERM, Paris, France.,Centre de Référence des Syndromes Drépanocytaires Majeurs, Necker-Enfants-Malades University Hospital, APHP, Université Paris 5, Paris, France
| | - Sandra Manceau
- Paris Descartes Faculty of Medicine, Paris, France.,Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Marianne Delville
- Paris Descartes Faculty of Medicine, Paris, France.,Biotherapy Department, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence des Syndromes Drépanocytaires Majeurs, Necker-Enfants-Malades University Hospital, APHP, Université Paris 5, Paris, France
| | - Valentin Joste
- Paris Descartes Faculty of Medicine, Paris, France.,Biochemistry Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Dominique Prié
- Paris Descartes Faculty of Medicine, Paris, France.,INSERM U1151-CNRS UMR8253, Paris, France.,AP-HP, Necker Children's Hospital, Physiology Department, Paris Descartes University, Paris, France
| | - Jacques Pouchot
- Paris Descartes Faculty of Medicine, Paris, France.,Internal Medicine Department, Sickle Cell Referral Centre, Faculté de Médecine Paris Descartes, Sorbonne Paris-Cité et Assistance Publique-Hôpitaux de Paris, Georges Pompidou University Hospital, Paris, France
| | - Eric Thervet
- Paris Descartes Faculty of Medicine, Paris, France.,Institut National pour la Santé et la Recherche Médicale (INSERM) UMR-S 1147, Paris, France.,Department of Nephrology, Georges Pompidou University Hospital, Assistance Publique- Hôpitaux de Paris, Paris, France
| | - Marie Courbebaisse
- Physiology Department, Georges Pompidou European Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris Descartes Faculty of Medicine, Paris, France.,INSERM U1151-CNRS UMR8253, Paris, France
| | - Jean-Benoît Arlet
- Paris Descartes Faculty of Medicine, Paris, France.,Internal Medicine Department, Sickle Cell Referral Centre, Faculté de Médecine Paris Descartes, Sorbonne Paris-Cité et Assistance Publique-Hôpitaux de Paris, Georges Pompidou University Hospital, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
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17
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Tubman VN, Makani J. Turf wars: exploring splenomegaly in sickle cell disease in malaria-endemic regions. Br J Haematol 2017; 177:938-946. [PMID: 28493472 DOI: 10.1111/bjh.14592] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sickle cell disease (SCD) is a group of recessively inherited disorders of erythrocyte function that presents an ongoing threat to reducing childhood and adult morbidity and mortality around the world. While decades of research have led to improved survival for SCD patients in wealthy countries, survival remains dismal in low- and middle-income countries. Much of the early mortality associated with SCD is attributed to increased risk of infections due to early loss of splenic function. In the West, bacterial infections with encapsulated organisms are a primary concern. In sub-Saharan Africa, where the majority of infants with SCD are born, the same is true. However malaria presents an additional threat to survival. The search for factors that define variability in sickle cell phenotypes should include environmental modifiers, such as malaria. Further exploration of this relationship could lead to novel strategies to reduce morbidity and mortality attributable to infections. In this review, we explore the interactions between SCD, malaria and the spleen to better understand how splenomegaly and splenic (dys)function may co-exist in patients with SCD living in malaria-endemic areas.
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Affiliation(s)
- Venée N Tubman
- Texas Children's Cancer and Hematology Centers, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Julie Makani
- Department of Haematology and Blood Transfusion, Muhimbili University of Health and Allied Sciences, Dar-es-salaam, Tanzania
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18
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Diakité SAS, Ndour PA, Brousse V, Gay F, Roussel C, Biligui S, Dussiot M, Prendki V, Lopera-Mesa TM, Traoré K, Konaté D, Doumbia S, Cros J, Dokmak S, Fairhurst RM, Diakité M, Buffet PA. Stage-dependent fate of Plasmodium falciparum-infected red blood cells in the spleen and sickle-cell trait-related protection against malaria. Malar J 2016; 15:482. [PMID: 27655345 PMCID: PMC5031340 DOI: 10.1186/s12936-016-1522-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/06/2016] [Indexed: 01/07/2023] Open
Abstract
Background Sickle-cell trait (HbAS) reduces falciparum malaria risk and suppresses parasitaemia. Although several candidate mechanisms have been proposed, their epidemiological, clinical and experimental correlates have not been adequately explained. To explore the basis for generally lower parasitaemias and delayed malaria episodes in children with HbAS, it is hypothesized here that their spleen-dependent removal of ring-infected red blood cells (RBCs) is more efficient than in children with normal haemoglobin A (HbAA). Methods The mechanical splenic retention of Plasmodium falciparum-infected RBCs from subjects with HbAS or HbAA was investigated using two physiologically relevant methods: microsphiltration and ex vivo spleen perfusion. P. falciparum-infected RBCs obtained from in vitro cultures and from patients were used in either normoxic or hypoxic conditions. The effect of sickling in ring-infected HbAS RBCs was also investigated. Results When a laboratory-adapted parasite strain was analysed, ring-infected HbAA RBCs were retained in microsphilters at similar or greater levels than ring-infected HbAS RBCs, under normoxic (retention rate 62.5 vs 43.8 %, P < 0.01) and hypoxic (54.0 vs 38.0 %, P = 0.11) conditions. When parasitized RBCs from Malian children were analysed, retention of ring-infected HbAA and HbAS RBCs was similar when tested either directly ex vivo (32.1 vs 28.7 %, P = 0.52) or after one re-invasion in vitro (55.9 vs 43.7 %, P = 0.30). In hypoxia, sickling of uninfected and ring-infected HbAS RBCs (8.6 vs 5.7 %, P = 0.51), and retention of ring-infected HbAA and HbAS RBCs in microsphilters (72.5 vs 68.8 %, P = 0.38) and spleens (41.2 vs 30.4 %, P = 0.11), also did not differ. Retention of HbAS and HbAA RBCs infected with mature P. falciparum stages was greater than 95 %. Conclusions Sickle-cell trait is not associated with higher retention or sickling of ring-infected RBCs in experimental systems reflecting the mechanical sensing of RBCs by the human spleen. As observed with HbAA RBCs, HbAS RBCs infected with mature parasites are completely retained. Because the cytoadherence of HbAS RBCs infected with mature parasites is impaired, the very efficient splenic retention of such non-adherent infected RBCs is expected to result in a slower rise of P. falciparum parasitaemia in sickle-cell trait carriers. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1522-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Seidina A S Diakité
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France.,Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, BP, 1805, Mali.,Laboratoire d'Excellence du Globule Rouge (GR-Ex), 75115, Paris, France
| | - Papa Alioune Ndour
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France.,Laboratoire d'Excellence du Globule Rouge (GR-Ex), 75115, Paris, France
| | - Valentine Brousse
- Centre de Référence de la Drépanocytose, Hôpital Universitaire Necker Enfants Malades, 75012, Paris, France
| | - Frederick Gay
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France
| | - Camille Roussel
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France
| | - Sylvestre Biligui
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France
| | - Michaël Dussiot
- Laboratoire d'Excellence du Globule Rouge (GR-Ex), 75115, Paris, France.,INSERM U1163/CNRS ERL 8254, Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Virginie Prendki
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France
| | - Tatiana M Lopera-Mesa
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Karim Traoré
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, BP, 1805, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, BP, 1805, Mali
| | - Saibou Doumbia
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, BP, 1805, Mali
| | - Jérôme Cros
- Department of Chirurgie Digestive et Viscérale, Hôpital Beaujon, AP-HP, 92110, Clichy, France
| | - Safi Dokmak
- Department of Chirurgie Digestive et Viscérale, Hôpital Beaujon, AP-HP, 92110, Clichy, France
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Mahamadou Diakité
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, BP, 1805, Mali
| | - Pierre A Buffet
- INSERM U1134, Paris 5, Paris 7, Institut National de la Transfusion Sanguine, 75015, Paris, France. .,Laboratoire d'Excellence du Globule Rouge (GR-Ex), 75115, Paris, France.
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19
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Berghs M, Dyson SM, Atkin K. Resignifying the sickle cell gene: Narratives of genetic risk, impairment and repair. Health (London) 2016. [DOI: 10.1177/1363459315595850] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Connecting theoretical discussion with empirical qualitative work, this article examines how sickle cell became a site of public health intervention in terms of ‘racialised’ risks. Historically, sickle cell became socio-politically allied to ideas of repair, in terms of the state improving the health of a neglected ethnic minority population. Yet, we elucidate how partial improvements in care and education arose alongside preventative public health screening efforts. Using qualitative research based in the United Kingdom, we show how a focus on collective efforts of repair can lie in tension with how services and individuals understand and negotiate antenatal screening. We illustrate how screening for sickle cell disorder calls into question narrative identity, undoing paradigms in which ethnicity, disablement and genetic impairment become framed. Research participants noted that rather than ‘choices’, it is ‘risks’ and their negotiation that are a part of discourses of modernity and the new genetics. Furthermore, while biomedical paradigms are rationally and ethically (de)constructed by participants, this was never fully engaged with by professionals, contributing to overall perception of antenatal screening as disempowering and leading to disengagement.
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20
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Patel JC, Mwapasa V, Kalilani L, Ter Kuile FO, Khairallah C, Thwai KL, Meshnick SR, Taylor SM. Absence of Association Between Sickle Trait Hemoglobin and Placental Malaria Outcomes. Am J Trop Med Hyg 2016; 94:1002-7. [PMID: 27001763 DOI: 10.4269/ajtmh.15-0672] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 01/29/2016] [Indexed: 11/07/2022] Open
Abstract
Heterozygous hemoglobin S (HbAS), or sickle trait, protects children from life-threatening falciparum malaria, potentially by attenuating binding of Plasmodium-infected red blood cells (iRBCs) to extracellular ligands. Such binding is central to the pathogenesis of placental malaria (PM). We hypothesized that HbAS would be associated with reduced risks of PM and low birth weight (LBW). We tested this hypothesis in 850 delivering women in southern Malawi. Parasites were detected by polymerase chain reaction in placental and peripheral blood, and placentae were scored histologically for PM. The prevalence of HbAS was 3.7%, and 11.2% of infants were LBW (< 2,500 g). The prevalence of Plasmodium falciparum was 12.7% in placental and 8.5% in peripheral blood; 24.4% of placentae demonstrated histological evidence of P. falciparum HbAS was not associated with reduced prevalence of P. falciparum in placental (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 0.50-3.23, P = 0.61) or peripheral blood (OR: 2.53, 95% CI: 1.08-2.54, P = 0.03), prevalence of histological PM (OR: 0.97, 95% CI: 0.40-2.34, P = 0.95), or prevalence of LBW (OR: 0.82, 95% CI: 0.24-2.73, P = 0.74). Mean (standard deviation) birth weights of infants born to HbAS (2,947 g [563]) and, homozygous hemoglobin A (2,991 g [465]) mothers were similar. Across a range of parasitologic, clinical, and histologic outcomes, HbAS did not confer protection from PM or its adverse effects.
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Affiliation(s)
- Jaymin C Patel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Victor Mwapasa
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Linda Kalilani
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Feiko O Ter Kuile
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Carole Khairallah
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Kyaw L Thwai
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
| | - Steve M Taylor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Community Health, College of Medicine, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, North Carolina
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Velasco-Rodríguez D, Alonso-Domínguez JM, González-Fernández FA, Muriel A, Abalo L, Sopeña M, Villarrubia J, Ropero P, Plaza MP, Tenorio M, Jiménez-Martín A, Moreno G, Martínez-Nieto J, de la Fuente-Gonzalo F, Fernández-Escribano M, López-Jiménez FJ, Cava F. Laboratory parameters provided by Advia 2120 analyser identify structural haemoglobinopathy carriers and discriminate between Hb S trait and Hb C trait. J Clin Pathol 2016; 69:912-20. [PMID: 26915371 DOI: 10.1136/jclinpath-2015-203556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/09/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Haemoglobinopathies have spread owing to human migration, and the number of people needing diagnosis and management of these conditions is increasing. Clinicians need to accurately identify carriers and provide adequate genetic counselling in order to prevent the occurrence of homozygous or compound heterozygous offspring. OBJECTIVES To identify red blood cell (RBC) laboratory parameters that discriminate between structural haemoglobinopathy carriers and healthy subjects, and to compare RBC laboratory indices between HbAS and HbAC individuals. METHODS Samples of 500 variant Hb carriers (355 HbAS, 104 HbAC, 19 HbAD, 7 HbAE, 7 HbAO-Arab, 4 α-chain variants and 4 Hb Lepore) and 251 normal controls were run on an Advia 2120 analyser (Siemens). Classic haematological parameters and RBC populations were assessed in all subjects. A multivariable binary logistic regression model was created to predict the probability of a subject carrying any structural haemoglobinopathy. HbAS (n=355, 71%) and HbAC (n=104, 20.8%) subjects were compared. RESULTS A clinical prediction rule was developed by assigning one point to each of the most efficient variables: mean corpuscular volume (MCV) <88.4 fL, RBC distribution width >13.4%, percentage of microcytic RBCs (%MICRO) >0.7% and the ratio of microcytic RBCs to hypochromic RBCs >0.8. A score of 0, 1, 2, 3 or 4, resulted in a probability of 9.6%, 36.3%, 66.7%, 85.2% or 98.3%, respectively. Among the most frequent variant Hb, HbAC subjects had lower values of parameters related to cell size (MCV, %MICRO) and higher values of parameters related to haemoglobin concentration (MCHC, %HYPER) than HbAS subjects. Coexistence of α-thalassaemia in both HbAS and HbAC individuals resulted in decreased Hb, MCV, MCH and MCHC. CONCLUSIONS Structural haemoglobinopathy should be investigated in subjects belonging to ethnic groups with high prevalence of variant Hb and with a score of 3 or 4. Erythrocytes of HbAC subjects are smaller and denser than those of HbAS subjects.
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Affiliation(s)
- Diego Velasco-Rodríguez
- Hospital Ramón y Cajal, Madrid, Spain Laboratorio Central de la Comunidad de Madrid, Madrid, Spain Programa de Doctorado de Investigación en Ciencias Médico-Quirúrgicas, Universidad Complutense de Madrid, Madrid, Spain
| | | | | | | | - Lorena Abalo
- Laboratorio Central de la Comunidad de Madrid, Madrid, Spain
| | - María Sopeña
- Laboratorio Central de la Comunidad de Madrid, Madrid, Spain
| | - Jesús Villarrubia
- Hospital Ramón y Cajal, Madrid, Spain Laboratorio Central de la Comunidad de Madrid, Madrid, Spain
| | | | | | | | | | | | | | | | | | | | - Fernando Cava
- Laboratorio Central de la Comunidad de Madrid, Madrid, Spain
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22
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Xu Z, Zheng Y, Wang X, Shehata N, Wang C, Xie S, Sun Y. Stiffening of sickle cell trait red blood cells under simulated strenuous exercise conditions. MICROSYSTEMS & NANOENGINEERING 2016; 2:16061. [PMID: 31057840 PMCID: PMC6444709 DOI: 10.1038/micronano.2016.61] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 07/21/2016] [Accepted: 07/21/2016] [Indexed: 05/19/2023]
Abstract
The higher risk of vaso-occlusion events and sudden death for sickle-cell trait (SCT) athletes has been speculatively ascribed to SCT red blood cell (RBC) stiffening during strenuous exercise. However, the microenvironmental changes that could induce the stiffening of SCT RBCs are unknown. To address this question, we measured the mechanical properties of and changes in SCT RBCs under deoxygenated and acidic environments, which are two typical conditions present in the circulation of athletes undertaking strenuous exercise. The results reveal that SCT RBCs are inherently stiffer than RBCs from non-SCT healthy subjects, and a lower pH further stiffens the SCT cells. Furthermore, at both normal and low pH levels, deoxygenation was found to not be the cause of the stiffness of SCT RBCs. This study confirms that the stiffening of SCT RBCs occurs at a low pH and implies that SCT RBC stiffening could be responsible for vaso-occlusion in SCT athletes during strenuous exercise.
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Affiliation(s)
- Zhensong Xu
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Yi Zheng
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Xian Wang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Nadine Shehata
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Chen Wang
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- ()
| | - Shaorong Xie
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
- ()
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
- ()
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23
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Niesor EJ, Benghozi R, Amouyel P, Ferdinand KC, Schwartz GG. Adenylyl Cyclase 9 Polymorphisms Reveal Potential Link to HDL Function and Cardiovascular Events in Multiple Pathologies: Potential Implications in Sickle Cell Disease. Cardiovasc Drugs Ther 2015; 29:563-572. [PMID: 26619842 DOI: 10.1007/s10557-015-6626-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Adenylyl cyclase 9 (ADCY9) mediates β2-adrenoceptor (β2-AR) signalling. Both proteins are associated with caveolae, specialized cholesterol-rich membrane substructures. Apolipoprotein A1 (ApoA1), the major protein component of high-density lipoprotein (HDL), removes cholesterol from cell membrane and caveolae and may thereby influence β2-AR signalling, shown in vitro to be modulated by cholesterol. Patients with Sickle Cell Disease (SCD) typically have low HDL and ApoA1 levels. In patients, mainly of African origin, with SCD, β2-AR activation may trigger adhesion of red blood cells to endothelial cells, leading to vascular occlusive events. Moreover, ADCY9 polymorphism is associated with risk of stroke in SCD. In recent clinical trials, ADCY9 polymorphism was found to be a discriminant factor associated with the risk of cardiovascular (CV) events in Caucasian patients treated with the HDL-raising compound dalcetrapib. We hypothesize that these seemingly disparate observations share a common mechanism related to interaction of HDL/ApoA1 and ADCY9 on β2-AR signalling. This review also raises the importance of characterizing polymorphisms that determine the response to HDL-raising and -mimicking agents in the non-Caucasian population at high risk of CV diseases and suffering from SCD. This may facilitate personalized CV treatments.
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Affiliation(s)
- Eric J Niesor
- F.Hoffmann-La Roche Ltd, Basel, Switzerland. .,Pre-β1 Consulting, 13c Chemin de Bonmont, 1260, Nyon, Switzerland.
| | - Renée Benghozi
- F.Hoffmann-La Roche Ltd, Basel, Switzerland.,Cerenis Therapeutics Holding, Labège, France
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Gaudreault V, Wirbel J, Jardim A, Rohrbach P, Scorza T. Red Blood Cells Preconditioned with Hemin Are Less Permissive to Plasmodium Invasion In Vivo and In Vitro. PLoS One 2015; 10:e0140805. [PMID: 26465787 PMCID: PMC4605744 DOI: 10.1371/journal.pone.0140805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 09/30/2015] [Indexed: 02/06/2023] Open
Abstract
Malaria is a parasitic disease that causes severe hemolytic anemia in Plasmodium-infected hosts, which results in the release and accumulation of oxidized heme (hemin). Although hemin impairs the establishment of Plasmodium immunity in vitro and in vivo, mice preconditioned with hemin develop lower parasitemia when challenged with Plasmodium chabaudi adami blood stage parasites. In order to understand the mechanism accounting for this resistance as well as the impact of hemin on eryptosis and plasma levels of scavenging hemopexin, red blood cells were labeled with biotin prior to hemin treatment and P. c. adami infection. This strategy allowed discriminating hemin-treated from de novo generated red blood cells and to follow the infection within these two populations of cells. Fluorescence microscopy analysis of biotinylated-red blood cells revealed increased P. c. adami red blood cells selectivity and a decreased permissibility of hemin-conditioned red blood cells for parasite invasion. These effects were also apparent in in vitro P. falciparum cultures using hemin-preconditioned human red blood cells. Interestingly, hemin did not alter the turnover of red blood cells nor their replenishment during in vivo infection. Our results assign a function for hemin as a protective agent against high parasitemia, and suggest that the hemolytic nature of blood stage human malaria may be beneficial for the infected host.
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Affiliation(s)
- Véronique Gaudreault
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Jakob Wirbel
- Institute of parasitology, McGill University, Montréal, Québec, Canada
| | - Armando Jardim
- Institute of parasitology, McGill University, Montréal, Québec, Canada
| | - Petra Rohrbach
- Institute of parasitology, McGill University, Montréal, Québec, Canada
| | - Tatiana Scorza
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Québec, Canada
- * E-mail:
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Tewari S, Brousse V, Piel FB, Menzel S, Rees DC. Environmental determinants of severity in sickle cell disease. Haematologica 2015; 100:1108-16. [PMID: 26341524 PMCID: PMC4800688 DOI: 10.3324/haematol.2014.120030] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 06/05/2015] [Indexed: 12/13/2022] Open
Abstract
Sickle cell disease causes acute and chronic illness, and median life expectancy is reduced by at least 30 years in all countries, with greater reductions in low-income countries. There is a wide spectrum of severity, with some patients having no symptoms and others suffering frequent, life-changing complications. Much of this variability is unexplained, despite increasingly sophisticated genetic studies. Environmental factors, including climate, air quality, socio-economics, exercise and infection, are likely to be important, as demonstrated by the stark differences in outcomes between patients in Africa and USA/Europe. The effects of weather vary with geography, although most studies show that exposure to cold or wind increases hospital attendance with acute pain. Most of the different air pollutants are closely intercorrelated, and increasing overall levels seem to correlate with increased hospital attendance, although higher concentrations of atmospheric carbon monoxide may offer some benefit for patients with sickle cell disease. Exercise causes some adverse physiological changes, although this may be off-set by improvements in cardiovascular health. Most sickle cell disease patients live in low-income countries and socioeconomic factors are undoubtedly important, but little studied beyond documenting that sickle cell disease is associated with decreases in some measures of social status. Infections cause many of the differences in outcomes seen across the world, but again these effects are relatively poorly understood. All the above factors are likely to account for much of the pathology and variability of sickle cell disease, and large prospective studies are needed to understand these effects better.
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Affiliation(s)
- Sanjay Tewari
- Department of Molecular Haematology, King's College London School of Medicine, King's College Hospital, London, England
| | - Valentine Brousse
- Reference Centre for Sickle Cell Disease, Pediatric Department, Hôpital Universitaire Necker-Enfants Malades, APHP, Paris; Université Paris Descartes, France
| | | | - Stephan Menzel
- Department of Molecular Haematology, King's College London School of Medicine, King's College Hospital, London, England
| | - David C Rees
- Department of Molecular Haematology, King's College London School of Medicine, King's College Hospital, London, England
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Hershberger PE, Gallo AM, Molokie R, Thompson AA, Suarez ML, Yao Y, Wilkie DJ. Perception of young adults with sickle cell disease or sickle cell trait about participation in the CHOICES randomized controlled trial. J Adv Nurs 2015; 72:1430-40. [PMID: 26073718 DOI: 10.1111/jan.12702] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2015] [Indexed: 11/29/2022]
Abstract
AIMS To gain an in-depth understanding of the perceptions of young adults with sickle cell disease and sickle cell trait about parenthood and participating in the CHOICES randomized controlled trial that used computer-based, educational programmes. BACKGROUND In the USA, there is insufficient education to assure that all young adults with sickle cell disease or sickle cell trait understand genetic inheritance risks and reproductive options to make informed reproductive decisions. To address this educational need, we developed a computer-based, multimedia program (CHOICES) and reformatted usual care into a computer-based (e-Book) program. We then conducted a two-year randomized controlled trial that included a qualitative component that would deepen understanding of young adults' perceptions of parenthood and use of computer-based, educational programmes. DESIGN A qualitative descriptive approach completed after a randomized controlled trial. METHODS Sixty-eight men and women of childbearing age participated in semi-structured interviews at the completion of the randomized controlled trial from 2012-2013. Thematic content analysis guided the qualitative description. RESULTS/FINDINGS Three main themes were identified: (1) increasing knowledge and new ways of thinking and behaving; (2) rethinking parenting plans; and (3) appraising the program design and delivery. Most participants reported increased knowledge and rethinking of their parenting plans and were supportive of computer-based learning. Some participants expressed difficulty in determining individual transmission risks. CONCLUSION Participants perceived the computer programs as beneficial to their learning. Future development of an Internet-based educational programme is warranted, with emphasis on providing tailored education or memory boosters about individual transmission risks.
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Affiliation(s)
- Patricia E Hershberger
- University of Illinois at Chicago, College of Nursing, Illinois, USA.,University of Illinois at Chicago, College of Medicine, Illinois, USA
| | - Agatha M Gallo
- University of Illinois at Chicago, College of Nursing, Illinois, USA
| | - Robert Molokie
- University of Illinois at Chicago, College of Medicine, Illinois, USA.,University of Illinois at Chicago, College of Pharmacy, Illinois, USA.,University of Illinois Hospital and Health Sciences System Comprehensive Sickle Cell Center, Chicago, Illinois, USA
| | - Alexis A Thompson
- Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA.,Division of Hematology/Oncology/Stem Cell Transplantation, Ann and Robert H. Lurie Children's Hospital of Chicago, Illinois, USA
| | - Marie L Suarez
- University of Illinois at Chicago, College of Nursing, Illinois, USA
| | - Yingwei Yao
- University of Illinois at Chicago, College of Nursing, Illinois, USA
| | - Diana J Wilkie
- University of Illinois at Chicago, College of Nursing, Illinois, USA.,University of Illinois Hospital and Health Sciences System Comprehensive Sickle Cell Center, Chicago, Illinois, USA
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Quattrone RD, Eichner ER, Beutler A, Adams WB, O’Connor FG. Exercise Collapse Associated with Sickle Cell Trait (ECAST). Curr Sports Med Rep 2015; 14:110-6. [DOI: 10.1249/jsr.0000000000000137] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Reappraisal of known malaria resistance loci in a large multicenter study. Nat Genet 2014; 46:1197-204. [PMID: 25261933 PMCID: PMC4617542 DOI: 10.1038/ng.3107] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 09/04/2014] [Indexed: 02/08/2023]
Abstract
Many human genetic associations with resistance to malaria have been reported, but few have been reliably replicated. We collected data on 11,890 cases of severe malaria due to Plasmodium falciparum and 17,441 controls from 12 locations in Africa, Asia and Oceania. We tested 55 SNPs in 27 loci previously reported to associate with severe malaria. There was evidence of association at P < 1 × 10(-4) with the HBB, ABO, ATP2B4, G6PD and CD40LG loci, but previously reported associations at 22 other loci did not replicate in the multicenter analysis. The large sample size made it possible to identify authentic genetic effects that are heterogeneous across populations or phenotypes, with a striking example being the main African form of G6PD deficiency, which reduced the risk of cerebral malaria but increased the risk of severe malarial anemia. The finding that G6PD deficiency has opposing effects on different fatal complications of P. falciparum infection indicates that the evolutionary origins of this common human genetic disorder are more complex than previously supposed.
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Campbell-Lee SA, Kittles RA. Red blood cell alloimmunization in sickle cell disease: listen to your ancestors. Transfus Med Hemother 2014; 41:431-5. [PMID: 25670930 PMCID: PMC4280449 DOI: 10.1159/000369513] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/21/2014] [Indexed: 11/19/2022] Open
Abstract
Red blood cell (RBC) alloimmunization occurs in approximately 30% of transfused sickle cell disease patients compared to 2-5% of all transfusion recipients. Because RBC transfusion is an important part of therapy in sickle cell disease, the need for additional antigen matching once alloimmunization occurs is problematic and leads to therapeutic limitations. Thus, identification of risk factors would benefit this patient population. Genome-wide analyses, in particular, methods which take into account genetic ancestry such as admixture mapping, could identify molecular markers which could be used to identify immune responders to transfusion.
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Maturation of Plasmodium falciparum in multiply infected erythrocytes and the potential role in malaria pathogenesis. Parasitol Res 2014; 113:4045-56. [DOI: 10.1007/s00436-014-4073-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/05/2014] [Indexed: 10/24/2022]
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Gonzalez-Garay ML, Cranford SM, Braun MC, Doris PA. Diversity in the preimmune immunoglobulin repertoire of SHR lines susceptible and resistant to end-organ injury. Genes Immun 2014; 15:528-33. [PMID: 25056448 PMCID: PMC4257902 DOI: 10.1038/gene.2014.40] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 04/24/2014] [Accepted: 05/23/2014] [Indexed: 01/03/2023]
Abstract
We used next-generation sequencing to identify IGH genetic variation in two closely related hypertensive rat lines that differ in susceptibility to end-organ disease (SHR-A3 and SHR-B2). The two SHR lines differ extensively at the IGH locus from the rat reference genome sequence (RRGS) and from each other, creating 306 sequence unique IGH genes. Compared to IGH genes mapped in the RRGS, 98 are null gene alleles (31 are null in both SHR lines, 45 are null in SHR-A3 only, and 23 are null in SHR-B2 only). Of the 306 divergent gene sequences, 126 result in amino acid substitution and, among these, SHR-A3 and SHR-B2 differ from one another at the amino acid level in 96 segments. Twelve pseudogenes in the RRGS had changes displacing the stop codon and creating probable functional genes in either or both SHR-A3 and SHR-B2. A further 5 alleles that encoded functional RRGS genes or open reading frames were converted to pseudogenes in either or both SHR-A3 and SHR-B2. These studies reveal that the pre-immune immunoglobulin repertoire is highly divergent among SHR lines differing in end organ injury susceptibility and this may modify immune mechanisms in hypertensive renal injury.
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Affiliation(s)
- M L Gonzalez-Garay
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - S M Cranford
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - M C Braun
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - P A Doris
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
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Matta A, Tandra PK, Berim L. Priapism in a patient with sickle cell trait using marijuana. BMJ Case Rep 2014; 2014:bcr-2014-204199. [PMID: 24798364 DOI: 10.1136/bcr-2014-204199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A 22-year-old man with a history of multiple episodes of priapism presented to the emergency room with an erection lasting more than 48 h after conservative management failed at home. He had no known family history of sickle cell disease or trait. He was haemodynamically stable. Physical examination revealed an enlarged, tender penis. Laboratory data revealed a positive sickle solubility test. Haemoglobin electrophoresis revealed sickle cell trait and urine drug screen was positive for cannabinoids. Initial management was attempted with intracavernosal phenylephrine without any success. The patient underwent a limited El-Ghorab procedure on the right corpora cavernosa but the priapism did not resolve adequately. Two days later, the patient had to undergo a bilateral El-Ghorab procedure and achieved complete resolution of the priapism.
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Affiliation(s)
- Abhishek Matta
- Department of Internal Medicine, Creighton University Medical Center, Omaha, Nebraska, USA
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Abstract
SIGNIFICANCE Inflammation and immunity can be associated with varying degrees of heme release from hemoproteins, eventually leading to cellular and tissue iron (Fe) overload, oxidative stress, and tissue damage. Presumably, these deleterious effects contribute to the pathogenesis of systemic infections. RECENT ADVANCES Heme release from hemoglobin sensitizes parenchyma cells to undergo programmed cell death in response to proinflammatory cytokines, such as tumor necrosis factor. This cytotoxic effect is driven by a mechanism involving intracellular accumulation of free radicals, which sustain the activation of the c-Jun N-terminal kinase (JNK) signaling transduction pathway. While heme catabolism by heme oxygenase-1 (HO-1) prevents programmed cell death, this cytoprotective effect requires the co-expression of ferritin H (heart/heavy) chain (FTH), which controls the pro-oxidant effect of labile Fe released from the protoporphyrin IX ring of heme. This antioxidant effect of FTH restrains JNK activation, whereas JNK activation inhibits FTH expression, a cross talk that controls metabolic adaptation to cellular Fe overload associated with systemic infections. CRITICAL ISSUES AND FUTURE DIRECTIONS Identification and characterization of the mechanisms via which FTH provides metabolic adaptation to tissue Fe overload should provide valuable information to our current understanding of the pathogenesis of systemic infections as well as other immune-mediated inflammatory diseases.
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Glushakova S, Balaban A, McQueen PG, Coutinho R, Miller JL, Nossal R, Fairhurst RM, Zimmerberg J. Hemoglobinopathic erythrocytes affect the intraerythrocytic multiplication of Plasmodium falciparum in vitro. J Infect Dis 2014; 210:1100-9. [PMID: 24688070 DOI: 10.1093/infdis/jiu203] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The mechanisms by which α-thalassemia and sickle cell traits confer protection from severe Plasmodium falciparum malaria are not yet fully elucidated. We hypothesized that hemoglobinopathic erythrocytes reduce the intraerythrocytic multiplication of P. falciparum, potentially delaying the development of life-threatening parasite densities until parasite clearing immunity is achieved. METHODS We developed a novel in vitro assay to quantify the number of merozoites released from an individual schizont, termed the "intraerythrocytic multiplication factor" (IMF). RESULTS P. falciparum (3D7 line) schizonts produce variable numbers of merozoites in all erythrocyte types tested, with median IMFs of 27, 27, 29, 23, and 23 in control, HbAS, HbSS, and α- and β-thalassemia trait erythrocytes, respectively. IMF correlated strongly (r(2) = 0.97; P < .001) with mean corpuscular hemoglobin concentration, and varied significantly with mean corpuscular volume and hemoglobin content. Reduction of IMFs in thalassemia trait erythrocytes was confirmed using clinical parasite isolates with different IMFs. Mathematical modeling of the effect of IMF on malaria progression indicates that the lower IMF in thalassemia trait erythrocytes limits parasite density and anemia severity over the first 2 weeks of parasite replication. CONCLUSIONS P. falciparum IMF, a parasite heritable virulence trait, correlates with erythrocyte indices and is reduced in thalassemia trait erythrocytes. Parasite IMF should be examined in other low-indices erythrocytes.
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Affiliation(s)
- Svetlana Glushakova
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health
| | - Amanda Balaban
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health
| | - Philip G McQueen
- Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health
| | - Rosane Coutinho
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health
| | - Jeffery L Miller
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
| | - Ralph Nossal
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Joshua Zimmerberg
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Development, National Institutes of Health
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Beaudry JT, Krause MA, Diakite SAS, Fay MP, Joshi G, Diakite M, White NJ, Fairhurst RM. Ex-vivo cytoadherence phenotypes of Plasmodium falciparum strains from Malian children with hemoglobins A, S, and C. PLoS One 2014; 9:e92185. [PMID: 24647281 PMCID: PMC3960211 DOI: 10.1371/journal.pone.0092185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 02/20/2014] [Indexed: 11/18/2022] Open
Abstract
Sickle hemoglobin (Hb) S and HbC may protect against malaria by reducing the expression of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) on the surface of parasitized red blood cells (RBCs), thereby weakening their cytoadherence to microvascular endothelial cells (MVECs) and impairing their activation of MVECs to produce pathological responses. Therefore, we hypothesized that parasites causing malaria in HbAS or HbAC heterozygotes have overcome this protective mechanism by expressing PfEMP1 variants which mediate relatively strong binding to MVECs. To test this hypothesis, we performed 31 cytoadherence comparisons between parasites from HbAA and HbAS (or HbAC) Malian children with malaria. Ring-stage parasites from HbAA and HbAS (or HbAC) children were cultivated to trophozoites, purified, and then inoculated in parallel into the same wildtype uninfected RBCs. After one cycle of invasion and maturation to the trophozoite stage expressing PfEMP1, parasite strains were compared for binding to MVECs. In this assay, there were no significant differences in the binding of parasites from HbAS and HbAC children to MVECs compared to those from HbAA children (HbAS, fold-change = 1.46, 95% CI 0.97–2.19, p = 0.07; HbAC, fold-change = 1.19, 95% CI 0.77–1.84, p = 0.43). These data suggest that in-vitro reductions in cytoadherence by HbS and HbC may not be selecting for expression of high-avidity PfEMP1 variants in vivo. Future studies that identify PfEMP1 domains or amino-acid motifs which are selectively expressed in parasites from HbAS children may provide further insights into the mechanism of malaria protection by the sickle-cell trait.
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Affiliation(s)
- Jeanette T. Beaudry
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Michael A. Krause
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Seidina A. S. Diakite
- Faculty of Medicine, Pharmacy and Odontostomatology, Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Michael P. Fay
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Gyan Joshi
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mahamadou Diakite
- Faculty of Medicine, Pharmacy and Odontostomatology, Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Nicholas J. White
- Mahidol-Oxford Tropical Diseases Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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van Zwieten R, Verhoeven AJ, Roos D. Inborn defects in the antioxidant systems of human red blood cells. Free Radic Biol Med 2014; 67:377-86. [PMID: 24316370 DOI: 10.1016/j.freeradbiomed.2013.11.022] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 11/20/2013] [Accepted: 11/22/2013] [Indexed: 12/25/2022]
Abstract
Red blood cells (RBCs) contain large amounts of iron and operate in highly oxygenated tissues. As a result, these cells encounter a continuous oxidative stress. Protective mechanisms against oxidation include prevention of formation of reactive oxygen species (ROS), scavenging of various forms of ROS, and repair of oxidized cellular contents. In general, a partial defect in any of these systems can harm RBCs and promote senescence, but is without chronic hemolytic complaints. In this review we summarize the often rare inborn defects that interfere with the various protective mechanisms present in RBCs. NADPH is the main source of reduction equivalents in RBCs, used by most of the protective systems. When NADPH becomes limiting, red cells are prone to being damaged. In many of the severe RBC enzyme deficiencies, a lack of protective enzyme activity is frustrating erythropoiesis or is not restricted to RBCs. Common hereditary RBC disorders, such as thalassemia, sickle-cell trait, and unstable hemoglobins, give rise to increased oxidative stress caused by free heme and iron generated from hemoglobin. The beneficial effect of thalassemia minor, sickle-cell trait, and glucose-6-phosphate dehydrogenase deficiency on survival of malaria infection may well be due to the shared feature of enhanced oxidative stress. This may inhibit parasite growth, enhance uptake of infected RBCs by spleen macrophages, and/or cause less cytoadherence of the infected cells to capillary endothelium.
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Affiliation(s)
- Rob van Zwieten
- Laboratory of Red Blood Cell Diagnostics, Department of Blood Cell Research, Sanquin Blood Supply Organization, 1066 CX Amsterdam, The Netherlands.
| | - Arthur J Verhoeven
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Dirk Roos
- Laboratory of Red Blood Cell Diagnostics, Department of Blood Cell Research, Sanquin Blood Supply Organization, 1066 CX Amsterdam, The Netherlands
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Koldkjær P, McDonald MD, Prior I, Berenbrink M. Pronounced in vivo hemoglobin polymerization in red blood cells of Gulf toadfish: a general role for hemoglobin aggregation in vertebrate hemoparasite defense? Am J Physiol Regul Integr Comp Physiol 2013; 305:R1190-9. [DOI: 10.1152/ajpregu.00246.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two human hemoglobin (Hb) variants, Hb C and Hb S, are known to protect against Plasmodium falciparum malaria and have evolved repeatedly in malaria endemic areas. Both aggregate to insoluble crystals (Hb C) or polymers (Hb S) under certain physiological conditions, impair parasite growth, and may facilitate retention of infected red blood cells (RBCs) in the spleen. Given the profound effects of parasites on host evolution in general, and that RBC Hb concentration is often close to its solubility limit throughout vertebrates, similar mechanisms may operate in nonhuman vertebrates. Here we show exercise-induced, profound in vivo Hb polymerization in RBCs of the Gulf toadfish. Hb aggregation was closely associated with the extent of plasma acidosis, fully reversible, and without any signs of hemolysis or anemia. Our literature analysis suggests that aggregation prone Hbs may be relatively old, evolved multiple times in nonhuman vertebrates, show enhanced aggregation during hemoparasite infections, and can be uncovered in vivo by splenectomy. We discuss the working hypothesis that widespread Hb aggregation within several vertebrate groups may be the result of ongoing or past selection pressure against RBC parasites. Further comparative studies of these evolutionary old systems may provide valuable insights into hemoparasite susceptibility and reservoir potential of livestock and companion animals but also into human malaria and sickle cell disease.
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Affiliation(s)
| | - M. Danielle McDonald
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida
| | - Ian Prior
- Department of Cellular and Molecular Physiology, Institute of Translational Research, University of Liverpool, Liverpool, United Kingdom; and
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Abstract
When the human genome project started, the major challenge was how to sequence a 3 billion letter code in an organized and cost-effective manner. When completed, the project had laid the foundation for a huge variety of biomedical fields through the production of a complete human genome sequence, but also had driven the development of laboratory and analytical methods that could produce large amounts of sequencing data cheaply. These technological developments made possible the sequencing of many more vertebrate genomes, which have been necessary for the interpretation of the human genome. They have also enabled large-scale studies of vertebrate genome evolution, as well as comparative and human medicine. In this review, we give examples of evolutionary analysis using a wide variety of time frames—from the comparison of populations within a species to the comparison of species separated by at least 300 million years. Furthermore, we anticipate discoveries related to evolutionary mechanisms, adaptation, and disease to quickly accelerate in the coming years.
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Affiliation(s)
- Jessica Alföldi
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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Zeituni AE, Miura K, Diakite M, Doumbia S, Moretz SE, Diouf A, Tullo G, Lopera-Mesa TM, Bess CD, Mita-Mendoza NK, Anderson JM, Fairhurst RM, Long CA. Effects of age, hemoglobin type and parasite strain on IgG recognition of Plasmodium falciparum-infected erythrocytes in Malian children. PLoS One 2013; 8:e76734. [PMID: 24124591 PMCID: PMC3790723 DOI: 10.1371/journal.pone.0076734] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 08/28/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Naturally-acquired antibody responses to antigens on the surface of Plasmodium falciparum-infected red blood cells (iRBCs) have been implicated in antimalarial immunity. To profile the development of this immunity, we have been studying a cohort of Malian children living in an area with intense seasonal malaria transmission. METHODOLOGY/PRINCIPAL FINDINGS We collected plasma from a sub-cohort of 176 Malian children aged 3-11 years, before (May) and after (December) the 2009 transmission season. To measure the effect of hemoglobin (Hb) type on antibody responses, we enrolled age-matched HbAA, HbAS and HbAC children. To quantify antibody recognition of iRBCs, we designed a high-throughput flow cytometry assay to rapidly test numerous plasma samples against multiple parasite strains. We evaluated antibody reactivity of each plasma sample to 3 laboratory-adapted parasite lines (FCR3, D10, PC26) and 4 short-term-cultured parasite isolates (2 Malian and 2 Cambodian). 97% of children recognized ≥1 parasite strain and the proportion of IgG responders increased significantly during the transmission season for most parasite strains. Both strain-specific and strain-transcending IgG responses were detected, and varied by age, Hb type and parasite strain. In addition, the breadth of IgG responses to parasite strains increased with age in HbAA, but not in HbAS or HbAC, children. CONCLUSIONS/SIGNIFICANCE Our assay detects both strain-specific and strain-transcending IgG responses to iRBCs. The magnitude and breadth of these responses varied not only by age, but also by Hb type and parasite strain used. These findings indicate that studies of acquired humoral immunity should account for Hb type and test large numbers of diverse parasite strains.
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Affiliation(s)
- Amir E. Zeituni
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Mahamadou Diakite
- Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, Mali
| | - Saibou Doumbia
- Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Bamako, Mali
| | - Samuel E. Moretz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Gregory Tullo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Tatiana M. Lopera-Mesa
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Cameron D. Bess
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Neida K. Mita-Mendoza
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados, México City, México
| | - Jennifer M. Anderson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail:
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Alper SL. Harnessing red cell membrane pathophysiology towards point-of-care diagnosis for sickle cell disease. J Physiol 2013; 591:1403-4. [PMID: 23504232 DOI: 10.1113/jphysiol.2013.252429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Seth L Alper
- Beth Israel Deaconess Medical Center, Divisions of Nephrology and Molecular and Vascular Medicine, 330 Brookline Ave, Boston, MA 02215, USA.
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Affiliation(s)
- Russell E. Ware
- Texas Children's Center for Global Health, Texas Children's Hospital, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Casanova JL, Abel L. The genetic theory of infectious diseases: a brief history and selected illustrations. Annu Rev Genomics Hum Genet 2013; 14:215-43. [PMID: 23724903 PMCID: PMC4980761 DOI: 10.1146/annurev-genom-091212-153448] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Until the mid-nineteenth century, life expectancy at birth averaged 20 years worldwide, owing mostly to childhood fevers. The germ theory of diseases then gradually overcame the belief that diseases were intrinsic. However, around the turn of the twentieth century, asymptomatic infection was discovered to be much more common than clinical disease. Paradoxically, this observation barely challenged the newly developed notion that infectious diseases were fundamentally extrinsic. Moreover, interindividual variability in the course of infection was typically explained by the emerging immunological (or somatic) theory of infectious diseases, best illustrated by the impact of vaccination. This powerful explanation is, however, best applicable to reactivation and secondary infections, particularly in adults; it can less easily account for interindividual variability in the course of primary infection during childhood. Population and clinical geneticists soon proposed a complementary hypothesis, a germline genetic theory of infectious diseases. Over the past century, this idea has gained some support, particularly among clinicians and geneticists, but has also encountered resistance, particularly among microbiologists and immunologists. We present here the genetic theory of infectious diseases and briefly discuss its history and the challenges encountered during its emergence in the context of the apparently competing but actually complementary microbiological and immunological theories. We also illustrate its recent achievements by highlighting inborn errors of immunity underlying eight life-threatening infectious diseases of children and young adults. Finally, we consider the far-reaching biological and clinical implications of the ongoing human genetic dissection of severe infectious diseases.
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Affiliation(s)
- Jean-Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY 10065;
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Abstract
Iron is a redox active metal which is abundant in the Earth's crust. It has played a key role in the evolution of living systems and as such is an essential element in a wide range of biological phenomena, being critical for the function of an enormous array of enzymes, energy transduction mechanisms, and oxygen carriers. The redox nature of iron renders the metal toxic in excess and consequently all biological organisms carefully control iron levels. In this overview the mechanisms adopted by man to control body iron levels are described.Low body iron levels are related to anemia which can be treated by various forms of iron fortification and supplementation. Elevated iron levels can occur systemically or locally, each giving rise to specific symptoms. Systemic iron overload results from either the hyperabsorption of iron or regular blood transfusion and can be treated by the use of a selection of iron chelating molecules. The symptoms of many forms of neurodegeneration are associated with elevated levels of iron in certain regions of the brain and iron chelation therapy is beginning to find an application in the treatment of such diseases. Iron chelators have also been widely investigated for the treatment of cancer, tuberculosis, and malaria. In these latter studies, selective removal of iron from key enzymes or iron binding proteins is sought. Sufficient selectivity between the invading organism and the host has yet to be established for such chelators to find application in the clinic.Iron chelation for systemic iron overload and iron supplementation therapy for the treatment of various forms of anemia are now established procedures in clinical medicine. Chelation therapy may find an important role in the treatment of various neurodegenerative diseases in the near future.
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