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Egan ES, Jiang RHY, Moechtar MA, Barteneva NS, Weekes MP, Nobre LV, Gygi SP, Paulo JA, Frantzreb C, Tani Y, Takahashi J, Watanabe S, Goldberg J, Paul AS, Brugnara C, Root DE, Wiegand RC, Doench JG, Duraisingh MT. Malaria. A forward genetic screen identifies erythrocyte CD55 as essential for Plasmodium falciparum invasion. Science 2015; 348:711-4. [PMID: 25954012 DOI: 10.1126/science.aaa3526] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Efforts to identify host determinants for malaria have been hindered by the absence of a nucleus in erythrocytes, which precludes genetic manipulation in the cell in which the parasite replicates. We used cultured red blood cells derived from hematopoietic stem cells to carry out a forward genetic screen for Plasmodium falciparum host determinants. We found that CD55 is an essential host factor for P. falciparum invasion. CD55-null erythrocytes were refractory to invasion by all isolates of P. falciparum because parasites failed to attach properly to the erythrocyte surface. Thus, CD55 is an attractive target for the development of malaria therapeutics. Hematopoietic stem cell-based forward genetic screens may be valuable for the identification of additional host determinants of malaria pathogenesis.
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Affiliation(s)
- Elizabeth S Egan
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA. Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, USA
| | - Rays H Y Jiang
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA. Department of Global Health and Center for Drug Discovery and Innovation, University of South Florida, Tampa, FL, USA
| | - Mischka A Moechtar
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Natasha S Barteneva
- Department of Pediatrics, Harvard Medical School and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Michael P Weekes
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Luis V Nobre
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Charles Frantzreb
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Yoshihiko Tani
- Japanese Red Cross Kinki Block Blood Center, Osaka, Japan
| | | | - Seishi Watanabe
- Japanese Red Cross Kyushu Block Blood Center, Fukuoka, Japan
| | - Jonathan Goldberg
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Aditya S Paul
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - David E Root
- The Broad Institute of Harvard and Massachussetts Insititute of Technology, Cambridge, MA, USAA
| | - Roger C Wiegand
- The Broad Institute of Harvard and Massachussetts Insititute of Technology, Cambridge, MA, USAA
| | - John G Doench
- The Broad Institute of Harvard and Massachussetts Insititute of Technology, Cambridge, MA, USAA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA. The Broad Institute of Harvard and Massachussetts Insititute of Technology, Cambridge, MA, USAA.
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Abstract
Sickle cell disease (SCD) is a genetic disorder that poses a serious health threat in tropical Africa, which the World Health Organization has declared a public health priority. Its persistence in human populations has been attributed to the resistance it provides to Plasmodium falciparum malaria in its heterozygous state, called sickle cell trait (SCT). Because of migration, SCT is becoming common outside tropical countries: It is now the most important genetic disorder in France, affecting one birth for every 2,400, and one of the most common in the United States. We assess the strength of the association between SCT and malaria, using current data for both SCT and malaria infections. A total of 3,959 blood samples from 195 villages distributed over the entire Republic of Gabon were analyzed. Hemoglobin variants were identified by using HPLCy (HPLC). Infections by three species of Plasmodium were detected by PCR followed by sequencing of a 201-bp fragment of cytochrome b. An increase of 10% in P. falciparum malaria prevalence is associated with an increase by 4.3% of SCT carriers. An increase of 10 y of age is associated with an increase by 5.5% of SCT carriers. Sex is not associated with SCT. These strong associations show that malaria remains a selective factor in current human populations, despite the progress of medicine and the actions undertaken to fight this disease. Our results provide evidence that evolution is still present in humans, although this is sometimes questioned by scientific, political, or religious personalities.
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153
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Lopera-Mesa TM, Doumbia S, Konaté D, Anderson JM, Doumbouya M, Keita AS, Diakité SAS, Traoré K, Krause MA, Diouf A, Moretz SE, Tullo GS, Miura K, Gu W, Fay MP, Taylor SM, Long CA, Diakité M, Fairhurst RM. Effect of red blood cell variants on childhood malaria in Mali: a prospective cohort study. Lancet Haematol 2015; 2:e140-9. [PMID: 26687956 PMCID: PMC4418020 DOI: 10.1016/s2352-3026(15)00043-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 02/27/2015] [Accepted: 02/27/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Red blood cell variants protect African children from severe falciparum malaria. However, their individual and interactive effects on mild disease and parasite density, and their modification by age-dependent immunity, are poorly understood. In this study, we address these knowledge gaps in a prospective cohort study of malaria risk and Plasmodium falciparum densities in Malian children. METHODS The Kenieroba Innate Defense Study for Malaria (KIDS-Malaria) was a 4-year prospective cohort study of children aged 6 months to 17 years undertaken in Mali between 2008 and 2011. Red blood cell variants were haemoglobin S (HbS), haemoglobin C (HbC), α thalassaemia, ABO blood groups, and glucose-6-phosphate dehydrogenase (G6PD) deficiency encoded by the X-linked A- allele. The primary outcome was malaria incidence, measured as the number of uncomplicated or severe malaria episodes over time. The secondary outcome was parasite density at the time of a malaria episode. We modelled incidence rate ratios with quasi-Poisson regression and we analysed parasite densities using generalised estimating equations. This study is registered with ClinicalTrials.gov, number NCT00669084. FINDINGS Between May 1, 2008, and Dec 29, 2011, we enrolled 1586 children into the study. We successfully typed all five red blood cell variants for 1543 of these children, who therefore constituted the evaluable population and in whom we diagnosed 4091 malaria episodes over 2656 child-years of follow-up. In these 1543 children, red blood cell variants were common, and occurred at the following frequencies: sickle cell trait (HbAS) 220 (14%), HbC heterozygosity (HbAC) 103 (7%), α thalassaemia 438 (28%), type O blood group 621 (40%), and G6PD deficiency 72 (9%) in 767 boys and 158 (20%) in 776 girls. The overall incidence of malaria was 1.54 episodes per child-year of follow-up, ranging from 2.78 episodes per child-year at age 3 years to 0.40 episodes per child-year at age 17 years. The malaria incidence was lower in HbAS children than in HbAA children with normal haemoglobin (adjusted incidence rate ratio [aIRR] 0.66 [95% CI 0.59-0.75], p<0.0001) and lower in G6PD A-/A- homozygous girls than in G6PD A+/A+ girls (0.51 [0.29-0.90], p=0.020), but was higher in HbAC children than in HbAA children (1.15 [1.01-1.32], p=0.039). Parasite density was lower in HbAS children (median 10,550 parasites per μL [IQR 1350-26,250]) than in HbAA children (15,150 parasites per μL [4250-31,050]; p=0.0004). The HbAS-associated reductions in malaria risk and parasite density were greatest in early childhood. INTERPRETATION The individual and interactive effects of HbAS, HbAC, and G6PD A-/A- genotypes on malaria risk and parasite density define clinical and cellular correlates of protection. Further identification of the molecular mechanisms of these protective effects might uncover new targets for intervention. FUNDING Intramural Research Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health.
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Affiliation(s)
- Tatiana M Lopera-Mesa
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Saibou Doumbia
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Jennifer M Anderson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mory Doumbouya
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Abdoul S Keita
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | | | - Karim Traoré
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Michael A Krause
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Samuel E Moretz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Gregory S Tullo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; Kelly Scientific Resources, Rockville, MD, USA
| | - Wenjuan Gu
- Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Michael P Fay
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Steve M Taylor
- Division of Infectious Diseases and International Health and Duke Global Health Institute, Duke University Medical Center, Durham, NC, USA; Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mahamadou Diakité
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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154
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Williams TN. Red blood cell variants and malaria: a long story not yet over. LANCET HAEMATOLOGY 2015; 2:e130-1. [PMID: 26687952 DOI: 10.1016/s2352-3026(15)00049-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 11/26/2022]
Affiliation(s)
- Thomas Neil Williams
- Department of Medicine, Imperial College London, St Mary's Hospital, Praed Street, London, W2 1NY, UK.
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155
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Mangano VD, Kabore Y, Bougouma EC, Verra F, Sepulveda N, Bisseye C, Santolamazza F, Avellino P, Tiono AB, Diarra A, Nebie I, Rockett KA, Sirima SB, Modiano D. Novel Insights Into the Protective Role of Hemoglobin S and C Against Plasmodium falciparum Parasitemia. J Infect Dis 2015; 212:626-34. [PMID: 25712976 PMCID: PMC4512610 DOI: 10.1093/infdis/jiv098] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/13/2015] [Indexed: 02/04/2023] Open
Abstract
Although hemoglobin S (HbS) and hemoglobin C (HbC) are well known to protect against severe Plasmodium falciparum malaria, conclusive evidence on their role against infection has not yet been obtained. Here we show, in 2 populations from Burkina Faso (2007-2008), that HbS is associated with a 70% reduction of harboring P. falciparum parasitemia at the heterozygous state (odds ratio [OR] for AS vs AA, 0.27; 95% confidence interval [CI], .11-.66; P = .004). There is no evidence of protection for HbC in the heterozygous state (OR for AC vs AA, 1.49; 95% CI, .69-3.21; P = .31), whereas protection even higher than that observed with AS is observed in the homozygous and double heterozygous states (OR for CC + SC vs AA, 0.04; 95% CI, .01-.29; P = .002). The abnormal display of parasite-adhesive molecules on the surface of HbS and HbC infected erythrocytes, disrupting the pathogenic process of sequestration, might displace the parasite from the deep to the peripheral circulation, promoting its elimination at the spleen level.
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Affiliation(s)
- Valentina D Mangano
- Department of Public Health and Infectious Diseases Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
| | - Youssouf Kabore
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Edith C Bougouma
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Nuno Sepulveda
- London School of Hygiene and Tropical Medicine Center of Statistics and Applications of University of Lisbon, Portugal
| | - Cyrille Bisseye
- Department of Public Health and Infectious Diseases Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | | | - Alfred B Tiono
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Amidou Diarra
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nebie
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Kirk A Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Sodiomon B Sirima
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - David Modiano
- Department of Public Health and Infectious Diseases Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
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156
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Dewasurendra RL, Rockett KA, Fernando SD, Carter R, Kwiatkowski DP, Karunaweera ND. G6PD gene variants and its association with malaria in a Sri Lankan population. Malar J 2015; 14:93. [PMID: 25885177 PMCID: PMC4343272 DOI: 10.1186/s12936-015-0603-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme that plays an important role in many cellular functions. Deficiency of this enzyme results from point mutations in the coding region of the G6PD gene. G6PD-deficiency is important in malaria, as certain anti-malarial drugs could induce haemolysis in such patients and mutations in this gene may influence the susceptibility or resistance to the disease. Detailed information on genetic variations in the G6PD gene for Sri Lankan populations is yet to be revealed. This study describes a set of G6PD mutations present in a Sri Lankan population and their association with uncomplicated malaria. METHODS DNA was extracted from 1,051 individuals. Sixty-eight SNPs in the region of the G6PD gene were genotyped. A database created during the 1992-1993 malaria epidemic for the same individuals was used to assess the associations between the G6PD SNPs and parasite density or disease severity of uncomplicated malaria infections. Linkage disequilibrium for SNPs and haplotype structures were identified. RESULTS Seventeen genetic variants were polymorphic in this population. The mutant allele was the major allele in 9 SNPs. Common G6PD variants already described in Asians or South-Asians seemed to be absent or rare in this population. Both the severity of disease in uncomplicated malaria infections and parasitaemia were significantly lower in males infected with Plasmodium falciparum carrying the ancestral allele of rs915942 compared to those carrying the mutant allele. The parasite density of males infected with P. falciparum was significantly lower also in those who possessed the mutant alleles of rs5986877, rs7879049 and rs7053878. Two haplotype blocks were identified, where the recombination rates were higher in males with no history of malaria when compared to those who have experienced the disease in the past. CONCLUSIONS This is the most detailed survey of G6PD SNPs in a Sri Lankan population undertaken so far that enabled novel description of single nucleotide polymorphisms within the G6PD gene. A few of these genetic variations identified, demonstrated a tendency to be associated with either disease severity or parasite density in uncomplicated disease in males. Known G6PD gene polymorphisms already described from elsewhere were either absent or rare in the local study population.
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Affiliation(s)
- Rajika L Dewasurendra
- Department of Parasitology, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo 08, Sri Lanka.
| | - Kirk A Rockett
- TheWellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3, 7BN, UK.
| | - S Deepika Fernando
- Department of Parasitology, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo 08, Sri Lanka.
| | - Richard Carter
- Division of Biological Sciences, Ashworth Laboratories, University of Edinburgh, West Mains Rd, Edinburgh, EH9 3JT, UK.
| | - Dominic P Kwiatkowski
- TheWellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3, 7BN, UK. .,Wellcome Trust Sanger Institute, Cambridge, UK.
| | - Nadira D Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo 08, Sri Lanka.
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157
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Manjurano A, Sepulveda N, Nadjm B, Mtove G, Wangai H, Maxwell C, Olomi R, Reyburn H, Riley EM, Drakeley CJ, Clark TG. African glucose-6-phosphate dehydrogenase alleles associated with protection from severe malaria in heterozygous females in Tanzania. PLoS Genet 2015; 11:e1004960. [PMID: 25671784 PMCID: PMC4335500 DOI: 10.1371/journal.pgen.1004960] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/17/2014] [Indexed: 11/24/2022] Open
Abstract
X-linked Glucose-6-phosphate dehydrogenase (G6PD) A- deficiency is prevalent in sub-Saharan Africa populations, and has been associated with protection from severe malaria. Whether females and/or males are protected by G6PD deficiency is uncertain, due in part to G6PD and malaria phenotypic complexity and misclassification. Almost all large association studies have genotyped a limited number of G6PD SNPs (e.g. G6PD202 / G6PD376), and this approach has been too blunt to capture the complete epidemiological picture. Here we have identified 68 G6PD polymorphisms and analysed 29 of these (i.e. those with a minor allele frequency greater than 1%) in 983 severe malaria cases and controls in Tanzania. We establish, across a number of SNPs including G6PD376, that only female heterozygotes are protected from severe malaria. Haplotype analysis reveals the G6PD locus to be under balancing selection, suggesting a mechanism of protection relying on alleles at modest frequency and avoiding fixation, where protection provided by G6PD deficiency against severe malaria is offset by increased risk of life-threatening complications. Our study also demonstrates that the much-needed large-scale studies of severe malaria and G6PD enzymatic function across African populations require the identification and analysis of the full repertoire of G6PD genetic markers. Glucose-6-phosphate dehydrogenase (G6PD) is an essential enzyme that protects red blood cells from oxidative damage. Numerous genetic variants of G6PD, residing in the X chromosome, are found among African populations: mutations causing A- deficiency can lead to serious clinical outcomes (including hemolytic anemia) but also confer protection against severe malaria. Epidemiological studies have used some of the genetic markers that cause A- deficiency to establish who is protected from severe malaria, with differing results. Whether females, with one or two copies of mutant genes, males with one copy, or both genders are protected is uncertain. This uncertainty is due to G6PD and malaria phenotypic complexity and misclassification, and to genetic differences between populations and the limited numbers of genetic markers (usually 2) considered. In this study we analysed more than 30 G6PD genetic markers in 506 Tanzanian children with severe malaria and 477 without malaria. We found that only females with one normal and one mutant copy of the gene (heterozygotes) were protected from severe malaria. Further, we established that the G6PD gene is under evolutionary pressure with the likely mechanism being selection by malaria. Our work demonstrates that studies of severe malaria and G6PD enzymatic function across African populations require, in addition to complete and accurate G6PD phenotypic classification, the identification and analysis of the full repertoire of G6PD genetic markers.
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Affiliation(s)
- Alphaxard Manjurano
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Nuno Sepulveda
- Department of Infection and Immunology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Behzad Nadjm
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - George Mtove
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Hannah Wangai
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Caroline Maxwell
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Raimos Olomi
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Hugh Reyburn
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
- Department of Infection and Immunology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eleanor M. Riley
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
- Department of Infection and Immunology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher J. Drakeley
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
- Department of Infection and Immunology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Taane G. Clark
- Pathogen Molecular Biology Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - MalariaGEN Consortium
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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158
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Differential positive selection of malaria resistance genes in three indigenous populations of Peninsular Malaysia. Hum Genet 2015; 134:375-92. [PMID: 25634076 DOI: 10.1007/s00439-014-1525-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 12/25/2014] [Indexed: 10/24/2022]
Abstract
The indigenous populations from Peninsular Malaysia, locally known as Orang Asli, continue to adopt an agro-subsistence nomadic lifestyle, residing primarily within natural jungle habitats. Leading a hunter-gatherer lifestyle in a tropical jungle environment, the Orang Asli are routinely exposed to malaria. Here we surveyed the genetic architecture of individuals from four Orang Asli tribes with high-density genotyping across more than 2.5 million polymorphisms. These tribes reside in different geographical locations in Peninsular Malaysia and belong to three main ethno-linguistic groups, where there is minimal interaction between the tribes. We first dissect the genetic diversity and admixture between the tribes and with neighboring urban populations. Later, by implementing five metrics, we investigated the genome-wide signatures for positive natural selection of these Orang Asli, respectively. Finally, we searched for evidence of genomic adaptation to the pressure of malaria infection. We observed that different evolutionary responses might have emerged in the different Orang Asli communities to mitigate malaria infection.
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159
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Abstract
Parasites still impose a high death and disability burden on human populations, and are therefore likely to act as selective factors for genetic adaptations. Genetic epidemiological investigation of parasitic diseases is aimed at disentangling the mechanisms underlying immunity and pathogenesis by looking for associations or linkages between loci and susceptibility phenotypes. Until recently, most studies used a candidate gene approach and were relatively underpowered, with few attempts at replicating findings in different populations. However, in the last 5 years, genome-wide and/or multicentre studies have been conducted for severe malaria, visceral leishmaniasis, and cardiac Chagas disease, providing some novel important insights. Furthermore, studies of helminth infections have repeatedly shown the involvement of common loci in regulating susceptibility to distinct diseases such as schistosomiasis, ascariasis, trichuriasis, and onchocherciasis. As more studies are conducted, evidence is increasing that at least some of the identified susceptibility loci are shared not only among parasitic diseases but also with immunological disorders such as allergy or autoimmune disease, suggesting that parasites may have played a role in driving the evolution of the immune system.
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Affiliation(s)
- V D Mangano
- Department of Public Health and Infectious Diseases, University of Rome 'La Sapienza', Rome, Italy; Istituto Pasteur, Fondazione Cenci Bolognetti, University of Rome 'La Sapienza', Rome, Italy
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160
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Geller G, Dvoskin R, Thio CL, Duggal P, Lewis MH, Bailey TC, Sutherland A, Salmon DA, Kahn JP. Genomics and infectious disease: a call to identify the ethical, legal and social implications for public health and clinical practice. Genome Med 2014; 6:106. [PMID: 25593592 PMCID: PMC4295297 DOI: 10.1186/s13073-014-0106-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Advances in genomics are contributing to the development of more effective, personalized approaches to the prevention and treatment of infectious diseases. Genetic sequencing technologies are furthering our understanding of how human and pathogen genomic factors - and their interactions - contribute to individual differences in immunologic responses to vaccines, infections and drug therapies. Such understanding will influence future policies and procedures for infectious disease management. With the potential for tailored interventions for particular individuals, populations or subpopulations, ethical, legal and social implications (ELSIs) may arise for public health and clinical practice. Potential considerations include balancing health-related benefits and harms between individuals and the larger community, minimizing threats to individual privacy and autonomy, and ensuring just distribution of scarce resources. In this Opinion, we consider the potential application of pathogen and host genomic information to particular viral infections that have large-scale public health consequences but differ in ELSI-relevant characteristics such as ease of transmission, chronicity, severity, preventability and treatability. We argue for the importance of anticipating these ELSI issues in advance of new scientific discoveries, and call for the development of strategies for identifying and exploring ethical questions that should be considered as clinical, public health and policy decisions are made.
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Affiliation(s)
- Gail Geller
- Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205 USA ; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA ; Department of Health, Behavior & Society, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA ; Department of Health Policy and Management, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Rachel Dvoskin
- Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205 USA
| | - Chloe L Thio
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Priya Duggal
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Michelle H Lewis
- Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205 USA
| | - Theodore C Bailey
- Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205 USA ; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Andrea Sutherland
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Daniel A Salmon
- Department of Health, Behavior & Society, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA ; Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
| | - Jeffrey P Kahn
- Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD 21205 USA ; Department of Health Policy and Management, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA
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Kerasidou A. Sharing the Knowledge: Sharing Aggregate Genomic Findings with Research Participants in Developing Countries. Dev World Bioeth 2014; 15:267-74. [PMID: 25292263 PMCID: PMC4632193 DOI: 10.1111/dewb.12071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Returning research results to participants is recognised as an obligation that researchers should always try to fulfil. But can we ascribe the same obligation to researchers who conduct genomics research producing only aggregated findings? And what about genomics research conducted in developing countries? This paper considers Beskow’s et al. argument that aggregated findings should also be returned to research participants. This recommendation is examined in the context of genomics research conducted in developing countries. The risks and benefits of attempting such an exercise are identified, and suggestions on ways to avoid some of the challenges are proposed. I argue that disseminating the findings of genomic research to participating communities should be seen as sharing knowledge rather than returning results. Calling the dissemination of aggregate, population level information returning results can be confusing and misleading as participants might expect to receive individual level information. Talking about sharing knowledge is a more appropriate way of expressing and communicating the outcome of population genomic research. Considering the knowledge produced by genomics research a worthwhile output that should be shared with the participants and approaching the exercise as a ‘sharing of knowledge’, could help mitigate the risks of unrealistic expectations and misunderstanding of findings, whilst promoting trusting and long lasting relationships with the participating communities.
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