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Kho S, Qotrunnada L, Leonardo L, Andries B, Wardani PAI, Fricot A, Henry B, Hardy D, Margyaningsih NI, Apriyanti D, Puspitasari AM, Prayoga P, Trianty L, Kenangalem E, Chretien F, Brousse V, Safeukui I, del Portillo HA, Fernandez-Becerra C, Meibalan E, Marti M, Price RN, Woodberry T, Ndour PA, Russell BM, Yeo TW, Minigo G, Noviyanti R, Poespoprodjo JR, Siregar NC, Buffet PA, Anstey NM. Evaluation of splenic accumulation and colocalization of immature reticulocytes and Plasmodium vivax in asymptomatic malaria: A prospective human splenectomy study. PLoS Med 2021; 18:e1003632. [PMID: 34038413 PMCID: PMC8154101 DOI: 10.1371/journal.pmed.1003632] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 04/19/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND A very large biomass of intact asexual-stage malaria parasites accumulates in the spleen of asymptomatic human individuals infected with Plasmodium vivax. The mechanisms underlying this intense tropism are not clear. We hypothesised that immature reticulocytes, in which P. vivax develops, may display high densities in the spleen, thereby providing a niche for parasite survival. METHODS AND FINDINGS We examined spleen tissue in 22 mostly untreated individuals naturally exposed to P. vivax and Plasmodium falciparum undergoing splenectomy for any clinical indication in malaria-endemic Papua, Indonesia (2015 to 2017). Infection, parasite and immature reticulocyte density, and splenic distribution were analysed by optical microscopy, flow cytometry, and molecular assays. Nine non-endemic control spleens from individuals undergoing spleno-pancreatectomy in France (2017 to 2020) were also examined for reticulocyte densities. There were no exclusion criteria or sample size considerations in both patient cohorts for this demanding approach. In Indonesia, 95.5% (21/22) of splenectomy patients had asymptomatic splenic Plasmodium infection (7 P. vivax, 13 P. falciparum, and 1 mixed infection). Significant splenic accumulation of immature CD71 intermediate- and high-expressing reticulocytes was seen, with concentrations 11 times greater than in peripheral blood. Accordingly, in France, reticulocyte concentrations in the splenic effluent were higher than in peripheral blood. Greater rigidity of reticulocytes in splenic than in peripheral blood, and their higher densities in splenic cords both suggest a mechanical retention process. Asexual-stage P. vivax-infected erythrocytes of all developmental stages accumulated in the spleen, with non-phagocytosed parasite densities 3,590 times (IQR: 2,600 to 4,130) higher than in circulating blood, and median total splenic parasite loads 81 (IQR: 14 to 205) times greater, accounting for 98.7% (IQR: 95.1% to 98.9%) of the estimated total-body P. vivax biomass. More reticulocytes were in contact with sinus lumen endothelial cells in P. vivax- than in P. falciparum-infected spleens. Histological analyses revealed 96% of P. vivax rings/trophozoites and 46% of schizonts colocalised with 92% of immature reticulocytes in the cords and sinus lumens of the red pulp. Larger splenic cohort studies and similar investigations in untreated symptomatic malaria are warranted. CONCLUSIONS Immature CD71+ reticulocytes and splenic P. vivax-infected erythrocytes of all asexual stages accumulate in the same splenic compartments, suggesting the existence of a cryptic endosplenic lifecycle in chronic P. vivax infection. Findings provide insight into P. vivax-specific adaptions that have evolved to maximise survival and replication in the spleen.
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Affiliation(s)
- Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | | | - Leo Leonardo
- Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Benediktus Andries
- Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | | | - Aurelie Fricot
- UMR_S1134, BIGR, Inserm, Université de F-75015 Paris, and Laboratory of Excellence GR-Ex, Paris, France
| | - Benoit Henry
- UMR_S1134, BIGR, Inserm, Université de F-75015 Paris, and Laboratory of Excellence GR-Ex, Paris, France
| | - David Hardy
- Institut Pasteur, Experimental Neuropathology Unit, Paris, France
| | | | - Dwi Apriyanti
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | | | - Pak Prayoga
- Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Leily Trianty
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Enny Kenangalem
- Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
- Rumah Sakit Umum Daerah Kabupaten Mimika, Timika, Papua, Indonesia
| | - Fabrice Chretien
- Institut Pasteur, Experimental Neuropathology Unit, Paris, France
| | - Valentine Brousse
- UMR_S1134, BIGR, Inserm, Université de F-75015 Paris, and Laboratory of Excellence GR-Ex, Paris, France
| | - Innocent Safeukui
- Department of Biological Sciences, Notre Dame University, Notre Dame, Indiana, United States of America
| | - Hernando A. del Portillo
- ISGlobal, Hospital Clinic-Universitat de Barcelona, Barcelona, Spain
- Germans Trias I Pujol Research Institute, Badalona, Spain
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Carmen Fernandez-Becerra
- ISGlobal, Hospital Clinic-Universitat de Barcelona, Barcelona, Spain
- Germans Trias I Pujol Research Institute, Badalona, Spain
| | - Elamaran Meibalan
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Wellcome Center for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Center for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tonia Woodberry
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Papa A. Ndour
- UMR_S1134, BIGR, Inserm, Université de F-75015 Paris, and Laboratory of Excellence GR-Ex, Paris, France
| | - Bruce M. Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Tsin W. Yeo
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Gabriela Minigo
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | | | - Jeanne R. Poespoprodjo
- Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
- Rumah Sakit Umum Daerah Kabupaten Mimika, Timika, Papua, Indonesia
- Department of Pediatrics, University of Gadjah Mada, Yogyakarta, Indonesia
| | - Nurjati C. Siregar
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
- Department of Anatomical Pathology, Rumah Sakit Cipto Mangunkusumo and Universitas Indonesia, Jakarta, Indonesia
| | - Pierre A. Buffet
- UMR_S1134, BIGR, Inserm, Université de F-75015 Paris, and Laboratory of Excellence GR-Ex, Paris, France
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
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