Total parasite biomass but not peripheral parasitaemia is associated with endothelial and haematological perturbations in Plasmodium vivax patients
- University of Glasgow, United Kingdom
- Laboratory of Tropical Diseases, University of Campinas, Brazil
- Institute of Biology, University of Campinas, Brazil
- Institute of Infection Immunity and Inflammation, University of Glasgow, United Kingdom
- 3School of Pharmaceutical Sciences, University of São Paulo, Brazil
- University of São Paulo, Brazil
- University of Campinas, Brazil
- Institute Leônidas and Maria Deane, Brazil
- Tropical Medicine Foundation, Brazil
Abstract
Plasmodium vivax is the major cause of human malaria in the Americas. How P. vivax infection can lead to poor clinical outcomes, despite low peripheral parasitaemia remains a matter of intense debate. Estimation of total P. vivax biomass based on circulating markers indicates existence of a predominant parasite population outside of circulation. In this study we investigate associations between both peripheral and total parasite biomass and host response in vivax malaria. We analysed parasite and host signatures in a cohort of uncomplicated vivax malaria patients from Manaus, Brazil, combining clinical and parasite parameters, multiplexed analysis of host responses and ex vivo assays. Patterns of clinical features, parasite burden and host signatures measured in plasma across the patient cohort were highly heterogenous. Further data deconvolution revealed two patient clusters, here termed Vivaxlow and Vivaxhigh. These patient subgroups were defined based on differences in total parasite biomass but not peripheral parasitaemia. Overall Vivaxlow patients clustered with healthy donors and Vivaxhigh patients showed more profound alterations in haematological parameters, endothelial cell (EC) activation and glycocalyx breakdown and levels of cytokines regulating different haematopoiesis pathways compared to Vivaxlow. Vivaxhigh patients presented more severe thrombocytopenia and lymphopenia, along with enrichment of neutrophils in the peripheral blood and increased neutrophil-to-lymphocyte ratio (NLCR). When patients' signatures were combined, high association of total parasite biomass with a subset of markers of EC activation, thrombocytopenia and lymphopenia severity was observed. Finally, machine learning models defined a combination of host parameters measured in the circulation that could predict the extent of parasite infection outside of circulation. Altogether, our data show that total parasite biomass is a better predictor of perturbations in host homeostasis in P. vivax patients than peripheral parasitaemia. This supports the emerging paradigm of a P. vivax tissue reservoir, in particular in the hematopoietic niche of bone marrow and spleen.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Numerical tables and source data files have been provided. Table 1, Figure 2-source data 1 and Figure 2-figure supplement 2-source data 1 contain the numerical data used to generate the figures.
Article and author information
Author details
João Luiz Silva-Filho
João CK Dos-Santos
Funding
Fundação de Amparo à Pesquisa do Estado de São Paulo (2019/01578-2)
- João Luiz Silva-Filho
Fundação de Amparo à Pesquisa do Estado de São Paulo (2017/18611-7)
- João Luiz Silva-Filho
Wellcome Trust (104111)
- João Luiz Silva-Filho
Fundação de Amparo à Pesquisa do Estado de São Paulo (2016/12855-9)
- João Luiz Silva-Filho
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: All subjects enrolled in the study were adults. Written informed consent was obtained from all participants and the study was conducted according to the Declaration of Helsinki principles. The study was approved by the local Research Ethics Committee at Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD, Manaus, Brazil), under #CAAE: 54234216.1.0000.0005.
Copyright
© 2021, Silva-Filho et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Total parasite biomass but not peripheral parasitaemia is associated with endothelial and haematological perturbations in Plasmodium vivax patients
eLife 10:e71351.
https://doi.org/10.7554/eLife.71351
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