Anemia and innate immune response profile in Plasmodium vivax co-infection in an endemic area of the Brazilian Amazon

In Brazil, malaria is concentrated almost entirely in the north of the country, where there is diversity in transmission dynamics. Anemia is one of the main clinical features in malaria and its origin has been described as multifactorial. In addition, Plasmodium vivax is the main species responsible for malaria in Brazil and studies characterizing its anemia profile are scarce.

Cross-sectional analytical study carried out with clinical samples that were collected from individuals residing in the municipality of Oiapoque, Amapá, border area between Brazil and French Guiana from November 2014 to November 2015, in which the diagnosis of malaria was confirmed by methods parasitological and molecular. The survey comprised four distinct groups grouped into: (M) Monoinfected with malaria by P. vivax; (CI) Co-infected P. vivax malaria and enteroparasites; (E) monoinfected with enteroparasites and (C) control (negative for both diseases). A total of 441 individuals were included, grouped according to their infection status: [M 6.9% (30/441)], [CI 26.5% (117/441)], [E 32.4% (143/441) )] and [EC 34.2% (151/441)]. The B19V genotype circulating in the region will be determined, the B19V-DNA positive samples will be submitted to the Semi-Nested PCR reaction. TREM-1 and Toll-like gene polymorphisms will be analyzed by PCR. Cytokine levels (Th1: IL-2, INFγ and TNF) and (Th2: IL-4, IL-5, IL-10) will be evaluated by flow cytometry and the dosage of anti-TREM-1 antibodies in serum will be quantified by ELISA. The analysis of the existence of correlation between cytokine levels and parasite density, as well as the correlation between the study groups will be estimated by Spearman and Kruskal-Wallis non-parametric correlation test followed by Dunn’s post-test, using the Graph-pad prism 6.0 program. For the analysis of polymorphisms, the allele and genotypic frequencies will be compared between the study groups and the significance of the deviations will be verified using the G-test and Pearson’s chi-square test, respectively, using the Bioestat® version 5.0 program. Furthermore, statistical tests will be used to assess significant associations between B19V/malaria co-infection, age, sex, anemia, parasitemia and the presence of enteroparasites. The results obtained may contribute to the identification and evaluation of factors related to the host, especially in the modulation of the innate and humoral immune response, allowing speculation about the risk or protection of the development of anemia, opening possibilities for obtaining new forms of malaria treatment and prevention of its complications.

Project details

Basic Science
P. vivax

Jan 2019

Brazil