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BACKGROUND: In malaria infection, apoptosis acts as an important immunomodulatory mechanism that leads to the elimination of parasitized cells, thus reducing the parasite density and controlling immune cell populations. Here, it was investigated the association of INDEL variants in apoptotic genes-rs10562972 (FAS), rs4197 (FADD), rs3834129 and rs59308963 (CASP8), rs61079693 (CASP9), rs4647655 (CASP3), rs11269260 (BCL-2), and rs17880560 (TP53)-and the influence of genetic ancestry with susceptibility to malaria and parasite density in an admixed population from the Brazilian Amazon. METHODS: Total DNA was extracted from 126 malaria patients and 101 uninfected individuals for investigation of genetic ancestries and genotypic distribution of apoptosis-related variants by Multiplex PCR. Association analyses consisted of multivariate logistic regressions, considering the following comparisons: (i) DEL/DEL genotype vs. INS/DEL + INS/INS; and (ii) INS/INS vs. INS/DEL + DEL/DEL. RESULTS: Individuals infected by Plasmodium falciparum had significantly higher African ancestry proportions in comparison to uninfected controls, Plasmodium vivax, and mixed infections. The INS/INS genotype of rs3834129 (CASP8) seemed to increase the risk for P. falciparum infection (P = 0.038; OR = 1.867; 95% CI 0.736-3.725), while the DEL/DEL genotype presented a significant protective effect against infection by P. falciparum (P = 0.049; OR = 0.446; 95% CI 0.185-0.944) and mixed infection (P = 0.026; OR = 0.545; 95% CI 0.281-0.996), and was associated with lower parasite density in P. falciparum malaria (P = 0.009; OR = 0.383; 95% CI 0.113-1.295). Additionally, the INS/INS genotype of rs10562972 (FAS) was more frequent among individuals infected with P. vivax compared to P. falciparum (P = 0.036; OR = 2.493; 95% CI 1.104-4.551), and the DEL/DEL genotype of rs17880560 (TP53) was significantly more present in patients with mono-infection by P. vivax than in individuals with mixed infection (P = 0.029; OR = 0.667; 95% CI 0.211-1.669). CONCLUSIONS: In conclusion, variants in apoptosis genes are associated with malaria susceptibility and parasite density, indicating the role of apoptosis-related genetic profiles in immune responses against malaria infection.
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Coinfecção , Malária Falciparum , Malária Vivax , Parasitos , Humanos , Animais , Predisposição Genética para Doença , Brasil , Estudos de Casos e Controles , Apoptose/genética , Malária Vivax/genética , Malária Falciparum/genética , Plasmodium vivax/genética , Plasmodium falciparum/genéticaRESUMO
BACKGROUND: Malaria can be transmitted by blood transfusion through donations collected from asymptomatic or parasitic donors. The parasites are released into the bloodstream during its life cycle and will therefore be present in donated blood by infected individuals. All cases of transfusion-transmitted malaria (TTM) notified since 2005 in Brazil were fatal. A good screening tool for Plasmodium spp. detection in blood units must have a high detection threshold, and the prevention of TTM relies entirely on the exclusion of potentially infected donors. However, in Brazilian blood banks, the screening test relies on blood thick smears examination. METHODS: The molecular diagnostic based on mitochondrial DNA (mtDNA) using real time PCR (mt-qPCR) was improved to detect Plasmodium falciparum, Plasmodium vivax, and standardized for use in Plasmodium malariae. The analytic sensitivity of this mt-qPCR methodology was performed using a sample of P. vivax. RESULTS: The mt-qPCR was highly efficient, and the analytic sensitivity for P. vivax was determined (0.000006 parasites/µL). This method was tested to detect P. vivax and P. falciparum in individuals from two malaria-endemic areas in Brazil, Amazon region (Pará and Rondônia states), the samples were collected in 10 reference units of two blood banks (Pará/nine cities and Rondônia/Porto Velho), and parasites mtDNA were detected in 10 of 2224 potential blood donors (0.45%). In all 10 positive samples, only P. vivax was detected. CONCLUSION: Molecular diagnostic using mt-qPCR was effective in revealing infected potential donors with good perspectives to be applied as screening routine of asymptomatic carriers for preventing transfusion-transmitted malaria in blood banks.
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Bancos de Sangue , Transmissão de Doença Infecciosa/prevenção & controle , Malária/epidemiologia , Patologia Molecular , Vigilância em Saúde Pública/métodos , Sangue/parasitologia , Transfusão de Sangue , Brasil/epidemiologia , DNA Mitocondrial/análise , Humanos , Malária/parasitologia , Plasmodium falciparum/isolamento & purificação , Plasmodium malariae/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo RealRESUMO
BACKGROUND: The immune response against Plasmodium vivax immunogenic epitopes is regulated by pro- and anti-inflammatory cytokines that determine antibody levels and class switching. Cytokine gene polymorphisms may be responsible for changes in the humoral immune response against malaria. The aim of this study was to evaluate whether polymorphisms in the TNFA, IFNG and IL10 genes would alter the levels of anti-PvAMA1, PvDBP and -PvMSP-119 IgG antibodies in patients with vivax malaria. METHODS: Samples from 90 vivax malaria-infected and 51 uninfected subjects from an endemic area of the Brazilian Amazon were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to identify polymorphisms of the genes TNFA (-1031T > C, -308G > A, -238G > A), IFNG (+874T > A) and IL10 (-819C > T, -592C > A). The levels of total IgG against PvAMA1, PvDBP and PvMSP-119 were determined using an enzyme-linked immunosorbent assay (ELISA). Associations between the polymorphisms and the antibody response were assessed by means of logistic regression models. RESULTS: No significant differences were found in the levels of IgG antibodies against the PvAMA-1, PvDBP or PvMSP-119 proteins in relation to the studied polymorphisms. CONCLUSIONS: Although no associations were found among the evaluated genotypes and alleles and anti-merozoite IgG class P. vivax antibody levels, this study helps elucidate the immunogenic profile involved in the humoral immune response in malaria.
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Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Citocinas/genética , Proteínas de Membrana/imunologia , Plasmodium vivax/imunologia , Polimorfismo Genético , Proteínas de Protozoários/imunologia , Receptores de Superfície Celular/imunologia , Brasil , Ensaio de Imunoadsorção Enzimática , Estudos de Associação Genética , Técnicas de Genotipagem , Humanos , Imunoglobulina G/sangue , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de RestriçãoRESUMO
OBJECTIVE: To investigate the influence of IL6, IL12B and VDR single nucleotide polymorphisms (SNPs) in uncomplicated Plasmodium vivax infection symptoms intensity, parasitemia and gametocytemia levels in a Brazilian Amazonian population. METHODS: A total of 167 malaria patients infected by P. vivax have parasitemia and gametocytemia levels estimated before treatment. Fourteen clinical symptoms were evaluated and included in a principal component analysis to derive a clinical symptom index. Patients were genotyped for IL6-174C>G, IL12B 735T>C, 458A>G, 159A>C, and VDR FokI, TaqI, BsmI SNPs by Taqman 5' nuclease assays. A General Linear Model analysis of covariance with age, gender, exposure period and infection history and genetic ancestry was performed to investigate the association of genotypes with parasitemia and gametocytemia levels and with a clinical symptom index. RESULTS: Higher parasitemia levels were observed in IL6-174C carriers (p=0.02) whereas IL12B CGT haplotype carriers presented lower parasitemia levels (p=0.008). VDR TaqIC/BsmIA haplotype carriers showed higher gametocyte levels than non-carriers (p=0.013). Based on the clinical index values the IL6-174C>G polymorphism was associated with malaria severity. The IL6-174C carriers presented a more severe clinical index when compared to GG homozygotes (p=0.001). CONCLUSION: The present study suggests that IL6, IL12 and VDR influence severity, parasitemia and gametocytemia clearance in P. vivax infections, and highlights their potential role in malaria immune response in an Amazonian population.
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Subunidade p40 da Interleucina-12/genética , Interleucina-6/genética , Malária Vivax/genética , Parasitemia/genética , Plasmodium vivax , Receptores de Calcitriol/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Criança , Feminino , Genótipo , Humanos , Subunidade p40 da Interleucina-12/imunologia , Interleucina-6/imunologia , Malária Vivax/epidemiologia , Malária Vivax/imunologia , Masculino , Pessoa de Meia-Idade , Parasitemia/parasitologia , Polimorfismo de Nucleotídeo Único , Receptores de Calcitriol/imunologia , Adulto JovemRESUMO
Quilombo remnant communities are areas officially recognized by the Brazilian government as historical communities founded by formerly enslaved individuals. These communities are mostly located in the endemic areas of malaria in the Brazilian Amazon. We retrospectively described the prevalence of malaria among individuals living in 32 recognized quilombo remnant communities in the Baiao and Oriximina municipalities located in the Para State. The number of malaria cases and the Annual Parasitic Incidence (API) recorded by the Brazilian malaria surveillance system (SIVEP-Malaria) from January 2005 to December 2020 were analyzed. We found that all communities registered at least one case over the 16-year period, the most frequent parasitic species being Plasmodium vivax (76.1%). During this period, 0.44% (4,470/1,008,714) of the malaria cases registered in Para State were reported in these quilombo remnant communities, with frequencies of 10.9% (856/7,859) in Baiao municipality and 39.1% (3,614/9,238) in Oriximina municipality, showing that individuals living in these rural communities are exposed to malaria. These data indicate that effective surveillance requires improved measures to identify malaria transmission among vulnerable populations living in quilombo remnant communities in the Brazilian Amazon.
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Malária Vivax , Populações Vulneráveis , Humanos , Brasil/epidemiologia , Estudos Transversais , Estudos Retrospectivos , Prevalência , Malária Vivax/epidemiologia , Incidência , Feminino , Masculino , Adulto , População Rural , Adolescente , Malária/epidemiologia , Malária/transmissão , Adulto Jovem , Criança , Pessoa de Meia-Idade , Malária Falciparum/epidemiologia , Pré-EscolarRESUMO
BACKGROUND: When selecting blood donors in transfusion centres, one important problem is to identify, during screening, individuals with infectious diseases that can be transmitted by blood, such as malaria, especially when the parasite densities are very low. This problem is particularly severe in endemic areas, such as the Brazilian Amazon. In the present study, molecular diagnostic (real-time PCR) of Plasmodium vivax was used to identify blood donors infected with malaria parasites. METHODS: Samples from 595 blood donors were collected in seven haemotherapy centres in northern Brazil located in areas at risk for malaria transmission, and the analyses were performed by real-time PCR with TaqMan probes on 7500 Real-Time PCR Systems, to genotype the mitochondrial DNA region specific to P. vivax. The experiment was designed for hybridization of the cytochrome c oxidase genes of the mitochondrial genome (GenBank GI63022502). The serological data were obtained using enzyme-linked immunosorbent assay - ELISA (Anti-HIV, Anti-HTLV I-II; Anti-HVC, HBsAg, Anti-HBc, Chagas disease) and VDRL (Syphilis) from the Blood Bank System of the Haematology and Haemotherapy Centre of Pará. RESULTS: The assay identified eight individuals in the sample (1.34%) infected with P. vivax at the time of blood donation. This percentage was higher than the altered serological results (reactive or inconclusive) of the prevalence of anti-HIV (0.67%), anti-hepatitis C virus (0.34%), anti-hepatitis B surface antigen (0.67%), anti-human T-lymphotropic virus I/II (1.18%), anti-Chagas disease (0.17%) and syphilis (VDRL) (0.50%), but not higher than anti-hepatitis B core antigen antibodies (4.37%). This result indicates the need to use more sensitive methods of diagnosing malaria in blood banks. CONCLUSION: The real-time PCR with TaqMan probes enabled the identification of P. vivax in a high proportion of clinically healthy donors, highlighting the potential risk for transfusion-transmitted malaria. Additionally, this molecular diagnostic tool can be adopted as a new laboratory screening method in haemotherapy centres, especially in malaria-endemic areas.
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Malária Vivax/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Parasitemia/diagnóstico , Parasitologia/métodos , Plasmodium vivax/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Adolescente , Adulto , Idoso , Doadores de Sangue , Brasil , DNA Mitocondrial/genética , DNA de Protozoário/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Genótipo , Humanos , Malária Vivax/parasitologia , Masculino , Pessoa de Meia-Idade , Parasitemia/parasitologia , Plasmodium vivax/genética , Adulto JovemRESUMO
BACKGROUND: Malaria is among the most prevalent parasitic diseases worldwide. In Brazil, malaria is concentrated in the northern region, where Plasmodium vivax accounts for 85% disease incidence. The role of genetic factors in host immune system conferring resistance/susceptibility against P. vivax infections is still poorly understood. METHODS: The present study investigates the influence of polymorphisms in 18 genes related to the immune system in patients with malaria caused by P. vivax. A total of 263 healthy individuals (control group) and 216 individuals infected by P. vivax (malaria group) were genotyped for 33 single nucleotide polymorphisms (SNPs) in IL1B, IL2, IL4, IL4R, IL6, IL8, IL10, IL12A, IL12B, IL12RB1, SP110, TNF, TNFRSF1A, IFNG, IFNGR1, VDR, PTPN22 and P2X7 genes. All subjects were genotyped with 48 ancestry informative insertion-deletion polymorphisms to determine the proportion of African, European and Amerindian ancestry. Only 13 SNPs in 10 genes with differences lower than 20% between cases and controls in a Poisson Regression model with age as covariate were further investigated with a structured population association test. RESULTS: The IL1B gene -5839C > T and IL4R 1902A > G polymorphisms and IL12RB1 -1094A/-641C and TNF -1031 T/-863A/-857 T/-308 G/-238 G haplotypes were associated with malaria susceptibility after population structure correction (p = 0.04, p = 0.02, p = 0.01 and p = 0.01, respectively). CONCLUSION: Plasmodium vivax malaria pathophysiology is still poorly understood. The present findings reinforce and increase our understanding about the role of the immune system in malaria susceptibility.
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Interleucina-1beta/genética , Subunidade alfa de Receptor de Interleucina-4/genética , Malária Vivax/genética , Malária Vivax/imunologia , Receptores de Interleucina-12/genética , Fator de Necrose Tumoral alfa/genética , Adolescente , Adulto , Brasil/epidemiologia , Estudos de Casos e Controles , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Humanos , Malária Vivax/epidemiologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Adulto JovemRESUMO
BACKGROUND: In human malaria, the naturally-acquired immune response can result in either the elimination of the parasite or a persistent response mediated by cytokines that leads to immunopathology. The cytokines are responsible for all the symptoms, pathological alterations and the outcome of the infection depends on the reciprocal regulation of the pro and anti-inflammatory cytokines. IL-10 and IFN-gamma are able to mediate this process and their production can be affected by single nucleotide polymorphisms (SNPs) on gene of these cytokines. In this study, the relationship between cytokine IL-10/IFN-gamma levels, parasitaemia, and their gene polymorphisms was examined and the participation of pro-inflammatory and regulatory balance during a natural immune response in Plasmodium vivax-infected individuals was observed. METHODS: The serum levels of the cytokines IL-4, IL-12, IFN-gamma and IL-10 from 132 patients were evaluated by indirect enzyme-linked immunosorbent assays (ELISA). The polymorphism at position +874 of the IFN-gamma gene was identified by allele-specific polymerase chain reaction (ASO-PCR) method, and the polymorphism at position -1082 of the IL-10 gene was analysed by PCR-RFLP (PCR-Restriction Fragment Length Polymorphism). RESULTS: The levels of a pro- (IFN-gamma) and an anti-inflammatory cytokine (IL-10) were significantly higher in P. vivax-infected individuals as compared to healthy controls. The IFN-gamma levels in primoinfected patients were significantly higher than in patients who had suffered only one and more than one previous episode. The mutant alleles of both IFN-gamma and IL-10 genes were more frequent than the wild allele. In the case of the IFNG+874 polymorphism (IFN-gamma) the frequencies of the mutant (A) and wild (T) alleles were 70.13% and 29.87%, respectively. Similar frequencies were recorded in IL-10-1082, with the mutant (A) allele returning a frequency of 70.78%, and the wild (G) allele a frequency of 29.22%. The frequencies of the alleles associated with reduced production of both IFN-gamma and IL-10 were high, but this effect was only observed in the production of IFN-gamma. CONCLUSIONS: This study has shown evidence of reciprocal regulation of the levels of IL-10 and IFN-gamma cytokines in P. vivax malaria, which is not altered by the presence of polymorphism in the IL-10 gene.
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Interferon gama/sangue , Interleucina-10/sangue , Malária Vivax/imunologia , Adolescente , Adulto , Idoso , Alelos , Sangue/imunologia , Sangue/parasitologia , Criança , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Humanos , Interferon gama/genética , Interferons , Interleucina-10/genética , Masculino , Pessoa de Meia-Idade , Parasitemia/imunologia , Plasmodium vivax/imunologia , Reação em Cadeia da Polimerase , Polimorfismo Genético , Polimorfismo de Fragmento de Restrição , Regiões Promotoras Genéticas , Adulto JovemRESUMO
Plasmodium malariae infections are often asymptomatic and long-lasting. Mixed infections are often underdetected in areas where P. malariae, P. vivax, and P. falciparum are coendemic. In this study, we described the occurrence of these species circulating as single or mixed infections in Pará state, Brazil, in the Amazon region, with the purpose of clarifying the impact of misidentification of parasite species based only on morphological description using thick blood smear. By using real-time polymerase chain reaction based on the amplification of the mitochondrial DNA, we detected a prevalence of 46% (58/126) mixed infections with 33.3% P. malariae/P. vivax which were read as P. vivax monoinfections by microscopy detection. Our findings confirmed the high circulation of P. malariae in a malaria endemic area in the Brazilian Amazon region.
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Coinfecção/diagnóstico , Coinfecção/epidemiologia , Malária/diagnóstico , Malária/epidemiologia , Plasmodium falciparum/isolamento & purificação , Plasmodium malariae/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Brasil/epidemiologia , Doenças Endêmicas , Humanos , PrevalênciaRESUMO
[This corrects the article DOI: 10.1371/journal.pone.0113357.].
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Malaria is a human parasitic disease distributed in many tropical countries and caused by various Plasmodium species. Plasmodium vivax has the largest geographical distribution of the Plasmodium species and is predominant in the Americas, including Brazil. Only a small number of P. vivax vaccine formulations have successfully reached clinical trials relative to their P. falciparum counterparts. One of the candidate antigens for a blood-stage P. vivax vaccine is apical membrane antigen 1 (PvAMA-1). Due to the worldwide distribution of Plasmodium parasites, a high degree of variability has been detected in this antigen sequence, representing a considerable challenge to the development of a universal vaccine against malaria. In this study, we evaluated how PvAMA-1 polymorphisms influence vaccine-derived immune responses in P. vivax malaria. To this end, we expressed 9 recombinant protein representatives of different PvAMA-1 allelic variants in the yeast Pichia pastoris: Belem, Chesson I, Sal-1, Indonesia XIX, SK0814, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS. After protein expression and purification, we evaluated the breadth of the immune responses derived from malaria-exposed individuals from the Amazon region. From 611 serum samples of malaria-exposed individuals, 53.68% of them reacted against the PvAMA-1 Belem through ELISA. Positive samples were further tested against recombinant proteins representing the other PvAMA-1 allelic variants. Whereas Sal-1, Chesson I and SK0814 variants were highly recognized by tested serum samples, Indonesia XIX, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS were only slightly recognized. Moreover, polyclonal sera derived from C57BL/6 mice immunized with the PvAMA-1 Belem protein predominantly recognized Belem, Sal-1, Chesson I, SK0814, and Indonesia XIX through ELISA. Last, ELISA-based competition assays demonstrated that a previous interaction between anti-Belem polyclonal serum and Sal-1, Chesson I, SK0814, or Indonesia XIX proteins could further inhibit antibody binding to the Belem variant. Our human and mouse data suggest the presence of common epitopes or cross-reactivity between Belem, Sal-1, Chesson I, and SK0814 variants. Although the PvAMA-1 Belem variant induces strain-transcendent antibodies, PvAMA-1 variants from Thailand and Papua New Guinea may need to be included in a universal vaccine formulation to achieve protection against P. vivax malaria.
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Imunoglobulina G , Plasmodium vivax , Animais , Anticorpos Antiprotozoários , Antígenos de Protozoários/genética , Brasil , Epitopos , Camundongos , Camundongos Endogâmicos C57BL , Plasmodium vivax/genética , Proteínas de Protozoários/genética , Saccharomycetales , TailândiaRESUMO
BACKGROUND: Plasmodium vivax circumsporozoite variants have been identified in several geographical areas. The real implication of the genetic variation in this region of the P. vivax genome has been questioned for a long time. Although previous studies have observed significant association between VK210 and the Duffy blood group, we present here that evidences of this variation are limited to the CSP central portion. METHODS: The phylogenetic analyses were accomplished starting from the amplification of conserved domains of 18 SSU RNAr and Cyt B. The antibodies responses against the CSP peptides, MSP-1, AMA-1 and DBP were detected by ELISA, in plasma samples of individuals infected with two P. vivax CS genotypes: VK210 and P. vivax-like. RESULTS: These analyses of the two markers demonstrate high similarity among the P. vivax CS genotypes and surprisingly showed diversity equal to zero between VK210 and P. vivax-like, positioning these CS genotypes in the same clade. A high frequency IgG antibody against the N- and C-terminal regions of the P. vivax CSP was found as compared to the immune response to the R- and V- repetitive regions (p = 0.0005, Fisher's Exact test). This difference was more pronounced when the P. vivax-like variant was present in the infection (p = 0.003, Fisher's Exact test). A high frequency of antibody response against MSP-1 and AMA-1 peptides was observed for all P. vivax CS genotypes in comparison to the same frequency for DBP. CONCLUSIONS: This results target that the differences among the P. vivax CS variants are restrict to the central repeated region of the protein, mostly nucleotide variation with important serological consequences.
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Variação Genética , Proteína 1 de Superfície de Merozoito/genética , Plasmodium vivax/genética , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Citocromos b/genética , Genótipo , Humanos , Malária Vivax/parasitologia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Proteína 1 de Superfície de Merozoito/imunologia , Dados de Sequência Molecular , Filogenia , Plasmodium vivax/classificação , Reação em Cadeia da Polimerase , Proteínas de Protozoários/genética , Proteínas de Protozoários/imunologia , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/imunologia , Sequências Repetitivas de Ácido Nucleico , Análise de Sequência de DNARESUMO
Plasmodium vivax remains an important cause of malaria in South America and Asia, and analyses of the antibody immune response are being used to identify biomarker of parasite exposure. The IgG antibody naturally acquired predominantly occurs against targets on blood-stage parasites, including C-terminal of the merozoite surface protein 1 (MSP1-19). Epidemiological and immunological evidence has been showed that antibodies to malaria parasite antigens are lost in the absence of ongoing exposure. We describe the IgG antibody response in individuals living in an unstable malaria transmission area in Pará state, Amazon region, Brazil, where an epidemic of P. vivax malaria was recorded and monitored over time. As indicated by epidemiological data, the number of P. vivax-caused malaria cases decreased by approximately 90% after three years and the prevalence of IgG positive to PvMSP1-19 decreased significantly over time, in 2010 (93.4%), 2012 (78.3%), and 2013 (85.1%). Acquisition and decay of the IgG antibody against P. vivax MSP1-19 showed variability among individuals living in areas with recent circulating parasites, where the malaria epidemic was being monitored until transmission had been completely controlled. We also found that previous malaria episodes were associated with an increased in the IgG positivity . Our results showed epidemiological, spatial, temporal and individual variability. The understanding on dynamics of antibodies may have implications for the design of serosurveillance tools for monitoring parasite circulation, especially in a context with spatial and temporal changes in P. vivax malaria transmission.
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Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Imunoglobulina G/sangue , Malária Vivax/imunologia , Proteína 1 de Superfície de Merozoito/imunologia , Plasmodium vivax/imunologia , Adolescente , Adulto , Idoso , Anticorpos Antiprotozoários/imunologia , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Malária Vivax/transmissão , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
ABSTRACT Quilombo remnant communities are areas officially recognized by the Brazilian government as historical communities founded by formerly enslaved individuals. These communities are mostly located in the endemic areas of malaria in the Brazilian Amazon. We retrospectively described the prevalence of malaria among individuals living in 32 recognized quilombo remnant communities in the Baiao and Oriximina municipalities located in the Para State. The number of malaria cases and the Annual Parasitic Incidence (API) recorded by the Brazilian malaria surveillance system (SIVEP-Malaria) from January 2005 to December 2020 were analyzed. We found that all communities registered at least one case over the 16-year period, the most frequent parasitic species being Plasmodium vivax (76.1%). During this period, 0.44% (4,470/1,008,714) of the malaria cases registered in Para State were reported in these quilombo remnant communities, with frequencies of 10.9% (856/7,859) in Baiao municipality and 39.1% (3,614/9,238) in Oriximina municipality, showing that individuals living in these rural communities are exposed to malaria. These data indicate that effective surveillance requires improved measures to identify malaria transmission among vulnerable populations living in quilombo remnant communities in the Brazilian Amazon.
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AIM: The association of transporters gene polymorphisms with chloroquine/primaquine malaria treatment response was investigated in a Brazilian population. PATIENTS & METHODS: Totally, 164 Plasmodium vivax malaria infected patients were included. Generalized estimating equations were performed to determine gene influences on parasitemia and/or gametocytemia clearance over treatment time. RESULTS: Significant interaction between SLCO2B1 genotypes and treatment over time for parasitemia clearance rate on day 2 were observed (p FDR = 0.002). SLCO1A2 and SLCO1B1 gene treatment over time interactions were associated with gametocytemia clearance rate (p FDR = 0.018 and p FDR = 0.024). ABCB1, ABCC4 and SLCO1B3 were not associated with treatment response. CONCLUSION: The present work presents the first pharmacogenetic report of an association between chloroquine/primaquine responses with OATP transporters.
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Cloroquina/uso terapêutico , Transportador 1 de Ânion Orgânico Específico do Fígado/genética , Malária Vivax/genética , Transportadores de Ânions Orgânicos/genética , Polimorfismo Genético/genética , Primaquina/uso terapêutico , Adulto , Antimaláricos/uso terapêutico , Brasil , Quimioterapia Combinada/métodos , Feminino , Genótipo , Humanos , Malária Vivax/tratamento farmacológico , Masculino , Parasitemia/tratamento farmacológico , Parasitemia/genética , Plasmodium vivax/efeitos dos fármacos , Resultado do TratamentoRESUMO
BACKGROUND: Chloroquine/primaquine is the current therapy to eliminate Plasmodium vivax infection in the Amazon region. AIMS: This study investigates CYP1A2, CYP2C8, CYP2C9, CYP3A4 and CYP3A5 genetic polymorphisms influence on cloroquine/primaquine treatment. PATIENTS & METHODS: Generalized estimating equations analyses were performed to determine the genetic influence in parasitemia and/or gametocytemia clearance over treatment time in 164 patients. RESULTS: An effect of CYP2C8 low-activity alleles on treatment was observed (p = 0.01). From baseline to first day of treatment, wild-type individuals achieved greater reduction of gametocytes than low-activity allele carriers. CYP2C9 and CYP3A5 genes showed a trend for gametocytemia and parasitemia clearance rates. CONCLUSION: Future studies should be performed to access the extent of CYP2C8, CYP2C9 and CYP3A5 gene polymorphisms influence on cloroquine/primaquine treatment.
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The development of an effective immune response can help decrease mortality from malaria and its clinical symptoms. However, this mechanism is complex and has significant inter-individual variation, most likely owing to the genetic contribution of the human host. Therefore, this study aimed to investigate the influence of polymorphisms in genes involved in the costimulation of B-lymphocytes in the naturally acquired humoral immune response against proteins of the asexual stage of Plasmodium vivax. A total of 319 individuals living in an area of malaria transmission in the Brazilian Amazon were genotyped for four SNPs in the genes CD40, CD40L, BLYS and CD86. In addition, IgG antibodies against P. vivax apical membrane antigen 1 (PvAMA-1), Duffy binding protein (PvDBP) and merozoite surface protein 1 (PvMSP-119) were detected by ELISA. The SNP BLYS -871C>T was associated with the frequency of IgG responders to PvAMA-1 and PvMSP-119. The SNP CD40 -1C>T was associated with the IgG response against PvDBP, whereas IgG antibody titers against PvMSP-119 were influenced by the polymorphism CD86 +1057G>A. These data may help to elucidate the immunological aspects of vivax malaria and consequently assist in the design of malaria vaccines.
Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos CD , Imunoglobulina G/imunologia , Malária Vivax , Plasmodium vivax/imunologia , Polimorfismo de Nucleotídeo Único/imunologia , Proteínas de Protozoários/imunologia , Adolescente , Adulto , Idoso , Antígenos CD/genética , Antígenos CD/imunologia , Feminino , Humanos , Malária Vivax/genética , Malária Vivax/imunologia , Masculino , Pessoa de Meia-IdadeRESUMO
The pan HLA DR-binding epitope (PADRE) has been proposed as a simple carrier epitope suitable for use in the development of synthetic and recombinant vaccines. Using the mouse model, we evaluated whether PADRE could improve adjuvant-assisted immunizations with a recombinant malarial protein containing the 19kDa C-terminal region of merozoite surface protein 1 (MSP1(19)) that is a Plasmodium vivax vaccine candidate. Initially, the antibody immune response was evaluated in C57BL/6 mice, a mouse strain which develops a strong T cell immune response to PADRE. When administered in distinct adjuvant formulations, antibody titers induced by the recombinant protein His(6)MSP1(19)-PADRE were not significantly different to those generated by complete/incomplete Freund's adjuvant (CFA/IFA) in terms of magnitude, affinity, IgG subclasses and longevity. However, in C57BL/6 mice immunized with the recombinant protein His(6)MSP1(19), strong antibody responses could be generated in the presence of CFA/IFA but not other classes of adjuvants such as CpG ODN 1826 or MPL/TDM. Similarly, in BALB/c mice that do not develop T cells specific for PADRE, the recombinant protein His(6)MSP1(19)-PADRE failed to induce high antibody titers in the presence of adjuvants other than CFA/IFA. Our results indicated that when adjuvants that are not as strong as CFA/IFA are employed, the presence of PADRE greatly improved adjuvant-assisted antibody immune responses induced by a malarial recombinant antigen. Considering the great limitations of adjuvants for human use, our observation may improve the rational design of new vaccine formulations.
Assuntos
Epitopos/imunologia , Antígenos HLA-DR/imunologia , Vacinas Antimaláricas/imunologia , Malária Falciparum/prevenção & controle , Animais , Divisão Celular/imunologia , Humanos , Imunidade Celular/efeitos dos fármacos , Imunidade Celular/imunologia , Vacinas Antimaláricas/farmacologia , Malária Falciparum/imunologia , Camundongos , Plasmodium falciparum/imunologia , Especificidade do Receptor de Antígeno de Linfócitos T/imunologia , Linfócitos T/citologia , Linfócitos T/imunologiaRESUMO
BACKGROUND: Serological tests to detect antibodies specific to Plasmodium vivax could be a valuable tool for epidemiological studies, for screening blood donors in areas where the malaria is not endemic and for diagnosis of infected individuals. Because P. vivax cannot be easily obtained in vitro, ELISA assays using total or semi-purified antigens are rarely used. Based on this limitation, we tested whether recombinant proteins representing the 19 kDa C-terminal region of the merozoite surface protein-1 of P. vivax (MSP119) could be useful for serological detection of malaria infection. METHODS: Three purified recombinant proteins produced in Escherichia coli (GST-MSP119, His6-MSP119 and His6-MSP119-PADRE) and one in Pichia pastoris (yMSP119-PADRE) were compared for their ability to bind to IgG antibodies of individuals with patent P. vivax infection. The method was tested with 200 serum samples collected from individuals living in the north of Brazil in areas endemic for malaria, 53 serum samples from individuals exposed to Plasmodium falciparum infection and 177 serum samples from individuals never exposed to malaria. RESULTS: Overall, the sensitivity of the ELISA assessed with sera from naturally infected individuals was 95%. The proportion of serum samples that reacted with recombinant proteins GST-MSP119, His6-MSP119, His6-MSP119-PADRE and yMSP119-PADRE was 90%, 93.5%, 93.5% and 93.5%, respectively. The specificity values of the ELISA determined with sera from healthy individuals and from individuals with other infectious diseases were 98.3% (GST-MSP119), 97.7% (His6-MSP119 and His6-MSP119-PADRE) or 100% (yMSP119-PADRE). CONCLUSIONS: Our study demonstrated that for the Brazilian population, an ELISA using a recombinant protein of the MSP119 can be used as the basis for the development of a valuable serological assay for the detection of P. vivax malaria.
RESUMO
BACKGROUND: Measurement of malaria endemicity is typically based on vector or parasite measures. A complementary approach is the detection of parasite specific IgG antibodies. We determined the antibody levels and seroconversion rates to both P. vivax and P. falciparum merozoite antigens in individuals living in areas of varying P. vivax endemicity in Pará state, Brazilian Amazon region. METHODOLOGY/PRINCIPAL FINDINGS: The prevalence of antibodies to recombinant antigens from P. vivax and P. falciparum was determined in 1,330 individuals. Cross sectional surveys were conducted in the north of Brazil in Anajás, Belém, Goianésia do Pará, Jacareacanga, Itaituba, Trairão, all in the Pará state, and Sucuriju, a free-malaria site in the neighboring state Amapá. Seroprevalence to any P. vivax antigens (MSP1 or AMA-1) was 52.5%, whereas 24.7% of the individuals were seropositive to any P. falciparum antigens (MSP1 or AMA-1). For P. vivax antigens, the seroconversion rates (SCR) ranged from 0.005 (Sucuriju) to 0.201 (Goianésia do Pará), and are strongly correlated to the corresponding Annual Parasite Index (API). We detected two sites with distinct characteristics: Goianésia do Pará where seroprevalence curve does not change with age, and Sucuriju where seroprevalence curve is better described by a model with two SCRs compatible with a decrease in force of infection occurred 14 years ago (from 0.069 to 0.005). For P. falciparum antigens, current SCR estimates varied from 0.002 (Belém) to 0.018 (Goianésia do Pará). We also detected a putative decrease in disease transmission occurred â¼29 years ago in Anajás, Goianésia do Pará, Itaituba, Jacareacanga, and Trairão. CONCLUSIONS: We observed heterogeneity of serological indices across study sites with different endemicity levels and temporal changes in the force of infection in some of the sites. Our study provides further evidence that serology can be used to measure and monitor transmission of both major species of malaria parasite.