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Malaria resistance genes are associated with the levels of IgG subclasses directed against Plasmodium falciparum blood-stage antigens in Burkina Faso.

ABSTRACT: BACKGROUND: HBB, IL4, IL12, TNF, LTA, NCR3 and FCGR2A polymorphisms have been associated with malaria resistance in humans, whereas cytophilic immunoglobulin G (IgG) antibodies are thought to play a critical role in immune protection against asexual blood stages of the parasite. Furthermore, HBB, IL4, TNF, and FCGR2A have been associated with both malaria resistance and IgG levels. This suggests that some malaria resistance genes influence the levels of IgG subclass antibodies. METHODS: In this study, the effect of HBB, IL4, IL12, TNF, LTA, NCR3 and FCGR2A polymorphisms on the levels of IgG responses against Plasmodium falciparum blood-stage extract was investigated in 220 individuals living in Burkina Faso. The Pearson's correlation coefficient among IgG subclasses was determined. A family-based approach was used to assess the association of polymorphisms with anti-P. falciparum IgG, IgG1, IgG2, IgG3 and IgG4 levels. RESULTS: After applying a multiple test correction, several polymorphisms were associated with IgG subclass or IgG levels. There was an association of i) haemoglobin C with IgG levels; ii) the Fc?RIIa H/R131 with IgG2 and IgG3 levels; iii) TNF-863 with IgG3 levels; iv) TNF-857 with IgG levels; and, v) TNF1304 with IgG3, IgG4, and IgG levels. CONCLUSION: Taken together, the results support the hypothesis that some polymorphisms affect malaria resistance through their effect on the acquired immune response, and pave the way towards further comprehension of genetic control of an individual's humoral response against malaria.

SUBMITTER: Afridi S

PROVIDER: S-EPMC3552815 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Malaria resistance genes are associated with the levels of IgG subclasses directed against Plasmodium falciparum blood-stage antigens in Burkina Faso.

Afridi Sarwat S Atkinson Alexandre A Garnier Séverine S Fumoux Francis F Rihet Pascal P

Malaria journal 20120904

<h4>Background</h4>HBB, IL4, IL12, TNF, LTA, NCR3 and FCGR2A polymorphisms have been associated with malaria resistance in humans, whereas cytophilic immunoglobulin G (IgG) antibodies are thought to play a critical role in immune protection against asexual blood stages of the parasite. Furthermore, HBB, IL4, TNF, and FCGR2A have been associated with both malaria resistance and IgG levels. This suggests that some malaria resistance genes influence the levels of IgG subclass antibodies.<h4>Methods ...[more]

PMID: 22947458

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Project description:BACKGROUND: Malaria during pregnancy remains a serious public health problem. The aim of this study was to determine the prevalence and possible risk factors for malaria in pregnant women attending antenatal clinic at two primary health facilities in Bobo-Dioulasso. METHODS: We conducted a cross sectional study from September to December 2010 in two primary health facilities located in the periurban area of Bobo-Dioulasso. Pregnant women attending antenatal clinic (ANC) were included in the study after signing informed consent. For each participant, the social-demographic profile, malaria and obstetric histories were investigated through a questionnaire. Peripheral blood was collected and thick and thin blood smears were prepared to check Plasmodium falciparum parasitaemia. Hemoglobin concentration was measured. The associations between age, parity, gestational age, schooling, number of ANC visits, use of IPTp-SP, use of insecticide-treated nets (ITN) and anemia with the occurrence of P. falciparum malaria infection during pregnancy were analyzed through logistic regression. RESULTS: During the period of study, 105 (18.1%) out of 579 pregnant women were infected by P. falciparum. The hemoglobin concentration mean was 10.5?±?1.7/dL and was significantly lower in pregnant women with malaria infection (9.8 g/dL ±1.6) than in those who had no malaria infection (10.6 g/dL ±1.7) (P?<?0.001). Multivariate analysis indicated that, education (AOR 1.9, 95% CI?=?[1.2-3.2]), parity [primigravidae (AOR 5.0, 95% CI?=?[2.5-9.8]) and secundigravidae (AOR 2.1, 95% CI?=?[1.2-3.8])], and anaemia (AOR 2.1, 95% CI?=?[1.3-3.5]) were significantly associated with P. falciparum malaria infection. The use of IPTp-SP was not associated with P. falciparum malaria infection. CONCLUSIONS: P. falciparum malaria infection is common in pregnant women attending antenatal clinic and anaemia is an important complication. The results show that the use of IPTp-SP does not reduce the risk of malaria incidence during pregnancy.

Project description:BackgroundInvestigating malaria transmission dynamics is essential to inform policy decision making. Whether multiplicity of infection (MOI) dynamic from individual infections could be a reliable malaria metric in high transmission settings with marked variation in seasons of malaria transmission has been poorly assessed. This study aimed at investigating factors driving Plasmodium falciparum MOI and genetic diversity in a hyperendemic area of Burkina Faso.MethodsBlood samples collected from a pharmacovigilance trial were used for polymerase chain reaction genotyping of the merozoite surface proteins 1 and 2. MOI was defined as the number of distinct parasite genotypes co-existing within a particular infection. Monthly rainfall data were obtained from satellite data of the Global Precipitation Measurement Database while monthly malaria incidence aggregated data were extracted from District Health Information Software 2 medical data of the Center-West health regional direction.ResultsIn the study area, infected people harboured an average of 2.732 (± 0.056) different parasite genotypes. A significant correlation between the monthly MOI and the monthly malaria incidence was observed, suggesting that MOI could be a good predictor of transmission intensity. A strong effect of season on MOI was observed, with infected patients harbouring higher number of parasite genotypes during the rainy season as compared to the dry season. There was a negative relationship between MOI and host age. In addition, MOI decreased with increasing parasite densities, suggesting that there was a within-host competition among co-infecting genetically distinct P. falciparum variants. Each allelic family of the msp1 and msp2 genes was present all year round with no significant monthly fluctuation.ConclusionsIn high malaria endemic settings with marked variation in seasons of malaria transmission, MOI represents an appropriate malaria metric which provides useful information about the longitudinal changes in malaria transmission in a given area. Besides transmission season, patient age and parasite density are important factors to consider for better understanding of variations in MOI. All allelic families of msp1 and msp2 genes were found in both dry and rainy season. The approach offers the opportunity of translating genotyping data into relevant epidemiological information for malaria control.

Project description:Pregnant women exposed to Plasmodium falciparum generate antibodies against VAR2CSA, the parasite protein that mediates adhesion of infected erythrocytes to the placenta. There is a need of high-throughput tools to determine the fine specificity of these antibodies that can be used to identify immune correlates of protection and exposure. Here we aimed at developing a multiplex-immunoassay to detect antibodies against VAR2CSA antigens.We constructed two multiplex-bead arrays, one composed of 3 VAR2CSA recombinant-domains (DBL3X, DBL5? and DBL6?) and another composed of 46 new peptides covering VAR2CSA conserved and semi-conserved regions. IgG reactivity was similar in multiplexed and singleplexed determinations (Pearson correlation, protein array: R2 = 0.99 and peptide array: R2 = 0.87). IgG recognition of 25 out of 46 peptides and all recombinant-domains was higher in pregnant Mozambican women (n = 106) than in Mozambican men (n = 102) and Spanish individuals (n = 101; p<0.05). Agreement of IgG levels detected in cryopreserved plasma and in elutions from dried blood spots was good after exclusion of inappropriate filter papers. Under heterogeneous levels of exposure to malaria, similar seropositivity cutoffs were obtained using finite mixture models applied to antibodies measured on pregnant Mozambican women and average of antibodies measured on pregnant Spanish women never exposed to malaria. The application of the multiplex-bead array developed here, allowed the assessment of higher IgG levels and seroprevalences against VAR2CSA-derived antigens in women pregnant during 2003-2005 than during 2010-2012, in accordance with the levels of malaria transmission reported for these years in Mozambique.The multiplex bead-based immunoassay to detect antibodies against selected 25 VAR2CSA new-peptides and recombinant-domains was successfully implemented. Analysis of field samples showed that responses were specific among pregnant women and dependent on the level of exposure to malaria. This platform provides a high-throughput approach to investigating correlates of protection and identifying serological markers of exposure for malaria in pregnancy.

Dataset Information

Malaria resistance genes are associated with the levels of IgG subclasses directed against Plasmodium falciparum blood-stage antigens in Burkina Faso.

Publications

Malaria resistance genes are associated with the levels of IgG subclasses directed against Plasmodium falciparum blood-stage antigens in Burkina Faso.

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