Article

Total and functional parasite specific IgE responses in Plasmodium falciparum-infected patients exhibiting different clinical status.

Instituto Gulbenkian de Ciencia, LEA CNRS-IGC, Oeiras, Portugal. <>
Malaria Journal (Impact Factor: 3.49). 02/2007; 6:1. DOI: 10.1186/1475-2875-6-1
Source: PubMed

ABSTRACT There is an increase of serum levels of IgE during Plasmodium falciparum infections in individuals living in endemic areas. These IgEs either protect against malaria or increase malaria pathogenesis. To get an insight into the exact role played by IgE in the outcome of P. falciparum infection, total IgE levels and functional anti-parasite IgE response were studied in children and adults, from two different endemic areas Gabon and India, exhibiting either uncomplicated malaria, severe non cerebral malaria or cerebral malaria, in comparison with control individuals.
Blood samples were collected from controls and P. falciparum-infected patients before treatment on the day of hospitalization (day 0) in India and, in addition, on days 7 and 30 after treatment in Gabon. Total IgE levels were determined by ELISA and functional P. falciparum-specific IgE were estimated using a mast cell line RBL-2H3 transfected with a human Fcepsilon RI alpha-chain that triggers degranulation upon human IgE cross-linking. Mann Whitney and Kruskall Wallis tests were used to compare groups and the Spearman test was used for correlations. Total IgE levels were confirmed to increase upon infection and differ with level of transmission and age but were not directly related to the disease phenotype. All studied groups exhibited functional parasite-specific IgEs able to induce mast cell degranulation in vitro in the presence of P. falciparum antigens. Plasma IgE levels correlated with those of IL-10 in uncomplicated malaria patients from Gabon. In Indian patients, plasma IFN-gamma , TNF and IL-10 levels were significantly correlated with IgE concentrations in all groups.
Circulating levels of total IgE do not appear to correlate with protection or pathology, or with anti-inflammatory cytokine pattern bias during malaria. On the contrary, the P. falciparum-specific IgE response seems to contribute to the control of parasites, since functional activity was higher in asymptomatic and uncomplicated malaria patients than in severe or cerebral malaria groups.

0 Followers
 · 
83 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Both helminth and malaria infections result in a highly polarized immune response characterized by IgE production. This study aimed to investigate the total serum IgE profile in vivo as a measure of Th2 immune response in malaria patients with and without helminth co-infection. Methods A cross sectional observational study composed of microscopically confirmed malaria positive (N = 197) and malaria negative (N = 216) apparently healthy controls with and without helminth infection was conducted at Wondo Genet Health Center, Southern Ethiopia. A pre-designed structured format was utilized to collect socio-demographic and clinical data of the subjects. Detection and quantification of helminths, malaria parasites and determination of serum IgE levels were carried out following standard procedures. Results Irrespective of helminth infection, individuals infected by malaria showed significantly high levels of serum IgE compared with malaria free apparently healthy controls (with and without helminth infections). Moreover, malaria patients co-infected with intestinal helminths showed high level of serum IgE compared with those malaria patients without intestinal helminths (2198 IU/ml versus 1668 IU/ml). A strong statistically significant association was observed between malaria parasite density and elevated serum IgE levels (2047 IU/ml versus 1778 IU/ml; P = 0.001) with high and low parasitaemia (parasite density >50,000 parasite/μl of blood), respectively. Likewise, helminth egg loads were significantly associated with elevated serum IgE levels (P = 0.003). Conclusions The elevated serum IgE response in malaria patients irrespective of helminth infection and its correlation with malaria parasite density and helminth egg intensity support that malaria infection is also a strong driver of IgE production as compared to helminths.
    Parasites & Vectors 05/2014; 7(1):240. DOI:10.1186/1756-3305-7-240 · 3.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background The modeling of malaria vector mosquito populations yields great insight into drivers of malaria transmission at the village scale. Simulation of individual mosquitoes as “agents” in a distributed, dynamic model domain may be greatly beneficial for simulation of spatial relationships of vectors and hosts. Methods In this study, an agent-based model is used to simulate the life cycle and movement of individual malaria vector mosquitoes in a Niger Sahel village, with individual simulated mosquitoes interacting with their physical environment as well as humans. Various processes that are known to be epidemiologically important, such as the dependence of parity on flight distance between developmental habitat and blood meal hosts and therefore spatial relationships of pools and houses, are readily simulated using this modeling paradigm. Impacts of perturbations can be evaluated on the basis of vectorial capacity, because the interactions between individuals that make up the population- scale metric vectorial capacity can be easily tracked for simulated mosquitoes and human blood meal hosts, without the need to estimate vectorial capacity parameters. Results As expected, model results show pronounced impacts of pool source reduction from larvicide application and draining, but with varying degrees of impact depending on the spatial relationship between pools and human habitation. Results highlight the importance of spatially-explicit simulation that can model individuals such as in an agent-based model. Conclusions The impacts of perturbations on village scale malaria transmission depend on spatial locations of individual mosquitoes, as well as the tracking of relevant life cycle events and characteristics of individual mosquitoes. This study demonstrates advantages of using an agent-based approach for village-scale mosquito simulation to address questions in which spatial relationships are known to be important.
    Parasites & Vectors 07/2014; 7(1):308. DOI:10.1186/1756-3305-7-308 · 3.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Anopheles dangi, introduced as a new species of the Hyrcanus Group of subgenus Anopheles in an illustrated dichotomous key for the identification of the Anopheles mosquitoes of Vietnam published in 1987, was distinguished from An. crawfordi based on the presence of a humeral pale spot on the base of costal vein of the wing. However, this character has been known to occur occasionally in An. crawfordi. To determine whether An. dangi is distinct from An. crawfordi, we analyzed nucleotide sequences of the COI, COII and Cyt-b genes of mtDNA and the D3 gene of rDNA obtained from specimens collected in south-central Vietnam that were identified as An. dangi and An. crawfordi based on the presence or absence, respectively, of a humeral pale spot. Maximum Likelihood and Bayesian analyses of the sequences showed a low mean genetic distance of 0.004 for specimens identified as An. crawfordi and 0.008 for those identified as An. dangi. The mean genetic distance between the two nominal species was 0.006, compared with 0.077 for any group versus the outgroup taxa An. dirus and An. minimus, and the specimens of the two forms clustered in a single strongly supported clade. Consequently, An. dangi is merely a morphological variant of An. crawfordi and is deemed to be a synonym of that nominal species.
    Acta tropica 09/2013; DOI:10.1016/j.actatropica.2013.09.004 · 2.52 Impact Factor

Full-text (3 Sources)

Download
21 Downloads
Available from
May 19, 2014