| 1. |
- Cherif, Mariama, et al.
(författare)
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Distribution of Fc gamma R gene polymorphisms among two sympatric populations in Mali : differing allele frequencies, associations with malariometric indices and implications for genetic susceptibility to malaria
- 2016
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Ingår i: Malaria Journal. - : Springer Science and Business Media LLC. - 1475-2875 .- 1475-2875. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genetic polymorphisms in the complex gene cluster encoding human Fc-gamma receptors (Fc gamma Rs) may influence malaria susceptibility and pathogenesis. Studying genetic susceptibility to malaria is ideal among sympatric populations because the distribution of polymorphic genes among such populations can help in the identification malaria candidate genes. This study determined the distribution of three FcyRs single nucleotide polymorphisms (SNPs) (Fc gamma RIIB-rs1050519, Fc gamma RIIC-rs3933769 and Fc gamma RIIIA-rs396991) among sympatric Fulani and Dogon children with uncomplicated malaria. The association of these SNPs with clinical, malariometric and immunological indices was also tested. Methods: This study involved 242 Fulani and Dogon volunteers from Mali age under 15 years. All SNPs were genotyped with predesigned TaqMan (R) SNP Genotyping Assays. Genotypic and allelic distribution of SNPs was compared across ethnic groups using the Fisher exact test. Variations in clinical, malariometric and immunologic indices between groups were tested with Kruskal-Wallis H, Mann-Whitney U test and Fisher exact test where appropriate. Results: The study confirmed known malariometric and immunologic differences between sympatric Fulani and non-Fulani tribes. Parasite density was lower in the Fulani than the Dogon (p < 0.0001). The mutant allele of Fc gamma RIIC (rs3933769) was found more frequently in the Fulani than the Dogon (p < 0.0001) while that of Fc gamma RIIIA (rs396991) occurred less frequently in the Fulani than Dogon (p = 0.0043). The difference in the mutant allele frequency of Fc gamma RIIB (rs1050519) between the two ethnic groups was however not statistically significant (p = 0.064). The mutant allele of rs396991 was associated with high malaria-specific IgG1 and IgG3 in the entire study population and Dogon tribe, p = 0.023 and 0.015, respectively. Parasite burden was lower in carriers of the Fc gamma RIIC (rs3933769) mutant allele than non-carriers in the entire study population (p < 0.0001). Carriers of this allele harboured less than half the parasites found in non-carriers. Conclusion: Differences in the allelic frequencies of rs3933769 and rs396991 among Fulani and Dogon indirectly suggest that these SNPs may influence malaria susceptibility and pathogenesis in the study population. The high frequency of the Fc gamma RIIC (rs3933769) mutant allele in the Fulani and its subsequent association with low parasite burden in the entire study population is noteworthy.
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| 2. |
- Quin, Jaclyn E., et al.
(författare)
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Major transcriptional changes observed in the Fulani, an ethnic group less susceptible to malaria
- 2017
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Ingår i: eLIFE. - 2050-084X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The Fulani ethnic group has relatively better protection from Plasmodium falciparum malaria, as reflected by fewer symptomatic cases of malaria, lower infection rates, and lower parasite densities compared to sympatric ethnic groups. However, the basis for this lower susceptibility to malaria by the Fulani is unknown. The incidence of classic malaria resistance genes are lower in the Fulani than in other sympatric ethnic populations, and targeted SNP analyses of other candidate genes involved in the immune response to malaria have not been able to account for the observed difference in the Fulani susceptibility to P.falciparum. Therefore, we have performed a pilot study to examine global transcription and DNA methylation patterns in specific immune cell populations in the Fulani to elucidate the mechanisms that confer the lower susceptibility to P.falciparum malaria. When we compared uninfected and infected Fulani individuals, in contrast to uninfected and infected individuals from the sympatric ethnic group Mossi, we observed a key difference: a strong transcriptional response was only detected in the monocyte fraction of the Fulani, where over 1000 genes were significantly differentially expressed upon P.falciparum infection.
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| 3. |
- Sanou, Guillaume S, et al.
(författare)
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Haematological parameters, natural regulatory CD4 + CD25 + FOXP3+ T cells and γδ T cells among two sympatric ethnic groups having different susceptibility to malaria in Burkina Faso.
- 2012
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Ingår i: BMC Research Notes. - : Springer Science and Business Media LLC. - 1756-0500. ; 5, s. 76-(12 pp)
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Fulani ethnic group individuals are less susceptible than sympatric Mossi ethnic group, in term of malaria infection severity, and differ in antibody production against malaria antigens. The differences in susceptibility to malaria between Fulani and Mossi ethnic groups are thought to be regulated by different genetic backgrounds and offer the opportunity to compare haematological parameters, Tregs and γδT cell profiles in seasonal and stable malaria transmission settings in Burkina Faso. The study was conducted at two different time points i.e. during the high and low malaria transmission period.RESULTS: Two cross-sectional surveys were undertaken in adults above 20 years belonging either to the Fulani or the Mossi ethnic groups 1) at the peak of the malaria transmission season and 2) during the middle of the low malaria transmission season. Full blood counts, proportions of Tregs and γδ T cells were measured at both time-points.As previously shown the Fulani and Mossi ethnic groups showed a consistent difference in P. falciparum infection rates and parasite load. Differential white blood cell counts showed that the absolute lymphocyte counts were higher in the Mossi than in the Fulani ethnic group at both time points. While the proportion of CD4+CD25high was higher in the Fulani ethnic group at the peak of malaria transmission season (p = 0.03), no clear pattern emerged for T regulatory cells expressing FoxP3+ and CD127low. However CD3+γδ+ subpopulations were found to be higher in the Fulani compared to the Mossi ethnic group, and this difference was statistically significant at both time-points (p = 0.004 at low transmission season and p = 0.04 at peak of transmission).CONCLUSION: Our findings on regulatory T cell phenotypes suggest an interesting role for immune regulatory mechanisms in response to malaria. The study also suggests that TCRγδ + cells might contribute to the protection against malaria in the Fulani ethnic group involving their reported parasite inhibitory activities.
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