| 1. |
- Winkler, Carla, et al.
(författare)
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Activation of group 2 innate lymphoid cells after allergen challenge in asthmatic patients
- 2019
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Ingår i: Journal of Allergy and Clinical Immunology. - : MOSBY-ELSEVIER. - 0091-6749 .- 1097-6825. ; 144:1, s. 61-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Group 2 innate lymphoid cells (ILC2s) are effective producers of IL-5 and IL-13 during allergic inflammation and bridge the innate and adaptive immune responses. ILC2 numbers are increased in asthmatic patients compared with healthy control subjects. Thus far, human data describing their phenotype during acute allergic inflammation in the lung are incomplete. Objectives: This study aims to characterize and compare blood and lung-derived ILC2s before and after segmental allergen challenge in patients with mild-to-moderate asthma with high blood eosinophil counts (amp;gt;= 300 cells/mu L). Methods: ILC2s were isolated from blood and bronchoalveolar lavage (BAL) fluid before and after segmental allergen challenge. Cells were sorted by means of flow cytometry, cultured and analyzed for cytokine release or migration, and sequenced for RNA expression. Results: ILC2s were nearly absent in the alveolar space under baseline conditions, but numbers increased significantly after allergen challenge (P amp;lt; .05), whereas at the same time, ILC2 numbers in blood were reduced (P amp;lt; .05). Prostaglandin D2 and CXCL12 levels in BAL fluid correlated with decreased ILC2 numbers in blood (P = .004, respective P = .024). After allergen challenge, several genes promoting type 2 inflammation were expressed at greater levels in BAL fluid compared with blood ILC2s, whereas blood ILC2s remain unactivated. Conclusion: ILC2s accumulate at the site of allergic inflammation and are recruited from the blood. Their transcriptional and functional activation pattern promotes type 2 inflammation.
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| 2. |
- Hjorton, Karin, et al.
(författare)
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Cytokine production by activated plasmacytoid dendritic cells and natural killer cells is suppressed by an IRAK4 inhibitor
- 2018
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Ingår i: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Background: In systemic lupus erythematosus (SLE), immune complexes (ICs) containing self-derived nucleic acids trigger the synthesis of proinflammatory cytokines by immune cells. We asked how an interleukin (IL)-1 receptor-associated kinase 4 small molecule inhibitor (IRAK4i) affects RNA-IC-induced cytokine production compared with hydroxychloroquine (HCQ).Methods: Plasmacytoid dendritic cells (pDCs) and natural killer (NK) cells were isolated from peripheral blood mononuclear cells (PBMCs) of healthy individuals. PBMCs from SLE patients and healthy individuals were depleted of monocytes. Cells were stimulated with RNA-containing IC (RNA-IC) in the presence or absence of IRAK4i I92 or HCQ, and cytokines were measured by immunoassay or flow cytometry. Transcriptome sequencing was performed on RNA-IC-stimulated pDCs from healthy individuals to assess the effect of IRAK4i and HCQ.Results: In healthy individuals, RNA-IC induced interferon (IFN)-α, tumor necrosis factor (TNF)-α, IL-6, IL-8, IFN-γ, macrophage inflammatory protein (MIP)1-α, and MIP1-β production in pDC and NK cell cocultures. IFN-α production was selective for pDCs, whereas both pDCs and NK cells produced TNF-α. IRAK4i reduced the pDC and NK cell-derived cytokine production by 74–95%. HCQ interfered with cytokine production in pDCs but not in NK cells. In monocyte-depleted PBMCs, IRAK4i blocked cytokine production more efficiently than HCQ. Following RNA-IC activation of pDCs, 975 differentially expressed genes were observed (false discovery rate (FDR) < 0.05), with many connected to cytokine pathways, cell regulation, and apoptosis. IRAK4i altered the expression of a larger number of RNA-IC-induced genes than did HCQ (492 versus 65 genes).Conclusions: The IRAK4i I92 exhibits a broader inhibitory effect than HCQ on proinflammatory pathways triggered by RNA-IC, suggesting IRAK4 inhibition as a therapeutic option in SLE.
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| 3. |
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| 4. |
- Israelsson, Elisabeth, et al.
(författare)
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Cytokine gene haplotypes with a potential effect on susceptibility to malaria in sympatric ethnic groups in Mali
- 2011
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Ingår i: Infection, Genetics and Evolution. - : Elsevier BV. - 1567-1348 .- 1567-7257. ; 11:7, s. 1608-1615
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Tidskriftsartikel (refereegranskat)abstract
- Cytokines are important players in the immune responses, and an unbalance in pro- and anti-inflammatory cytokine responses may affect parasitemia and pathology in a Plasmodium falciparum infection. Polymorphisms in cytokine genes may affect not only the levels of the protein, but many down-stream functions, such as production of C-reactive protein and immunoglobulin isotype switching. Susceptibility to malaria has been shown to differ between individuals with different genetic backgrounds, as indicated by studies in Fulani and non-Fulani ethnic groups. The aim of this study was to investigate possible interethnic differences in totally twelve single nucleotide polymorphisms (SNPs) in the genes encoding the cytokines IL-1β, IL-6, IL-10 and TNF. These SNPs are present in the promoter region of the genes, and have previously been associated with cytokine expression and with disease outcome in malaria. The results from the present study suggest that the Fulani ethnic group has a more pro-inflammatory response, due to high frequencies of high-producing alleles of IL1β and low-producing alleles of IL10. IL-6 could potentially also contribute to the relatively lower susceptibility to malaria in the Fulani ethnic group, whereas the TNF polymorphisms analysed in this study rather seem to associate with the severity of the infection and not the susceptibility for the infection itself. We therefore suggest that the polymorphisms analysed in this study all show a potential to influence the relatively lower susceptibility to malaria seen in the Fulani ethnic group as compared to the other sympatric ethnic groups.
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| 5. |
- Lokki, A Inkeri, et al.
(författare)
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Lactase persistence genotypes and malaria susceptibility in Fulani of Mali.
- 2011
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Ingår i: Malaria Journal. - : Springer Science and Business Media LLC. - 1475-2875 .- 1475-2875. ; 10, s. 9-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Fulani are a widely spread African ethnic group characterized by lower susceptibility to Plasmodium falciparum, clinical malaria morbidity and higher rate of lactase persistence compared to sympatric tribes. Lactase non-persistence, often called lactose intolerance, is the normal condition where lactase activity in the intestinal wall declines after weaning. Lactase persistence, common in Europe, and in certain African people with traditions of raising cattle, is caused by polymorphisms in the enhancer region approximately 14 kb upstream of the lactase gene. METHODS: To evaluate the relationship between malaria and lactase persistence genotypes, a 400 bp region surrounding the main European C/T-13910 polymorphism upstream of the lactase gene was sequenced. DNA samples used in the study originated from 162 Fulani and 79 Dogon individuals from Mali. RESULTS: Among 79 Dogon only one heterozygote of the lactase enhancer polymorphism was detected, whereas all others were homozygous for the ancestral C allele. Among the Fulani, the main European polymorphism at locus C/T-13910 was by far the most common polymorphism, with an allele frequency of 37%. Three other single-nucleotide polymorphisms were found with allele frequencies of 3.7%, 1.9% and 0.6% each. The novel DNA polymorphism T/C-13906 was seen in six heterozygous Fulani. Among the Fulani with lactase non-persistence CC genotypes at the C/T-13910 locus, 24% had malaria parasites detectable by microscopy compared to 18% for lactase persistent genotypes (P = 0.29). Pooling the lactase enhancer polymorphisms to a common presumptive genotype gave 28% microscopy positives for non-persistent and 17% for others (P = 0.11). CONCLUSIONS: Plasmodium falciparum parasitaemia in asymptomatic Fulani is more common in individuals with lactase non-persistence genotypes, but this difference is not statistically significant. The potential immunoprotective properties of dietary cow milk as a reason for the partial malaria resistance of Fulani warrant further investigation.
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| 6. |
- Giha, Hayder A, et al.
(författare)
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Association of a single nucleotide polymorphism in the C-reactive protein gene (-286) with susceptibility to Plasmodium falciparum malaria
- 2010
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Ingår i: Molecular Medicine. - : Springer Science and Business Media LLC. - 1076-1551 .- 1528-3658. ; 16:1-2, s. 27-33
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Tidskriftsartikel (refereegranskat)abstract
- The role of inflammation in malaria pathogenesis is not fully understood, although C-reactive protein (CRP) may have a negative influence on host immunity to infections. An upstream polymorphism, -286 (C > T > A), in the CRP gene is known to influence CRP levels. In this study, a cohort of 192 Sudanese donors, followed for malaria infection for 9 years, had their CRP -286 gene locus genotyped by pyrosequencing. The number of malaria episodes experienced by each individual over the study period was used as an index for malaria susceptibility. The prevalence of the CRP alleles A, C and T were 21%, 52% and 27%, respectively. Importantly, the A-allele, unlike the C- and T-alleles or CRP genotypes, was significantly associated with an increased number of malaria episodes, P = 0.007. The proportion of A-allele carriers among donors not known to have had malaria during the study period was 18%, whereas it was 43% and 63% among donors who had experienced 1-4 and > or =5 malaria episodes, respectively, over the same period (P = 0.002). Furthermore, the A-allele was associated with higher parasite counts. In conclusion, the CRP -286 A-allele was associated with an increased susceptibility to uncomplicated Plasmodium falciparum malaria.
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| 7. |
- Israelsson, Elisabeth, et al.
(författare)
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Marked differences in CRP genotype frequencies between the Fulani and sympatric ethnic groups in Africa
- 2009
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Ingår i: Malaria Journal. - : Springer Science and Business Media LLC. - 1475-2875 .- 1475-2875. ; 8:136
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Tidskriftsartikel (refereegranskat)abstract
- Background C-reactive protein (CRP) is an acute phase protein that can activate various immune cells and bind to certain Fcγ receptors. The latter may compete with the binding of IgG antibodies to these receptors and could thereby interfere with the antigen-specific immune response. Polymorphisms in the promoter region of the CRP gene have been strongly associated with the plasma concentration of CRP. The known lower susceptibility to malaria in the Fulani ethnic group, as compared to their sympatric neighbours in Africa, has been linked to different genetic backgrounds. The present study was performed to investigate if polymorphisms in the CRP gene could contribute to the lower susceptibility to malaria seen in the Fulani ethnic group. Methods The CRP -717 T>C, -286 C>T>A, and +1444 C>T polymorphisms were analysed in asymptomatic Fulani and non-Fulani individuals from Mali and Sudan using Pyrosequencing T and TaqMan r MGB probes. Results The rare -286 A allele, previously shown to be associated with increased CRP expression and plasma levels, was shown to be more frequent in the non-Fulani ethnic groups as compared to the sympatric Fulani ethnic group both in Mali and Sudan. The common -717 T allele was more prevalent in the non-Fulani ethnic group compared to the sympatric Fulani ethnic group, but only in Mali. The parasite prevalence was increased for the -286 A allele, but not for the -717 T allele. No differences regarding genotype frequency or parasite prevalence were seen for +1444 C>T. Conclusion This study indicate that CRP may play an important role in the immune responses to malaria, and that the -286 C/T/A CRP polymorphism may be a contributing factor to the lower susceptibility to malaria seen in the Fulani.
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| 8. |
- Vafa, Manijeh, et al.
(författare)
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Impact of the IL-4 -590 C/T transition on the levels of Plasmodium falciparum specific IgE, IgG, IgG subclasses and total IgE in two sympatric ethnic groups living in Mali.
- 2009
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Ingår i: Microbes and infection. - : Elsevier BV. - 1286-4579 .- 1769-714X. ; 11:8-9, s. 779-84
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to examine the effect of IL-4 -590 T/C polymorphism on the levels of malaria-specific IgE, IgG, IgG (1-4) subclasses as well as total IgE in the Fulani and their sympatric ethnic group, the Dogon, in Mali. Asymptomatic individuals, of the Fulani and the Dogon ethnic groups, were included in the study. IL-4 is involved in the regulation of IgE and IgG4 subclass. In line with this we found that within the Fulani, the T allele was associated with increased levels of total and anti-malarial IgE (P=0.02 and P=0.04, respectively). The Fulani T allele carriers had slightly higher levels of malarial specific IgG4 as compared to those with the CC genotype (P=0.08). No such differences were observed amongst the Dogon individuals. Taken together, these data indicate that the impact of IL-4 -590 variants on antibody levels may vary in different ethnic populations, and that this might affect the Ig-class and subclass distributions.
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| 9. |
- Vafa, Manijeh, et al.
(författare)
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Relationship between immunoglobulin isotype response to Plasmodium falciparum blood stage antigens and parasitological indexes as well as splenomegaly in sympatric ethnic groups living in Mali
- 2009
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Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X .- 1873-6254. ; 9:1, s. 12-16
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to assess correlations between anti-malarial antibody levels and differences in malariometric characteristics, seen between two sympatric ethnic groups, the Fulani and the Dogon, living in Mali. Plasma levels of anti-malarial IgE, IgG. IgG1-4 and total IgE were determined in asymptomatic individuals, of the above mentioned groups, and were correlated to malariometric indexes. Significantly higher levels of anti-malarial IgE, IgG, IgG1-3 and total IgE were detected in the Fulani individuals as compared to the Dogon. No difference in plasma levels of malaria specific IgG4 was noted between the two groups. Within the Fulani, an increase in total IgE levels was associated with the presence of infection. As the IgG4 level increased, the number of clones decreased in the Fulani individuals. A positive correlation between elevated levels of anti-malarial IgG and IgG3 and splenomegaly was noted only within the Fulani group. No other correlations between antibody levels and parasite prevalence, clone numbers or spleen rates were observed in any of the communities. These results suggest that the magnitude of antibody response against Plasmodium falciparum may not be as important as it is believed to be. Instead, the fine specificity or function of the response might be more critical in protection against malaria disease.
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| 10. |
- Israelsson, Elisabeth, 1979-
(författare)
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Host genetic factors and antibody responses with potential involvement in the susceptibility to malaria
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The relatively lower susceptibility to malaria seen in the Fulani ethnic group in Africa, as compared to other sympatric ethnic groups, has been related to genetic regulation of the immune responses. This thesis aimed to describe important pathways related to the regulation of antibodies in the immune responses during a malaria infection. Our results suggest that the higher anti-malarial immune responses seen in the Fulani are not a general hyper-responsiveness in this group, but neither a malaria specific response. Fcγ receptors are important structures in the immune responses, and polymorphisms in these genes were associated with IgG subclass levels, P. falciparum parasitemia and haemoglobin levels, suggesting that these polymorphisms may be a contributing factor to the differential susceptibility to malaria. C-reactive protein levels rise immediately in response to inflammatory stimuli, and the -286 CRP polymorphism was indicated to influence parasite levels, suggesting a possible involvement in the lower susceptibility to malaria seen in the Fulani ethnic group. Several cytokines are important in maintaining the optimal parasite-neutralizing milieu in the host, and we investigated polymorphisms in some of these cytokine genes, in order to establish a possible influence of these on malaria susceptibility. Several of these polymorphisms showed associations with haemoglobin levels, IgG subclass antibody levels and parasitemia, suggesting that IL-1β, IL-6, IL-10 and TNF could affect the susceptibility to malaria and the severity of the malaria infection.Taken together, these data suggest that genetic factors have the ability to affect the antibody responses, and that several pathways can be affected. Moreover, the Fulani have a genetic predisposition for a higher inflammatory response during a malaria infection, which could lower their susceptibility to the disease. However, the control measures for this inflammation still have to be established and evaluated.
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