| 1. |
- Blomgran, Robert, et al.
(författare)
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Common Genetic Variations in the NALP3 Inflammasome Are Associated with Delayed Apoptosis of Human Neutrophils
- 2012
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Ingår i: PLOS ONE. - San Francisco, USA : Public Library of Science. - 1932-6203. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neutrophils are key-players in the innate host defense and their programmed cell death and removal are essential for efficient resolution of inflammation. These cells recognize a variety of pathogens, and the NOD-like receptors (NLRs) have been suggested as intracellular sensors of microbial components and cell injury/stress. Some NLR will upon activation form multi-protein complexes termed inflammasomes that result in IL-1 beta production. NLR mutations are associated with auto-inflammatory syndromes, and our previous data propose NLRP3 (Q705K)/CARD-8 (C10X) polymorphisms to contribute to increased risk and severity of inflammatory disease by acting as genetic susceptibility factors. These gene products are components of the NALP3 inflammasome, and approximately 6.5% of the Swedish population are heterozygote carriers of these combined gene variants. Since patients carrying the Q705K/C10X polymorphisms display leukocytosis, the aim of the present study was to find out whether the inflammatory phenotype was related to dysfunctional apoptosis and impaired clearance of neutrophils by macrophages. less thanbrgreater than less thanbrgreater thanMethods and Findings: Patients carrying the Q705K/C10X polymorphisms displayed significantly delayed spontaneous as well as microbe-induced apoptosis compared to matched controls. Western blotting revealed increased levels and phosphorylation of Akt and Mcl-1 in the patients neutrophils. In contrast to macrophages from healthy controls, macrophages from the patients produced lower amounts of TNF; suggesting impaired macrophage clearance response. less thanbrgreater than less thanbrgreater thanConclusions: The Q705K/C10X polymorphisms are associated with delayed apoptosis of neutrophils. These findings are explained by altered involvement of different regulators of apoptosis, resulting in an anti-apoptotic profile. Moreover, the macrophage response to ingestion of microbe-induced apoptotic neutrophils is altered in the patients. Taken together, the patients display impaired turnover and clearance of apoptotic neutrophils, pointing towards a dysregulated innate immune response that influences the resolution of inflammation. The future challenge is to understand how microbes affect the activation of inflammasomes, and why this interaction will develop into severe inflammatory disease in certain individuals.
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| 2. |
- Dahlqvist, Johanna, 1979-, et al.
(författare)
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Identification and functional characterization of a novel susceptibility locus for small vessel vasculitis with MPO-ANCA
- 2022
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Ingår i: Rheumatology. - Oxford, United Kingdom : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 61:8
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Tidskriftsartikel (refereegranskat)abstract
- Objective To identify and characterize genetic loci associated with the risk of developing ANCA-associated vasculitides (AAV). Methods Genetic association analyses were performed after Illumina sequencing of 1853 genes and subsequent replication with genotyping of selected single nucleotide polymorphisms in a total cohort of 1110 Scandinavian cases with granulomatosis with polyangiitis or microscopic polyangiitis, and 1589 controls. A novel AAV-associated single nucleotide polymorphism was analysed for allele-specific effects on gene expression using luciferase reporter assay. Results PR3-ANCA(+) AAV was significantly associated with two independent loci in the HLA-DPB1/HLA-DPA1 region [rs1042335, P = 6.3 x 10(-61), odds ratio (OR) 0.10; rs9277341, P = 1.5 x 10(-44), OR 0.22] and with rs28929474 in the SERPINA1 gene (P = 2.7 x 10(-10), OR 2.9). MPO-ANCA(+) AAV was significantly associated with the HLA-DQB1/HLA-DQA2 locus (rs9274619, P = 5.4 x 10(-25), OR 3.7) and with a rare variant in the BACH2 gene (rs78275221, P = 7.9 x 10(-7), OR 3.0), the latter a novel susceptibility locus for MPO-ANCA(+) granulomatosis with polyangiitis/microscopic polyangiitis. The rs78275221-A risk allele reduced luciferase gene expression in endothelial cells, specifically, as compared with the non-risk allele. Conclusion We identified a novel susceptibility locus for MPO-ANCA(+) AAV and propose that the associated variant is of mechanistic importance, exerting a regulatory function on gene expression in specific cell types.
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| 3. |
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| 4. |
- Kastbom, Alf, et al.
(författare)
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Genetic variation in proteins of the cryopyrin inflammasome influences susceptibility and severity of rheumatoid arthritis (the Swedish TIRA project)
- 2008
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 47:4, s. 415-417
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The genetic background to RA is incompletely understood.As new cytokine-targeted therapies emerge, early predictorsof disease severity are becoming increasingly important. Theinflammasomes are essential regulators of cytokine production.We investigated whether two polymorphisms in the genes encodingcryopyrin (CIAS1) and TUCAN (CARD8) influence susceptibilityand disease course in RA. Methods: Genotype frequencies were assessed in 174 Swedish patientswith early RA and 360 population-based controls without rheumaticdisease. Genotypes were categorized according to the presence(+) or absence (–) of two wild-type alleles and comparedbetween patients and controls. In the RA patients, antibodiestowards cyclic citrullinated peptides (anti-CCP) and the ‘sharedepitope’ (SE) were assessed, and medication and measuresof disease activity were monitored regularly during 3 yrs. Results: The combination of CIAS1/TUCAN –/–, ascompared with CIAS1/TUCAN +/+, was significantly more commonamong patients than in controls [odds ratio (OR) 2.2, 95% CI1.03–4.6]. This association was strengthened when patientswere divided into anti-CCP+ [OR 2.8 (1.1–6.7)] or presenceof 1 SE copy [OR 2.8 (1.3–6.2)]. At most time-points duringthe 3-yr follow-up, patients with CIAS1/TUCAN –/–showed significantly higher disease activity. Furthermore, CIAS1/TUCAN–/– patients proved to be much more likely to receiveTNF-blocking therapy [relative risk 20 (2.6–149)]. Conclusions: Compound polymorphisms in CIAS1 and TUCAN associatewith RA susceptibility and severity. The cryopyrin inflammasomeneeds further attention regarding a possible aetiopathogeneticconnection with RA.
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| 5. |
- Lundtoft, Christian, et al.
(författare)
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The HLA region in ANCA-associated vasculitis : characterisation of genetic associations in a Scandinavian patient population
- 2024
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Ingår i: RMD Open. - : BMJ Publishing Group Ltd. - 2056-5933. ; 10:2, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are inflammatory disorders with ANCA autoantibodies recognising either proteinase 3 (PR3-AAV) or myeloperoxidase (MPO-AAV). PR3-AAV and MPO-AAV have been associated with distinct loci in the human leucocyte antigen (HLA) region. While the association between MPO-AAV and HLA has been well characterised in East Asian populations where MPO-AAV is more common, studies in populations of European descent are limited. The aim of this study was to thoroughly characterise associations to the HLA region in Scandinavian patients with PR3-AAV as well as MPO-AAV.METHODS: Genotypes of single-nucleotide polymorphisms (SNPs) located in the HLA region were extracted from a targeted exome-sequencing dataset comprising Scandinavian AAV cases and controls. Classical HLA alleles were called using xHLA. After quality control, association analyses were performed of a joint SNP/classical HLA allele dataset for cases with PR3-AAV (n=411) and MPO-AAV (n=162) versus controls (n=1595). Disease-associated genetic variants were analysed for association with organ involvement, age at diagnosis and relapse, respectively.RESULTS: PR3-AAV was significantly associated with both HLA-DPB1*04:01 and rs1042335 at the HLA-DPB1 locus, also after stepwise conditional analysis. MPO-AAV was significantly associated with HLA-DRB1*04:04. Neither carriage of HLA-DPB1*04:01 alleles in PR3-AAV nor of HLA-DRB1*04:04 alleles in MPO-AAV were associated with organ involvement, age at diagnosis or relapse. CONCLUSIONS: The association to the HLA region was distinct in Scandinavian cases with MPO-AAV compared with cases of East Asian descent. In PR3-AAV, the two separate signals of association to the HLD-DPB1 region mediate potentially different functional effects.
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| 6. |
- Mathioudaki, Argyri, Ph.D student, 1986-, et al.
(författare)
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Allele frequency spectrum of known ankylosing spondylitis associated variants in a Swedish population
- 2022
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Ingår i: Scandinavian Journal of Rheumatology. - : Informa UK Limited. - 0300-9742 .- 1502-7732. ; 51:1, s. 21-24
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The genetic predisposition to ankylosing spondylitis (AS) has been most widely studied in cohorts with European ancestry. However, within Europe, disease prevalence is higher in Sweden. Given this, we aimed to characterize known AS susceptibility variants in a homogeneous Swedish data set, assessing reproducibility and direction of effect. Method: The power to detect association within an existing Swedish targeted sequencing study (381 controls; 310 AS cases) was examined, and a set of published associations (n = 151) was intersected with available genotypes. Association to disease was calculated using logistic regression accounting for population structure, and HLA-B27 status was determined with direct polymerase chain reaction genotyping. Results: The cases were found to be 92.3% HLA-B27 positive, with the data set showing >= 80% predictive power to replicate associations, with odds ratios >= 1.6 over a range of allele frequencies (0.1-0.7). Thirty-four markers, representing 23 gene loci, were available for investigation. The replicated variants tagged MICA and IL23R loci (p < 1.47 x 10(-3)), with variable direction of effect noted for gene loci IL1R1 and MST1. Conclusion: The Swedish data set successfully replicated both major histocompatibility complex (MHC) and non-MHC loci, and revealed a different replication pattern compared to discovery data sets. This was possibly due to population demographics, including HLA-B27 frequency and measured comorbidities.
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| 7. |
- Mathioudaki, Argyri, Ph.D student, 1986-, et al.
(författare)
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Replication and fine mapping of ankylosing spondylitis replicated loci in the Swedish population reveal different CCHCR1 protective haplotypes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: The genetics of ankylosing spondylitis (AS) derives mainly from studies performed in large cohorts of British origin. However, within Europe, disease prevalence is higher in Sweden, and so we investigated the reproducibility of known AS susceptibility patterns in a homogeneous Swedish cohort.Methods: The replication power of the Swedish cohort was examined and a set of published SNP associations intersected with genotypes from an existing targeted sequencing study using these individuals (381 controls; 310 AS cases). To elucidate whether replication patterns derived from population subsampling or genetic similarity, allele frequency data from additional British and Swedish control populations were examined for genetic differentiation (FST). Replicated loci were fine mapped to investigate associations in more detail, and signals were dissected with haplotype analysis and functional annotation.Results: The study had 80% power to find variants of strong effect (Odds ratio, OR>2) given a wide range of risk allele frequencies (0.2-3), tagging HLA-B,CCHCR1and IL23R. The replication pattern was not due to European population genetic distance and fine mapping revealed genome-wide repositioned associations in HLA-Band CCHCR1, independent from the published associations (p-value < 2 x10-8, r2 < 0.3). The CCHCR1 locus showed two protective haplotype blocks (B1-1 and B2-1), independent from HLA-B signals (B1-1: r2 = 0.39, B2-2:r2=0.07), where 74% of controls were carrying 2 copies of the protective haplotypes (B1-1 and B2-1: OR=0.3, p-value = 1.2 x 10-45). Interestingly, while both haplotypes span CCHCR1, the effect of each haplotype is likely in cis, with eQTL evidence pointing to the regulation of TCF19(B1-1) and POU5F1(B1-2).Conclusions: Both European populations share key disease loci, but the Swedish cohort revealed fine-scale genetic differences, that may point to gene regulation. This study utilized a different variant resolution, and by doing so demonstrated that smaller populations have the potential to reveal new AS pathogenesis mechanisms and that further study of the Swedish population is warranted.
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| 8. |
- Nordin, Jessika, et al.
(författare)
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Association of Protective HLA-A With HLA-B∗27 Positive Ankylosing Spondylitis
- 2021
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Ingår i: Frontiers in Genetics. - Lausanne, Switzerland : Frontiers Media S.A.. - 1664-8021. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To further elucidate the role of the MHC in ankylosing spondylitis by typing 17 genes, searching for HLA-B∗27 independent associations and assessing the impact of sex on this male biased disease.Methods: High-confidence two-field resolution genotyping was performed on 310 cases and 2196 controls using an n-1 concordance method. Protein-coding variants were called from next-generation sequencing reads using up to four software programs and the consensus result recorded. Logistic regression tests were applied to the dataset as a whole, and also in stratified sets based on sex or HLA-B∗27 status. The amino acids driving association were also examined.Results: Twenty-five HLA protein-coding variants were significantly associated to disease in the population. Three novel protective associations were found in a HLA-B∗27 positive population, HLA-A∗24:02 (OR = 0.4, CI = 0.2–0.7), and HLA-A amino acids Leu95 and Gln156. We identified a key set of seven loci that were common to both sexes, and robust to change in sample size. Stratifying by sex uncovered three novel risk variants restricted to the female population (HLA-DQA1∗04.01, -DQB1∗04:02, -DRB1∗08:01; OR = 2.4–3.1). We also uncovered a set of neutral variants in the female population, which in turn conferred strong effects in the male set, highlighting how population composition can lead to the masking of true associations.Conclusion: Population stratification allowed for a nuanced investigation into the tightly linked MHC region, revealing novel HLA-B∗27 signals as well as replicating previous HLA-B∗27 dependent results. This dissection of signals may help to elucidate sex biased disease predisposition and clinical progression.
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| 9. |
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| 10. |
- Nordmark, Gunnel, et al.
(författare)
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Association of EBF1, FAM167A(C8orf13)-BLK and TNFSF4 gene variants with primary Sjögren's syndrome
- 2011
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 12:2, s. 100-109
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Tidskriftsartikel (refereegranskat)abstract
- We performed a candidate gene association study in 540 patients with primary Sjögren's Syndrome (SS) from Sweden (n=344) and Norway (n=196) and 532 controls (n=319 Swedish, n=213 Norwegian). A total of 1139 single-nucleotide polymorphisms (SNPs) in 84 genes were analyzed. In the meta-analysis of the Swedish and Norwegian cohorts, we found high signals for association between primary SS and SNPs in three gene loci, not previously associated with primary SS. These are the early B-cell factor 1 (EBF1) gene, P=9.9 × 10−5, OR 1.68, the family with sequence similarity 167 member A–B-lymphoid tyrosine kinase (FAM167A–BLK) locus, P=4.7 × 10−4, OR 1.37 and the tumor necrosis factor superfamily (TNFSF4=Ox40L) gene, P=7.4 × 10−4, OR 1.34. We also confirmed the association between primary SS and the IRF5/TNPO3 locus and the STAT4 gene. We found no association between the SNPs in these five genes and the presence of anti-SSA/anti-SSB antibodies. EBF1, BLK and TNFSF4 are all involved in B-cell differentiation and activation, and we conclude that polymorphisms in several susceptibility genes in the immune system contribute to the pathogenesis of primary SS.
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