| 1. |
- Balboni, Imelda, et al.
(författare)
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Brief Report : Interferon-α Induction and Detection of Anti-Ro, Anti-La, Anti-Sm, and Anti-RNP Autoantibodies by Autoantigen Microarray Analysis in Juvenile Dermatomyositis
- 2013
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 65:9, s. 2424-2429
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Tidskriftsartikel (refereegranskat)abstract
- Objective:To evaluate serum interferon- (IFN) activity in the context of autoantibody profiles in patients with juvenile dermatomyositis (JDM). Methods:Sera from 36 patients with JDM were analyzed. Autoantibody profiles were determined by probing microarrays, which were fabricated with approximate to 80 distinct autoantigens, with serum and a Cy3-conjugated secondary antibody. Arrays were scanned and analyzed to determine antigen reactivity. Serum IFN activity was measured using a functional reporter cell assay. Sera were assayed alone or in combination with cellular material released from necrotic U937 cells to stimulate peripheral blood mononuclear cells from healthy donors in vitro, and IFN production in culture was measured by a dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA). Results:Reactivity against at least 1 of 41 autoantigens on the microarray, including Ro 52, Ro 60, La, Sm, and RNP, was observed in 75% of the serum samples from patients with JDM. IFN activity was detected in 7 samples by reporter cell assay. The reporter cell assay showed a significant association of reactivity against Ro, La, Sm, and proliferating cell nuclear antigen with serum IFN activity (P = 0.005). Significance Analysis of Microarrays (SAM) identified increased reactivity against Sm, RNP, Ro 52, U1-C, and Mi-2 in these sera. Sixteen samples induced IFN production as measured by DELFIA, and there was a significant association of reactivity against Ro, La, Sm, and RNP with the induction of IFN by serum and necrotic cell material (P = 0.034). SAM identified increased reactivity against Ro 60 in these sera. Conclusion:These data support the hypothesis that nucleic acid-associated autoantibodies, including the Ro/La and Sm/RNP complexes, may stimulate the production of active IFN in children with JDM.
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| 2. |
- Berggren, Olof, et al.
(författare)
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B lymphocytes enhance the interferon-α production by plasmacytoid dendritic cells
- 2012
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 64:10, s. 3409-3419
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:Type I interferon (IFN) system and B cells are activated in many autoimmune diseases, e.g. systemic lupus erythematosus (SLE). IFNα produced by plasmacytoid dendritic cells (pDC) stimulate several B cell functions, including autoantibody production. However, not much is known how B cells influence the pDC function. We therefore investigated the regulatory effect of B cells on IFNα production by pDC.METHODS:PDC and B cells from healthy blood donor PBMC were stimulated with RNA-containing immune complexes (RNA-IC) consisting of U1 snRNP and IgG from SLE patients, herpes simplex virus (HSV) or oligonucleotide ODN2216, alone or in co-cultures. IFNα, several other cytokines and pDC or B cell-associated surface molecules were analyzed by immunoassays or flow cytometry.RESULTS:B cells enhanced the IFNα production by pDC up to 47-fold, and the effect was most pronounced for pDC stimulated with RNA-IC. Anti-CD31 antibody reduced the RNA-IC-induced IFNα production by 80%, but not when ODN2216 was used as IFN-inducer. Supernatants from ODN2216-stimulated B cells promoted IFNα production by pDC, while supernatants from RNA-IC-stimulated B cells did not.CONCLUSION: Our results reveal a novel B cell function, enhancing the type I IFN production by pDC. Since B cells are activated by type I IFN, this pDC-B cell cross-talk might be of fundamental importance in the etiopathogenesis of SLE, and contribute to a chronic immune activation in SLE and other systemic rheumatic diseases.
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| 3. |
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| 4. |
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| 5. |
- Bolin, Karin, et al.
(författare)
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Association of STAT4 Polymorphism with Severe Renal Insufficiency in Lupus Nephritis
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:12, s. 84450-
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Tidskriftsartikel (refereegranskat)abstract
- Lupus nephritis is a cause of significant morbidity in systemic lupus erythematosus (SLE) and its genetic background has not been completely clarified. The aim of this investigation was to analyze single nucleotide polymorphisms (SNPs) for association with lupus nephritis, its severe form proliferative nephritis and renal outcome, in two Swedish cohorts. Cohort I (n = 567 SLE cases, n = 512 controls) was previously genotyped for 5676 SNPs and cohort II (n = 145 SLE cases, n = 619 controls) was genotyped for SNPs in STAT4, IRF5, TNIP1 and BLK. Case-control and case-only association analyses for patients with lupus nephritis, proliferative nephritis and severe renal insufficiency were performed. In the case-control analysis of cohort I, four highly linked SNPs in STAT4 were associated with lupus nephritis with genome wide significance with p = 3.7x10(-9), OR 2.20 for the best SNP rs11889341. Strong signals of association between IRF5 and an HLA-DR3 SNP marker were also detected in the lupus nephritis case versus healthy control analysis (pless than0.0001). An additional six genes showed an association with lupus nephritis with pless than0.001 (PMS2, TNIP1, CARD11, ITGAM, BLK and IRAK1). In the case-only meta-analysis of the two cohorts, the STAT4 SNP rs7582694 was associated with severe renal insufficiency with p = 1.6x10(-3) and OR 2.22. We conclude that genetic variations in STAT4 predispose to lupus nephritis and a worse outcome with severe renal insufficiency.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Eloranta, Maija-Leena, et al.
(författare)
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Type I interferon system activation and association with disease manifestations in systemic sclerosis
- 2010
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 69:7, s. 1396-1402
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To study the presence of interferogenic autoantibodies in systemic sclerosis (SSc) and their correlation with clinical manifestations, serum levels of interferon alpha (IFNalpha) and chemokines of importance in the disease process. METHODS: Peripheral blood mononuclear cells (PBMCs) or purified plasmacytoid dendritic cells (pDCs) from healthy donors were stimulated with sera from patients with SSc (n=70) or healthy individuals (n=30), together with necrotic or apoptotic cell material. The IFNalpha produced and serum levels of IFNalpha, IFN-inducible protein-10 (IP-10)/chemokine (C-X-C motif) ligand 10, monocyte chemoattractant protein-1 (MCP-1)/(C-C motif) ligand-2 (CCL-2), macrophage inflammatory protein-1alpha (MIP-1alpha)/CCL-3 and RANTES/CCL-5 were measured and correlated with the presence of autoantibodies and clinical manifestations in the patients with SSc. RESULTS: Sera from both diffuse SSc and limited SSc contained interferogenic antibodies, which correlated with the presence of anti-ribonucleoprotein and anti-Sjögren syndrome antigen autoantibodies. The pDCs were responsible for the IFNalpha production which required interaction with FcgammaRII and endocytosis. Increased serum levels of IP-10 were associated with vascular manifestations such as cardiac involvement (p=0.027) and pulmonary arterial hypertension (p=0.036). Increased MCP-1 or IFNalpha serum levels were associated with lung fibrosis (p=0.019 and 0.048, respectively). Digital ulcers including digital loss were associated with increased serum levels of IFNalpha (p=0.029). CONCLUSION: An activated type I IFN system previously seen in several other systemic autoimmune diseases is also present in SSc and may contribute to the vascular pathology and affect the profibrotic process.
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| 11. |
- Enocsson, Helena, et al.
(författare)
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Association of Serum C-Reactive Protein Levels With Lupus Disease Activity in the Absence of Measurable Interferon-α and a C-Reactive Protein Gene Variant
- 2014
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Ingår i: Arthritis & rheumatology (Hoboken, N.J.). - Hoboken, NJ, United States : John Wiley & Sons. - 2326-5191 .- 2326-5205. ; 66:6, s. 1568-1573
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The type I interferon (IFN) system is important in the pathogenesis of systemic lupus erythematosus (SLE). We previously demonstrated an inhibitory effect of IFNα on interleukin 6 (IL-6) induced C-reactive protein (CRP) in vitro, hypothetically explaining the poor correlation between disease activity and CRP levels in SLE. Herein we investigated disease activity, IL-6 and CRP in relation to a CRP gene polymorphism and IFN.Methods: Sera from 155 SLE patients and 100 controls were analyzed for CRP. Patients were genotyped for a CRP single nucleotide polymorphism (rs1205) associated with low CRP levels. Serum IFNα and IL-6 was quantified by immunoassays. Clinical disease activity was assessed by SLE disease activity index 2000 (SLEDAI-2K).Results: CRP levels were increased in SLE patients compared to controls, but were not associated with SLEDAI-2K or IL-6 levels. However, exclusion of patients carrying at least one rs1205 minor allele revealed an association between disease activity and CRP levels (p=0.005). We found a strong association between disease activity and CRP levels (p<0.0005) when patients with measurable IFNα as well as the minor allele of rs1205 where excluded from the analysis. Similarly, when patients with raised IFNα and/or the rs1205 polymorphism were excluded, IL-6 associated with CRP levels.Conclusions: The present study demonstrates that serum IFNα as well as CRP genotype affects the CRP response in SLE patients. Lack of correlation between serum levels of CRP and disease activity could therefore be explained by activation of the type I IFN system and polymorphisms in the CRP gene. © 2014 American College of Rheumatology.
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| 12. |
- Enocsson, Helena, et al.
(författare)
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Serum C-reactive protein (CRP) associates with lupus disease activity in the absence of measurable interferon alpha and a CRP gene variant
- 2014
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Ingår i: Arthritis & rheumatology. - : Wiley. - 2326-5205 .- 2326-5191. ; 66:6, s. 1568-1573
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The type I interferon (IFN) system is important in the pathogenesis of systemic lupus erythematosus (SLE). We previously demonstrated an inhibitory effect of IFNα on interleukin 6 (IL-6) induced C-reactive protein (CRP) in vitro, hypothetically explaining the poor correlation between disease activity and CRP levels in SLE. Herein we investigated disease activity, IL-6 and CRP in relation to a CRP gene polymorphism and IFNαMethods: Sera from 155 SLE patients and 100 controls were analyzed for CRP. Patients were genotyped for a CRP single nucleotide polymorphism (rs1205) associated with low CRP levels. Serum IFNα and IL-6 was quantified by immunoassays. Clinical disease activity was assessed by SLE disease activity index 2000 (SLEDAI-2K).Results: CRP levels were increased in SLE patients compared to controls, but were not associated with SLEDAI-2K or IL-6 levels. However, exclusion of patients carrying at least one rs1205 minor allele revealed an association between disease activity and CRP levels (p=0.005). We found a strong association between disease activity and CRP levels (p<0.0005) when patients with measurable IFNα as well as the minor allele of rs1205 where excluded from the analysis. Similarly, when patients with raised IFNα and/or the rs1205 polymorphism were excluded, IL-6 associated with CRP levels.Conclusions: The present study demonstrates that serum IFNα as well as CRP genotype affects the CRP response in SLE patients. Lack of correlation between serum levels of CRP and disease activity could therefore be explained by activation of the type I IFN system and polymorphisms in the CRP gene.
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| 13. |
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| 14. |
- Feng, Di, et al.
(författare)
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Genetic variants and disease-associated factors contribute to enhanced interferon regulatory factor 5 expression in blood cells of patients with systemic lupus erythematosus
- 2010
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 62:2, s. 562-573
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Genetic variants of the interferon (IFN) regulatory factor 5 gene (IRF5) are associated with susceptibility to systemic lupus erythematosus (SLE). The contribution of these variants to IRF-5 expression in primary blood cells of SLE patients has not been addressed, nor has the role of type I IFNs. The aim of this study was to determine the association between increased IRF-5 expression and the IRF5 risk haplotype in SLE patients. METHODS: IRF-5 transcript and protein levels in 44 Swedish patients with SLE and 16 healthy controls were measured by quantitative real-time polymerase chain reaction, minigene assay, and flow cytometry. Single-nucleotide polymorphisms rs2004640, rs10954213, and rs10488631 and the CGGGG insertion/deletion were genotyped in these patients. Genotypes of these polymorphisms defined both a common risk haplotype and a common protective haplotype. RESULTS: IRF-5 expression and alternative splicing were significantly up-regulated in SLE patients compared with healthy donors. Enhanced transcript and protein levels were associated with the risk haplotype of IRF5; rs10488631 displayed the only significant independent association that correlated with increased transcription from the noncoding first exon 1C. Minigene experiments demonstrated an important role for rs2004640 and the CGGGG insertion/deletion, along with type I IFNs, in regulating IRF5 expression. CONCLUSION: This study provides the first formal proof that IRF-5 expression and alternative splicing are significantly up-regulated in primary blood cells of patients with SLE. Furthermore, the risk haplotype is associated with enhanced IRF-5 transcript and protein expression in patients with SLE.
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| 15. |
- Hagberg, Niklas, et al.
(författare)
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Anti-NKG2A autoantibodies in a patient with systemic lupus erythematosus
- 2013
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 52:10, s. 1818-1823
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo characterize a novel anti-NKG2A autoantibody detected in a patient with SLE during a severe flare, and in a cross-sectional study investigate the occurrence of such autoantibodies in patients with SLE and primary SS (pSS).MethodsSerum or IgG from patients with SLE, pSS and healthy volunteers were assayed for blocking of anti-NKG2A or HLA-E binding to peripheral blood mononuclear cells or CD94/NKG2A- and CD94/NKG2C-transfected Ba/F3 cells. The anti-NKG2A autoantibodies were evaluated for effect on NK cell degranulation in response to HLA-E-transfected K562 cells. IFN-α was determined by an immunoassay and disease activity by the SLEDAI score.ResultsAnti-NKG2A autoantibodies, which blocked binding of HLA-E tetramers to CD94/NKG2A-transfected cells and impaired NKG2A-mediated inhibition of NK cell activation, were observed in a patient with SLE. The presence of anti-NKG2A autoantibodies was associated with high SLE disease activity (SLEDAI score 14 and 16) and increased serum IFN-α. Of 94 SLE, 60 pSS and 30 healthy donor sera, only the index patient serum contained anti-NKG2A autoantibodies.ConclusionThe presence of autoantibodies targeting NKG2A is a rare event, but when such autoantibodies occur they may promote excessive NK cell function. This can contribute to the pathogenesis by increasing the killing of cells and the release of autoantigens. Our findings highlight the possible importance of NK cells in the SLE disease process.
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| 16. |
- Hagberg, Niklas, et al.
(författare)
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IFN-α Production by Plasmacytoid Dendritic Cells Stimulated with RNA-Containing Immune Complexes Is Promoted by NK Cells via MIP-1β and LFA-1
- 2011
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 186:9, s. 5085-5094
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Tidskriftsartikel (refereegranskat)abstract
- Several systemic autoimmune diseases display a prominent IFN signature. This is caused by a continuous IFN-α production by plasmacytoid dendritic cells (pDCs), which are activated by immune complexes (ICs) containing nucleic acid. The IFN-α production by pDCs stimulated with RNA-containing IC (RNA-IC) consisting of anti-RNP autoantibodies and U1 small nuclear ribonucleoprotein particles was recently shown to be inhibited by monocytes, but enhanced by NK cells. The inhibitory effect of monocytes was mediated by TNF-α, PGE2, and reactive oxygen species, but the mechanisms for the NK cell-mediated increase in IFN-α production remained unclear. In this study, we investigated the mechanisms whereby NK cells increase the RNA-IC–induced IFN-α production by pDCs. Furthermore, NK cells from patients with systemic lupus erythematosus (SLE) were evaluated for their capacity to promote IFN-α production. We found that CD56dim NK cells could increase IFN-α production >1000-fold after RNA-IC activation, whereas CD56bright NK cells required costimulation by IL-12 and IL-18 to promote IFN-α production. NK cells produced MIP-1α, MIP-1β, RANTES, IFN-γ, and TNF-α via RNA-IC–mediated FcγRIIIA activation. The IFN-α production in pDCs was promoted by NK cells via MIP-1β secretion and LFA-mediated cell–cell contact. Moreover, NK cells from SLE patients displayed a reduced capacity to promote the RNA-IC–induced IFN-α production, which could be restored by exogenous IL-12 and IL-18. Thus, different molecular mechanisms can mediate the NK cell-dependent increase in IFN-α production by RNA-IC–stimulated pDCs, and our study suggests that the possibility to therapeutically target the NK–pDC axis in IFN-α–driven autoimmune diseases such as SLE should be investigated.
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| 17. |
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| 18. |
- Hagberg, Niklas, et al.
(författare)
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Systemic Lupus Erythematosus Immune Complexes Increase the Expression of SLAM Family Members CD319 (CRACC) and CD229 (LY-9) on Plasmacytoid Dendritic Cells and CD319 on CD56(dim) NK Cells
- 2013
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 191:6, s. 2989-2998
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Tidskriftsartikel (refereegranskat)abstract
- Patients with systemic lupus erythematosus (SLE) display an activated type I IFN system due to unceasing IFN-a release from plasmacytoid dendritic cells (pDCs) stimulated by nucleic acid-containing immune complexes (ICs). NK cells strongly promote the IFN-a production by pDCs; therefore, we investigated surface molecules that could be involved in the pDC-NK cell cross-talk. In human PBMCs stimulated with RNA-containing ICs (RNA-ICs), the expression of the signaling lymphocyte activation molecule (SLAM) family receptors CD319 and CD229 on pDCs and CD319 on CD56(dim) NK cells was selectively increased. Upregulation of CD319 and CD229 on RNA-IC-stimulated pDCs was induced by NK cells or cytokines (e. g., GM-CSF, IL-3). IFN-alpha-producing pDCs displayed a higher expression of SLAM molecules compared with IFN-a 2 pDCs. With regard to signaling downstream of SLAM receptors, pDCs expressed SHIP-1, SHP-1, SHP-2, and CSK but lacked SLAM-associated protein (SAP) and Ewing's sarcoma-activated transcript 2 (EAT2), indicating that these receptors may act as inhibitory receptors on pDCs. Furthermore, pDCs from patients with SLE had decreased expression of CD319 on pDCs and CD229 on CD56 dim NK cells, but RNA-IC stimulation increased CD319 and CD229 expression. In conclusion, this study reveals that the expression of the SLAM receptors CD319 and CD229 is regulated on pDCs and NK cells by lupus ICs and that the expression of these receptors is specifically altered in SLE. These results, together with the observed genetic association between the SLAM locus and SLE, suggest a role for CD319 and CD229 in the SLE disease process.
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| 19. |
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| 20. |
- Hagberg, Niklas, 1977-
(författare)
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The Role of Plasmacytoid Dendritic Cells and Natural Killer Cells in Systemic Lupus Erythematosus
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production, which can eventually lead to immune complex (IC)-mediated organ damage. Due to the stimulation of plasmacytoid dendritic cells (pDC) by nucleic acid-containing ICs (DNA- or RNA-IC), patients with SLE have an ongoing interferon (IFN)-α production. IFN-α induces a general activation of the immune system that may initiate or propagate an autoimmune process if not properly regulated. Previous studies have shown that natural killer (NK) cells potently enhance the IFN-α production by pDCs.In study I, the mechanisms behind the NK cell-mediated increased IFN-α production by RNA-IC-stimulated pDCs were investigated. ICs triggered CD56dim NK cells via FcγRIIIA to the secretion of cytokines (e.g. MIP-1β) that promoted IFN-α production. Additionally, an LFA-1-dependent cell-cell interaction between pDCs and NK cells strongly contributed to the increased production of IFN-α. In study II, the RNA-IC-induced regulation of surface molecules on pDCs and NK cells was investigated. The expression of CD319 and CD229, which are two SLAM family receptors genetically associated with SLE, was induced on pDCs and NK cells by RNA-IC. IFN-α-producing pDCs displayed an increased expression of CD319 and CD229, whereas pDCs from patients with SLE had a decreased expression of CD319. In study III, we serendipitously identified an SLE patient harboring autoantibodies to the NK cell receptor CD94/NKG2A. In study IV, sera from 203 patients with SLE were analyzed for autoantibodies to the CD94/NKG2A, CD94/NKG2C and NKG2D receptors. Seven patients harbored anti-CD94/NKG2A autoantibodies, and two of these patient’s autoantibodies also reacted with CD94/NKG2C. Anti-CD94/NKG2A and anti-CD94/NKG2C autoantibodies both interfered with the HLA-E-mediated regulation of NK cell cytotoxicity, and facilitated the elimination of target cells expressing these receptors. Furthermore, these autoantibodies were found in a group of severely diseased SLE patients and their titers closely followed disease activity.In conclusion, this thesis provides insights to molecular mechanisms whereby NK cells regulate the IFN-α production, it further links the SLAM receptors to SLE, and it describes novel autoantibodies to receptors regulating NK cell cytotoxicity. Together these findings strengthen the assumption that NK cells are involved in the pathogenesis of SLE.
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| 21. |
- Jönsen, Andreas, et al.
(författare)
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Mutations in genes encoding complement inhibitors CD46 and CFH affect the age at nephritis onset in patients with systemic lupus erythematosus
- 2011
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Ingår i: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6362 .- 1478-6354. ; 13, s. R206-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Inherited deficiencies of several complement components strongly predispose to systemic lupus erythematosus (SLE) while deficiencies of complement inhibitors are found in kidney diseases such as atypical hemolytic uremic syndrome (aHUS). METHODS: The exons of complement inhibitor genes: CD46 and CFH (factor H) were fully sequenced using Sanger method in SLE patients with nephritis originating from two cohorts from southern and mid Sweden (n = 196). All identified mutations and polymorphisms were then analyzed in SLE patients without nephritis (n = 326) and healthy controls (n = 523). RESULTS: We found non-synonymous, heterozygous mutations in CFH in 6.1% patients with nephritis in comparison to 4.0% and 5.4% in patients without nephritis and controls, respectively. No associations of SLE or nephritis with common variants in CFH (V62I/Y402H/E936D) were found. Furthermore, we found two non-synonymous heterozygous mutations in CD46 in SLE patients but not in controls. The A353V polymorphism, known to affect function of CD46, was found in 6.6% of nephritis patients vs 4.9% and 6.1% of the non-nephritis SLE patients and controls. The presence of mutations in CD46 and CFH did not predispose to SLE or nephritis but was associated with earlier onset of nephritis. Furthermore, we found weak indications that there is one protective and one risk haplotype predisposing to nephritis composed of several polymorphisms in non-coding regions of CD46, which were previously implicated in aHUS. CONCLUSION: SLE nephritis is not associated with frequent mutations in CFH and CD46 as found in aHUS but these may be modifying factors causing earlier onset of nephritis.
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| 22. |
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| 23. |
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| 24. |
- Leonard, Dag, 1975-
(författare)
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Cardiovascular Disease and Immune Mechanisms in Systemic Lupus Erythematosus
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune, inflammatory disease characterized by autoantibody production and an activated type I interferon system. Cardiovascular disease (CVD) is as a major cause of morbidity and mortality. The aim of this thesis was to identify genetic risk factors for CVD in SLE. The role of T cells in regulation of the interferon-α (IFNα) production by plasmacytoid dendritic cells (pDCs) was also investigated. In paper I, a thicker intima, thinner media and increased intima/media ratio was found in young premenopausal women with SLE compared to healthy controls indicating increased cardiovascular risk. As traditional ultrasound assessment of the common carotid intima-media thickness (CCA-IMT) in SLE has given conflicting results separate measurement of the intima and media can be a useful tool to identify SLE patients at increased risk of CVD. In paper II, an association was demonstrated in SLE between a STAT4 risk allele and ischemic cerebrovascular disease and presence of anti-phospholipid antibodies (aPL). The association remained after adjustment for traditional CVD risk factors. A possible mechanism for this association is that the risk allele leads to increased production of aPL, which promotes thromboembolism. In paper III, a genetic locus in IRF8 was identified to be associated to coronary heart disease (CHD) in SLE. The association remained after adjustment of other CHD risk factors. Patients with the IRF8 risk variant had increased CCA-IMT, more carotid plaques and reduced frequency of circulating B cells. Weaker binding of nuclear protein to the risk allele was demonstrated, suggesting a regulatory function of the IRF8 risk variant. In paper IV, activated T cells were found to strongly enhance the IFNα production by pDC stimulated with RNA-containing immune complexes via GM-CSF and IL-3. Activated SLE T cells enhanced the IFNα production to the same extent as T cells from healthy controls. This finding together with previous observations in SLE of increased levels of GM-CSF and IL-3 suggests that T cells contribute to the activated type I interferon system in SLE. In conclusion, this thesis demonstrates that genetic predisposition is important for CVD in SLE and describes a new role for T cells in the pathogenesis of SLE.
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| 25. |
- Leonard, Dag, et al.
(författare)
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Coronary Heart Disease in Systemic Lupus Erythematosus Is Associated With Interferon Regulatory Factor-8 Gene Variants
- 2013
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Ingår i: Circulation: Cardiovascular Genetics. - : BMJ. - 1942-325X .- 1942-3268. ; 72:Suppl. 3, s. 270-270
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Tidskriftsartikel (refereegranskat)abstract
- Background- Patients with systemic lupus erythematosus have increased morbidity and mortality in coronary heart disease (CHD). We asked whether there was a genetic influence on CHD in systemic lupus erythematosus. Methods and Results- The association between single-nucleotide polymorphisms (SNPs) and CHD in 2 populations of patients with systemic lupus erythematosus was assessed. Patients were genotyped on a custom 12k Illumina Array. The allele frequencies were compared between patients with (n=66) and without (n=509) CHD. We found 61 SNPs with an association (P<0.01) to CHD, with the strongest association for 3 SNPs located in the interferon regulatory factor-8 (IRF8) gene. Comparison of the allele frequencies of these 61 SNPs in patients with (n=27) and without (n=212) CHD in the second study population revealed that 2 SNPs, rs925994 and rs10514610 in IRF8 (linkage disequilibrium, r(2)=0.84), were associated with CHD in both study populations. Meta-analysis of the SNP rs925994 gave an odds ratio of 3.6 (2.1-6.3), P value 1.9x10(-6). The identified IRF8 allele remained as a risk factor for CHD after adjustment for traditional CHD risk factors. The IRF8 risk allele was associated with the presence of carotid plaques (P<0.001) and increased intima-media thickness (P=0.01). By electrophoretic mobility shift assays, we show weaker binding of protein to the risk allele of the highly linked SNP rs11117415, and by flow cytometry, a reduced frequency of circulating B cells was detected in patients with the IRF8 risk allele. Conclusions- There is a considerable genetic component for CHD in systemic lupus erythematosus, with IRF8 as a strong susceptibility locus.
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| 26. |
- Lessard, Christopher J., et al.
(författare)
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Variants at multiple loci implicated in both innate and adaptive immune responses are associated with Sjogren's syndrome
- 2013
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Ingår i: Nature Genetics. - : NATURE PUBLISHING GROUP, 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA. - 1061-4036 .- 1546-1718. ; 45:11, s. 1284-
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Tidskriftsartikel (refereegranskat)abstract
- Sjogrens syndrome is a common autoimmune disease (affecting similar to 0.7% of European Americans) that typically presents as keratoconjunctivitis sicca and xerostomia. Here we report results of a large-scale association study of Sjogrens syndrome. In addition to strong association within the human leukocyte antigen (HLA) region at 6p21 (P-meta = 7.65 x 10(-114)), we establish associations with IRF5-TNPO3 (P-meta = 2.73 x 10(-19)), STAT4 (Pmeta = 6.80 x 10-15), IL12A (P-meta = 1.17 x 10(-10)), FAM167ABLK (P-meta = 4.97 x 10(-10)), DDX6-CXCR5 (P-meta = 1.10 x 10(-8)) and TNIP1 (P-meta = 3.30 x 10(-8)). We also observed suggestive associations (P-meta andlt; 5 x 10(-5)) with variants in 29 other regions, including TNFAIP3, PTTG1, PRDM1, DGKQ, FCGR2A, IRAK1BP1, ITSN2 and PHIP, among others. These results highlight the importance of genes that are involved in both innate and adaptive immunity in Sjogrens syndrome.
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| 27. |
- Ley, Cecilia, et al.
(författare)
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Effects of high mobility group box protein-1, interleukin-1β, and interleukin-6 on cartilage matrix metabolism in three-dimensional equine chondrocyte cultures.
- 2011
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Ingår i: Connective tissue research. - : Informa UK Limited. - 1607-8438 .- 0300-8207. ; 52:4, s. 290-300
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Tidskriftsartikel (refereegranskat)abstract
- The effects of high mobility group box protein (HMGB)-1, interleukin (IL)-1β, and IL-6 on equine articular chondrocytes were investigated, with emphasis on detecting differences between anatomical sites exposed to different loading in vivo, using three-dimensional (3D) cell cultures established with chondrocytes from dorsal radial facet (DRF, highly loaded) and palmar condyle (PC, less loaded) of the third carpal bone (C3). Expression of important genes involved in cartilage metabolism, presence of glycosaminoglycans and cartilage oligomeric matrix protein (COMP) in pellets, and concentrations of matrix metalloproteinase (MMP)-13 and aggrecan epitope CS 846 were evaluated. Compared to controls, IL-1β treatment increased gene expression of versican, matrix-degrading enzymes, and tissue inhibitor of metalloproteinase (TIMP)-1, and decreased aggrecan and collagen type I and type II expression. In addition, IL-1β-treated pellets showed decreased safranin O staining and increased COMP immunostaining and MMP-13 concentrations in culture supernatants. Effects of IL-6 and HMGB-1 on gene expression were variable, although upregulation of Sry-related high-mobility group box 9 (Sox9) was often present and statistically increased in HMGB-1-treated pellets. Response to cytokines rarely differed between DRF and PC pellets. Thus, site-associated cartilage deterioration in equine carpal osteoarthritis (OA) is not explained by topographically different responses to inflammatory mediators. Differences in gene expressions of structural matrix proteins in untreated DRF and PC pellets were noted in the youngest horses, which may indicate differences in the chondrocytes potential to produce matrix in vivo. Overall, a strong catabolic response was induced by IL-1β, whereas slight anabolic effects were induced by IL-6 and HMGB-1.
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| 28. |
- Li, Zhi, et al.
(författare)
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Two rare disease-associated tyk2 variants are catalytically impaired but signaling competent
- 2013
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 190:5, s. 2335-2344
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Tidskriftsartikel (refereegranskat)abstract
- Tyk2 belongs to the Janus protein tyrosine kinase family and is involved in signaling of immunoregulatory cytokines (type I and III IFNs, IL-6, IL-10, and IL-12 families) via its interaction with shared receptor subunits. Depending on the receptor complex, Tyk2 is coactivated with either Jak1 or Jak2, but a detailed molecular characterization of the interplay between the two enzymes is missing. In human populations, the Tyk2 gene presents high levels of genetic diversity with >100 nonsynonymous variants being detected. In this study, we characterized two rare Tyk2 variants, I684S and P1104A, which have been associated with susceptibility to autoimmune disease. Specifically, we measured their in vitro catalytic activity and their ability to mediate Stat activation in fibroblasts and genotyped B cell lines. Both variants were found to be catalytically impaired but rescued signaling in response to IFN-α/β, IL-6, and IL-10. These data, coupled with functional study of an engineered Jak1 P1084A, support a model of nonhierarchical activation of Janus kinases in which one catalytically competent Jak is sufficient for signaling provided that its partner behaves as proper scaffold, even if inactive. Through the analysis of IFN-α and IFN-γ signaling in cells with different Jak1 P1084A levels, we also illustrate a context in which a hypomorphic Jak can hamper signaling in a cytokine-specific manner. Given the multitude of Tyk2-activating cytokines, the cell context-dependent requirement for Tyk2 and the catalytic defect of the two disease-associated variants studied in this paper, we predict that these alleles are functionally significant in complex immune disorders.
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| 29. |
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| 30. |
- Nordlund, Jessica, et al.
(författare)
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Genome-wide signatures of differential DNA methylation in pediatric acute lymphoblastic leukemia
- 2013
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 14:9, s. r105-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Although aberrant DNA methylation has been observed previously in acute lymphoblastic leukemia (ALL), the patterns of differential methylation have not been comprehensively determined in all subtypes of ALL on a genome-wide scale. The relationship between DNA methylation, cytogenetic background, drug resistance and relapse in ALL is poorly understood.RESULTS:We surveyed the DNA methylation levels of 435,941 CpG sites in samples from 764 children at diagnosis of ALL and from 27 children at relapse. This survey uncovered four characteristic methylation signatures. First, compared with control blood cells, the methylomes of ALL cells shared 9,406 predominantly hypermethylated CpG sites, independent of cytogenetic background. Second, each cytogenetic subtype of ALL displayed a unique set of hyper- and hypomethylated CpG sites. The CpG sites that constituted these two signatures differed in their functional genomic enrichment to regions with marks of active or repressed chromatin. Third, we identified subtype-specific differential methylation in promoter and enhancer regions that were strongly correlated with gene expression. Fourth, a set of 6,612 CpG sites was predominantly hypermethylated in ALL cells at relapse, compared with matched samples at diagnosis. Analysis of relapse-free survival identified CpG sites with subtype-specific differential methylation that divided the patients into different risk groups, depending on their methylation status.CONCLUSIONS:Our results suggest an important biological role for DNA methylation in the differences between ALL subtypes and in their clinical outcome after treatment.
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| 31. |
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| 32. |
- 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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| 33. |
- Nordmark, Gunnel, et al.
(författare)
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Association of Genes in the NF-κB Pathway with Antibody-Positive Primary Sjögren's Syndrome
- 2013
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Ingår i: Scandinavian Journal of Immunology. - : Wiley-Blackwell. - 0300-9475 .- 1365-3083. ; 78:5, s. 447-454
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Tidskriftsartikel (refereegranskat)abstract
- Primary Sjogrens syndrome (SS) is a systemic autoimmune inflammatory disease characterized by focal lymphocytic infiltrates in the lachrymal and salivary glands and autoantibodies against the SSA/Ro and SSB/La antigens. Experimental studies have shown an activation of NF-B in primary SS. NF-B activation results in inflammation and autoimmunity and is regulated by inhibitory and activating proteins. Genetic studies have shown an association between multiple autoimmune diseases and TNFAIP3 (A20) and TNIP1 (ABIN1), both repressors of NF-B and of IKBKE (IKK epsilon), which is an NF-B activator. The aim of this study was to analyse single nucleotide polymorphisms (SNPs) in the IKBKE, NFKB1, TNIP1 and TNFAIP3 genes for association with primary SS. A total of 12 SNPs were genotyped in 1105 patients from Scandinavia (Sweden and Norway, n=684) and the UK (n=421) and 4460 controls (Scandinavia, n=1662, UK, n=2798). When patients were stratified for the presence of anti-SSA and/or anti-SSB antibodies (n=868), case-control meta-analysis found an association between antibody-positive primary SS and two SNPs in TNIP1 (P=3.4x10(-5), OR=1.33, 95%CI: 1.16-1.52 for rs3792783 and P=1.3x10(-3), OR=1.21, 95%CI: 1.08-1.36 for rs7708392). A TNIP1 risk haplotype was associated with antibody-positive primary SS (P=5.7x10(-3), OR=1.47, 95%CI: 1.12-1.92). There were no significant associations with IKBKE, NFKB1 or TNFAIP3 in the meta-analysis of the Scandinavian and UK cohorts. We conclude that polymorphisms in TNIP1 are associated with antibody-positive primary SS.
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| 34. |
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| 35. |
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| 36. |
- Nordmark, Gunnel, et al.
(författare)
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Primary Sjögren's syndrome and the type I interferon system
- 2012
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Ingår i: Current Pharmaceutical Biotechnology. - 1389-2010 .- 1873-4316. ; 13:10, s. 2054-2062
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Forskningsöversikt (refereegranskat)abstract
- Patients with primary Sjögren's syndrome (pSS) have an activated type I interferon (IFN) system that contribute to the etiopathogenesis and clinical manifestations of the disease. The type I IFN system consists of the stimuli for type I IFN production, the receptors, cells and transcription factors involved in the synthesis of type I IFNs, the type I IFN-receptor and the effects on target cells. Increased type I IFN activity has been demonstrated in sera from patients with pSS and IFN-α, the main type I IFN, has been detected in the minor salivary glands. Gene expression profiling of peripheral blood mononuclear cells (PBMCs) and minor salivary glands from pSS patients display an up-regulation of type I IFN-induced genes, an "IFN signature". The professional IFN-α producing plasmacytoid dendritic cell (pDC) shows a reduced frequency in the peripheral blood, but has been detected in the salivary glands, possibly due to tissue recruitment. Polymorphisms in the interferon regulatory factor 5 (IRF5) and signal transducer and activator of transcription 4 (STAT4) genes in the type I IFN system, are associated with increased risk for pSS. A postulated disease model is that an initial viral infection induces type I IFN production in the salivary glands with subsequent activation of the adaptive immune system resulting in the production of autoantibodies against the RNA-binding proteins SSA/SSB/RNP. Interferogenic immune complexes are formed, which trigger the pDCs to an ongoing type I IFN production, which sustain the disease process. Potential therapeutic targets can be identified within the type I IFN system.
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| 37. |
- Rusakiewicz, Sylvie, et al.
(författare)
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NCR3/NKp30 contributes to pathogenesis in primary Sjogren's syndrome.
- 2013
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Ingår i: Science translational medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6242 .- 1946-6234. ; 5:195
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Tidskriftsartikel (refereegranskat)abstract
- Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by a lymphocytic exocrinopathy. However, patients often have evidence of systemic autoimmunity, and they are at markedly increased risk for the development of non- Hodgkin's lymphoma. Similar to other autoimmune disorders, a strong interferon (IFN) signature is present among subsets of pSS patients, although the precise etiology remains uncertain. NCR3/NKp30 is a natural killer (NK)-specific activating receptor regulating the cross talk between NK and dendritic cells and type II IFN secretion. We performed a case-control study of genetic polymorphisms of the NCR3/NKp30 gene and found that rs11575837 (G>A) residing in the promoter was associated with reduced gene transcription and function as well as protection to pSS. We also demonstrated that circulating levels of NCR3/NKp30 were significantly increased among pSS patients compared with controls and correlated with higher NCR3/NKp30 but not CD16-dependent IFN-γ secretion by NK cells. Excess accumulation of NK cells in minor salivary glands correlated with the severity of the exocrinopathy. B7H6, the ligand of NKp30, was expressed by salivary epithelial cells. These findings suggest that NK cells may promote an NKp30-dependent inflammatory state in salivary glands and that blockade of the B7H6/NKp30 axis could be clinically relevant in pSS.
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| 38. |
- Rönnblom, Lars, et al.
(författare)
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The interferon signature in autoimmune diseases
- 2013
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Ingår i: Current Opinion in Rheumatology. - 1040-8711 .- 1531-6963. ; 25:2, s. 248-253
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Forskningsöversikt (refereegranskat)abstract
- PURPOSE OF REVIEW:An increased expression of type I interferon (IFN) regulated genes (an IFN signature) has been reported in blood and tissue cells from patients with SLE and other autoimmune diseases. We review the possible mechanisms behind the IFN signature as well as clinical and therapeutic consequences of this observation.RECENT FINDINGS:Autoantigens from dying cells trigger plasmacytoid dendritic cells to a continuous synthesis of type I IFN, which is promoted by natural killer (NK) cells and B cells. A growing number of genes connected to type I IFN production and response associates with an increased susceptibility to autoimmunity. Besides type I IFN, type III IFN (IFN-λ) may contribute to the IFN signature. In SLE and primary Sjögren's syndrome, a prominent IFN signature is connected to an active disease, whereas in rheumatoid arthritis the IFN signature defines a disease subset with poor clinical outcome and treatment failure to B-cell depleting therapy. Several therapies aiming to inhibit the IFN signature are in clinical trials and early data suggest clinical benefits without major safety problems.SUMMARY:The observed IFN signature in several autoimmune diseases is a biomarker of active disease and is investigated as a tool when selecting treatment for individual patients.
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| 39. |
- Rönnblom, Lars, et al.
(författare)
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The type I interferon system in the development of lupus
- 2011
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Ingår i: Seminars in Immunology. - : Elsevier BV. - 1044-5323 .- 1096-3618. ; 23:2, s. 113-121
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Forskningsöversikt (refereegranskat)abstract
- The type I interferon (IFN) system induces inhibition of viral replication, but can also activate the innate and adaptive immune system. An important role of the type I IFN system in autoimmune diseases, including lupus, is suggested by the observation that these disorders display a prominent over-expression of type I IFN regulated genes. The development of autoimmune diseases in some individuals treated with IFN-α directly supports a pivotal role for this cytokine in breaking tolerance and inducing autoimmune reactions. A genetic setup that promotes type I IFN production and/or response and the presence of endogenous inducers of IFN-α production have been described in patients with lupus. Several known environmental risk factors for development of lupus or disease flares may contribute to the ongoing type I IFN production. In the present review we will describe the possible role of the type I IFN system in the lupus disease process. The possible connection between the type I IFN system and some environmental and genetic risk factors for lupus is also discussed.
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| 40. |
- Sandling, Johanna K., et al.
(författare)
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A candidate gene study of the type I interferon pathway implicates IKBKE and IL8 as risk loci for SLE
- 2011
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 19:4, s. 479-484
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Tidskriftsartikel (refereegranskat)abstract
- Systemic Lupus Erythematosus (SLE) is a systemic autoimmune disease in which the type I interferon pathway has a crucial role. We have previously shown that three genes in this pathway, IRF5, TYK2 and STAT4, are strongly associated with risk for SLE. Here, we investigated 78 genes involved in the type I interferon pathway to identify additional SLE susceptibility loci. First, we genotyped 896 single-nucleotide polymorphisms in these 78 genes and 14 other candidate genes in 482 Swedish SLE patients and 536 controls. Genes with P<0.01 in the initial screen were then followed up in 344 additional Swedish patients and 1299 controls. SNPs in the IKBKE, TANK, STAT1, IL8 and TRAF6 genes gave nominal signals of association with SLE in this extended Swedish cohort. To replicate these findings we extracted data from a genomewide association study on SLE performed in a US cohort. Combined analysis of the Swedish and US data, comprising a total of 2136 cases and 9694 controls, implicates IKBKE and IL8 as SLE susceptibility loci (P(meta)=0.00010 and P(meta)=0.00040, respectively). STAT1 was also associated with SLE in this cohort (P(meta)=3.3 × 10(-5)), but this association signal appears to be dependent of that previously reported for the neighbouring STAT4 gene. Our study suggests additional genes from the type I interferon system in SLE, and highlights genes in this pathway for further functional analysis.
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| 41. |
- Stone, Rivka C, et al.
(författare)
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Interferon regulatory factor 5 activation in monocytes of systemic lupus erythematosus patients is triggered by circulating autoantigens independent of type I interferons
- 2012
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 64:3, s. 788-798
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Genetic variants of interferon regulatory factor 5 (IRF-5) are associated with susceptibility to systemic lupus erythematosus (SLE). IRF-5 regulates the expression of proinflammatory cytokines and type I interferons (IFNs) believed to be involved in the pathogenesis of SLE. The aim of this study was to determine the activation status of IRF-5 by assessing its nuclear localization in the immune cells of SLE patients and healthy donors, and to identify SLE-associated triggers of IRF-5 activation. Methods: IRF-5 nuclear localization in subpopulations of peripheral blood mononuclear cells from 14 genotyped SLE patients and 11 healthy controls was assessed using imaging flow cytometry. The activation and function of IRF-5 were examined after ex vivo stimulation of healthy donor monocytes with SLE serum or components of SLE serum. Cellular localization was determined by ImageStream flow cytometry, and cytokine expression was analyzed by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Results: IRF-5 was activated in a cell type–specific manner; monocytes from SLE patients had constitutively elevated levels of nuclear IRF-5, as compared to natural killer cells and T cells. SLE serum was identified as a trigger for IRF-5 nuclear accumulation; however, neither IFNα nor SLE immune complexes could induce nuclear localization. Instead, autoantigens composed of apoptotic/necrotic material triggered IRF-5 nuclear accumulation in monocytes. Production of the cytokines IFNα, tumor necrosis factor α, and interleukin-6 in monocytes stimulated with SLE serum or autoantigens was distinct, yet showed a correlation with the kinetics of IRF-5 nuclear localization. Conclusion: This study provides the first formal proof that IRF-5 activation is altered in the monocytes of SLE patients, which can be attributed, in part, to the SLE blood environment.
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| 42. |
- Stone, R. C., et al.
(författare)
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RNA-Seq for Enrichment and Analysis of IRF5 Transcript Expression in SLE
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:1, s. 54487-
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Tidskriftsartikel (refereegranskat)abstract
- Polymorphisms in the interferon regulatory factor 5 (IRF5) gene have been consistently replicated and shown to confer risk for or protection from the development of systemic lupus erythematosus (SLE). IRF5 expression is significantly upregulated in SLE patients and upregulation associates with IRF5-SLE risk haplotypes. IRF5 alternative splicing has also been shown to be elevated in SLE patients. Given that human IRF5 exists as multiple alternatively spliced transcripts with distinct function(s), it is important to determine whether the IRF5 transcript profile expressed in healthy donor immune cells is different from that expressed in SLE patients. Moreover, it is not currently known whether an IRF5-SLE risk haplotype defines the profile of IRF5 transcripts expressed. Using standard molecular cloning techniques, we identified and isolated 14 new differentially spliced IRF5 transcript variants from purified monocytes of healthy donors and SLE patients to generate an IRF5 variant transcriptome. Next-generation sequencing was then used to perform in-depth and quantitative analysis of full-length IRF5 transcript expression in primary immune cells of SLE patients and healthy donors by next-generation sequencing. Evidence for additional alternatively spliced transcripts was obtained from de novo junction discovery. Data from these studies support the overall complexity of IRF5 alternative splicing in SLE. Results from next-generation sequencing correlated with cloning and gave similar abundance rankings in SLE patients thus supporting the use of this new technology for in-depth single gene transcript profiling. Results from this study provide the first proof that 1) SLE patients express an IRF5 transcript signature that is distinct from healthy donors, 2) an IRF5-SLE risk haplotype defines the top four most abundant IRF5 transcripts expressed in SLE patients, and 3) an IRF5 transcript signature enables clustering of SLE patients with the H2 risk haplotype.
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| 43. |
- Wang, Chuan, et al.
(författare)
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Contribution of IKBKE and IFIH1 gene variants to SLE susceptibility
- 2013
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 14:4, s. 217-222
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Tidskriftsartikel (refereegranskat)abstract
- The type I interferon system genes IKBKE and IFIH1 are associated with the risk of systemic lupus erythematosus (SLE). To identify the sequence variants that are able to account for the disease association, we resequenced the genes IKBKE and IFIH1. Eighty-six single-nucleotide variants (SNVs) with potentially functional effect or differences in allele frequencies between patients and controls determined by sequencing were further genotyped in 1140 SLE patients and 2060 controls. In addition, 108 imputed sequence variants in IKBKE and IFIH1 were included in the association analysis. Ten IKBKE SNVs and three IFIH1 SNVs were associated with SLE. The SNVs rs1539241 and rs12142086 tagged two independent association signals in IKBKE, and the haplotype carrying their risk alleles showed an odds ratio of 1.68 (P-value=1.0 × 10−5). The risk allele of rs12142086 affects the binding of splicing factor 1 in vitro and could thus influence its transcriptional regulatory function. Two independent association signals were also detected in IFIH1, which were tagged by a low-frequency SNV rs78456138 and a missense SNV rs3747517. Their joint effect is protective against SLE (odds ratio=0.56; P-value=6.6 × 10−3). In conclusion, we have identified new SLE-associated sequence variants in IKBKE and IFIH1, and proposed functional hypotheses for the association signals.
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| 44. |
- Wang, Chuan, et al.
(författare)
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Genes identified in Asian SLE GWASs are also associated with SLE in Caucasian populations
- 2013
-
Ingår i: European Journal of Human Genetics. - : Nature Publishing Group: Open Access Hybrid Model Option B. - 1018-4813 .- 1476-5438. ; 21:9, s. 994-999
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Tidskriftsartikel (refereegranskat)abstract
- Recent genome-wide association studies (GWASs) conducted in Asian populations have identified novel risk loci for systemic lupus erythematosus (SLE). Here, we genotyped 10 single-nucleotide polymorphisms (SNPs) in eight such loci and investigated their disease associations in three independent Caucasian SLE case–control cohorts recruited from Sweden, Finland and the United States. The disease associations of the SNPs in ETS1, IKZF1, LRRC18-WDFY4, RASGRP3, SLC15A4, TNIP1 and 16p11.2 were replicated, whereas no solid evidence of association was observed for the 7q11.23 locus in the Caucasian cohorts. SLC15A4 was significantly associated with renal involvement in SLE. The association of TNIP1 was more pronounced in SLE patients with renal and immunological disorder, which is corroborated by two previous studies in Asian cohorts. The effects of all the associated SNPs, either conferring risk for or being protective against SLE, were in the same direction in Caucasians and Asians. The magnitudes of the allelic effects for most of the SNPs were also comparable across different ethnic groups. On the contrary, remarkable differences in allele frequencies between Caucasian and Asian populations were observed for all associated SNPs. In conclusion, most of the novel SLE risk loci identified by GWASs in Asian populations were also associated with SLE in Caucasian populations. We observed both similarities and differences with respect to the effect sizes and risk allele frequencies across ethnicities.
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| 45. |
- Wang, Chuan, et al.
(författare)
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Genome-wide profiling of target genes for the systemic lupus erythematosus-associated transcription factors IRF5 and STAT4
- 2013
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 72:1, s. 96-103
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:The transcription factors interferon regulatory factor 5 (IRF5) and signal transducer and activator of transcription 4 (STAT4) are encoded by two of the strongest susceptibility genes for systemic lupus erythematosus (SLE).OBJECTIVE:To investigate the target genes and functional roles of IRF5 and STAT4 in human peripheral blood mononuclear cells (PBMCs).METHODS: Chromatin immunoprecipitation-sequencing (ChIP-seq) was performed in PBMCs stimulated to activate IRF5 and STAT4. The expression of the target genes of IRF5 and STAT4 was investigated in a publicly available dataset generated from PBMCs from patients with SLE and healthy controls. The genomic regions bound by the transcription complexes mediated by IRF5 and STAT4 were examined for transcription factor binding motifs and SLE-associated sequence variants.RESULTS: More than 7000 target genes for IRF5 and STAT4 were identified in stimulated PBMCs. These genes were enriched to functional pathways in the type I interferon system, and have key roles in the inflammatory response. The expression patterns of the target genes were characteristic for patients with SLE. The transcription factors high mobility group-I/Y, specificity protein 1, and paired box 4 may function cooperatively with IRF5 and STAT4 in transcriptional regulation. Eight of the target regions for IRF5 and STAT4 contain SLE-associated sequence variants.CONCLUSIONS:By participating in transcription complex with other co-factors, IRF5 and STAT4 harbour the potential of regulating a large number of target genes, which may contribute to their strong association with SLE.
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| 46. |
- Åhlin, Erik, 1980-, et al.
(författare)
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Autoantibodies associated with RNA are more enriched than anti-dsDNA antibodies in circulating immune complexes in SLE
- 2012
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Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 21:6, s. 586-595
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Tidskriftsartikel (refereegranskat)abstract
- To what extent different autoantibodies accumulate in systemic lupus erythematosus (SLE) immune complexes (ICs), and whether such accumulation is associated with disease activity has been investigated. ICs were isolated from SLE sera by both polyethylene glycol (PEG) precipitation and C1q-binding. Autoantibody specificities were determined using a lineblot assay quantified by densitometry. To compare the relative levels of autoantibodies, levels were normalized to the total levels of IgG measured by ELISA in sera and parallel ICs. Samples were investigated both in a cross-sectional design as well as in a paired design with samples obtained during both active and inactive SLE. All investigated autoantibody specificities except anti-dsDNA were enriched in circulating ICs as compared with parallel sera. The group of antibodies against RNA-associated antigens (anti-RNP/Sm, anti-Sm, anti-SSA/Ro60, anti-SSA/Ro52, anti-SSB/La) all exhibited higher median enrichment than the DNA-associated (anti-dsDNA, anti-histones, anti-nucleosomes) or cytoplasmic (anti-ribosomal P) antigens. In particular autoantibodies against RNP/Sm and SSA/Ro52 had the highest degree of enrichment in SLE PEG precipitates. These findings were corroborated by analysis of autoantibody content in C1q-bound ICs. There was no difference in degree of IC accumulation of the investigated autoantibodies during active and inactive SLE. Our findings demonstrate a difference in enrichment between autoantibodies against RNA- and DNA-associated autoantigens in isolated SLE IC, suggesting that the RNA-associated autoantibodies are more prone to form circulating ICs in SLE, in contrast to antibodies against DNA-associated autoantigens such as dsDNA. These finding have implications in understanding mechanisms of differential autoantibody accumulation in target organs in SLE.
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