| 1. |
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| 2. |
- Ahlgren, Kerstin, M., et al.
(författare)
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Type I Interferon signature in Nova Scotia duck tolling retriever dogs with steroid responsive meningitis-arteritis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: Dogs of the breed Nova Scotia duck tolling retriever (NSDTR) are prone to develop a disease complex in some aspects resembling human systemic lupus erythematosus (SLE). Peripheral blood mononuclear cells (PBMCs) from human SLE patients have an increased mRNA expression type I interferon (IFN) regulated genes. However, it is unknown whether diseased dogs also display the typical type I IFN signature. Methods: To test canine sera for their capacity to induce type I IFN response Mardin-Darby canine kidney (MDCK) cells were cultured with sera from healthy dogs (n=25), immune-mediated rheumatic disease (IMRD) dogs with anti-nuclear antibodies (ANA+) (n=30) or dogs with steroid responsive meningitis-arteritis (SRMA) (n=25). mRNA expression of the genes MX1, IFIT1 and CXCL10 was measured by quantitative Real Time PCR. Results: A highly significant (p=0.0009) increase in mRNA expression of the type I IFN responsive gene MX1 was detected in cells stimulated by sera from dogs with SRMA, but not from IMRD ANA+ dogs. Expression of IFIT1 was twice as high in cells stimulated by sera from dogs with SRMA compared to both healthy dogs and ANA+ dogs. The mean expression of CXCL10 was nearly ten times higher in cells stimulated by sera from SRMA dogs than by ANA+ dogs and four times higher compared to cells stimulated by control dogs. Conclusion: Presence of type I IFN in sera from diseased NSDTR dogs was found in this study. This implies that this canine model can be used for identification of pathways of importance for autoimmune disorders in humans and for testing of novel therapeutic approaches. Our results can also be a step on the way towards personalized drugs in these dogs.
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| 3. |
- Almlöf, Jonas Carlsson, et al.
(författare)
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Whole-genome sequencing identifies complex contributions to genetic risk by variants in genes causing monogenic systemic lupus erythematosus
- 2019
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Ingår i: Human Genetics. - : SPRINGER. - 0340-6717 .- 1432-1203. ; 138:2, s. 141-150
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Tidskriftsartikel (refereegranskat)abstract
- Systemic lupus erythematosus (SLE, OMIM 152700) is a systemic autoimmune disease with a complex etiology. The mode of inheritance of the genetic risk beyond familial SLE cases is currently unknown. Additionally, the contribution of heterozygous variants in genes known to cause monogenic SLE is not fully understood. Whole-genome sequencing of DNA samples from 71 Swedish patients with SLE and their healthy biological parents was performed to investigate the general genetic risk of SLE using known SLE GWAS risk loci identified using the ImmunoChip, variants in genes associated to monogenic SLE, and the mode of inheritance of SLE risk alleles in these families. A random forest model for predicting genetic risk for SLE showed that the SLE risk variants were mainly inherited from one of the parents. In the 71 patients, we detected a significant enrichment of ultra-rare (0.1%) missense and nonsense mutations in 22 genes known to cause monogenic forms of SLE. We identified one previously reported homozygous nonsense mutation in the C1QC (Complement C1q C Chain) gene, which explains the immunodeficiency and severe SLE phenotype of that patient. We also identified seven ultra-rare, coding heterozygous variants in five genes (C1S, DNASE1L3, DNASE1, IFIH1, and RNASEH2A) involved in monogenic SLE. Our findings indicate a complex contribution to the overall genetic risk of SLE by rare variants in genes associated with monogenic forms of SLE. The rare variants were inherited from the other parent than the one who passed on the more common risk variants leading to an increased genetic burden for SLE in the child. Higher frequency SLE risk variants are mostly passed from one of the parents to the offspring affected with SLE. In contrast, the other parent, in seven cases, contributed heterozygous rare variants in genes associated with monogenic forms of SLE, suggesting a larger impact of rare variants in SLE than hitherto reported.
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| 4. |
- 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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| 5. |
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| 6. |
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| 7. |
- Berggren, Olof, et al.
(författare)
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Activation of plasmacytoid dendritic cells and B cells with two structurally different Toll-like receptor 7 agonists
- 2020
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 91:6
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic Toll-like receptor (TLR) 7 agonists have been suggested as immune modulators in a range of conditions. In contrast, self-derived TLR7 activators, such as RNA-containing immune complexes (RNA-IC), can contribute to autoimmune diseases due to endogenous immune activation. The exact difference in immune cell response between synthetic and endogenous TLR7 triggers is only partly known. An understanding of these differences could aid in the development of new therapeutic agents and provide insights into autoimmune disease mechanisms. We therefore compared the stimulatory capacity of two TLR7 agonists, RNA-IC and a synthetic small molecule DSR-6434, on blood leucocytes, plasmacytoid dendritic cells (pDCs) and B cells from healthy individuals. IFN-α, IL-6, IL-8 and TNF levels were measured by immunoassays, and gene expression in pDCs was analysed by an expression array. DSR-6434 triggered 20-fold lower levels of IFN-α by pDCs, but higher production of IL-6, IL-8 and TNF, compared to RNA-IC. Furthermore, IFN-α and TNF production were increased with exogenous IFN-α2b priming, whereas IL-8 synthesis by B cells was reduced for both stimuli. Cocultivation of pDCs and B cells increased the RNA-IC-stimulated IFN-α and TNF levels, while only IL-6 production was enhanced in the DSR-6434-stimulated cocultures. When comparing pDCs stimulated with RNA-IC and DSR-6434, twelve genes were differentially expressed (log2 fold change >2, adjusted P-value <.05). In conclusion, RNA-IC, which mimics an endogenous TLR7 stimulator, and the synthetic TLR7 agonist DSR-6434 trigger distinct inflammatory profiles in immune cells. This demonstrates the importance of using relevant stimuli when targeting the TLR7 pathway for therapeutic purposes.
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| 8. |
- 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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| 9. |
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| 10. |
- Berggren, Olof, et al.
(författare)
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IFN-α production by plasmacytoid dendritic cell associations with polymorphisms in gene loci related to autoimmune and inflammatory diseases
- 2015
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 24:12, s. 3571-3581
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Tidskriftsartikel (refereegranskat)abstract
- The type I interferon (IFN) system is persistently activated in systemic lupus erythematosus (SLE) and many other systemic autoimmune diseases. Studies have shown an association between SLE and several gene variants within the type I IFN system. We investigated whether single nucleotide polymorphisms (SNPs) associated with SLE and other autoimmune diseases affect the IFN-α production in healthy individuals. Plasmacytoid dendritic cells (pDCs), B and NK cells were isolated from peripheral blood of healthy individuals and stimulated with RNA-containing immune complexes (IC), herpes simplex virus (HSV) or the oligonucleotide ODN2216. IFN-α production by pDCs alone or in cocultures with B or NK cells was measured by an immunoassay. All donors were genotyped with the 200K ImmunoChip and a 5bp CGGGG length polymorphism in the IFN regulatory factor 5 gene (IRF5) was genotyped by PCR. We found associations between IFN-α production and 18-86 SNPs (p ≤ 0.001), depending on the combination of the stimulated cell types. However, only three of these associated SNPs were shared between the cell type combinations. Several SNPs showed novel associations to the type I IFN system among all the associated SNPs, while some loci have been described earlier for their association with SLE. Furthermore, we found that the SLE-risk variant of the IRF5 CGGGG-indel was associated with lower IFN-α production. We conclude that the genetic variants affecting the IFN-α production highlight the intricate regulation of the type I IFN system and the importance of understanding the mechanisms behind the dysregulated type I IFN system in SLE.
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| 11. |
- Berggren, Olof, et al.
(författare)
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Plasmacytoid dendritic cells and RNA-containing immune complexes drive expansion of peripheral B cell subsets with an SLE-like phenotype
- 2017
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- Background Hyperactive B cells and a continuous interferon (IFN)-alpha production by plasmacytoid dendritic cells (pDCs) play a key role in systemic lupus erythematosus (SLE). We asked whether the interaction between B cells and pDCs stimulated with RNA-containing immune complexes affects peripheral B cell subsets. Methods B cells and pDCs were isolated from blood of healthy individuals and stimulated with immune complexes consisting of SLE-IgG and U1snRNP (RNA-IC). Expression of cell surface molecules as well as IL-6 and IL-10 production were determined by flow cytometry and immunoassays. Gene expression profiles were determined by a NanoString nCounter expression array. Results We found a remarkable increase of double negative CD27-IgD-B cells, from 7% within fresh CD19+B cells to 37% in the RNA-IC-stimulated co-cultures of B cells and pDCs, comparable to the frequency of double negative B cells in SLE patients. Gene expression analysis of the double negative CD27-IgD -and the CD27 + IgD-memory B cells revealed that twenty-one genes were differentially expressed between the two B cell subsets (>= 2-fold, p< 0.001). The, IL21R, IL4R, CCL4, CCL3, CD83 and the IKAROS Family Zinc Finger 2 (IKZ2) showed higher expression in the double negative CD27-IgD-B cells. Conclusion The interactions between B cells and pDCs together with RNA-containing IC led to an expansion of B cells with similar phenotype as seen in SLE, suggesting that the pDC-B cell crosstalk contributes to the autoimmune feed-forward loop in SLE.
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| 12. |
- Berggren, Olof
(författare)
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Regulation of Type I Interferon Production in Plasmacytoid Dendritic Cells : Effect of Genetic Factors and Interactions with NK Cells and B Cells
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The type I interferon (IFN) system plays a central role in the etiopathogenesis of many autoimmune diseases, e.g. systemic lupus erythematosus (SLE). Activation of the type I IFN system in SLE is promoted by endogenous nucleic acid-containing immune complexes (ICs) which stimulate plasmacytoid dendritic cells (pDCs). This thesis focuses on the regulation of IFN-α production in pDCs, by interactions with B cells and natural killer (NK) cells, and by genetic factors.In Study I, RNA-IC-stimulated CD56dim NK cells were found to be activated via FcγRIIIa and enhanced the IFN-α production by pDCs. The enhancing effect of the NK cells was mediated via both soluble factors, such as the cytokine MIP-1β, and in a cell-cell contact mediated manner via the adhesion molecule LFA-1. In Study II, B cells enhanced the IFN-α production by pDCs via cell-cell contact or soluble factors, depending on the stimuli. The cell-cell contact-mediated enhancement, when the cells were stimulated with RNA-IC, was abolished by blocking the cell adhesion molecule CD31. B cells stimulated with the oligonucleotide ODN2216 enhanced the IFN-α production via soluble factors. In Study III, gene variants related to autoimmune or inflammatory diseases were analyzed for the association to the IFN-α production by pDCs, alone or in coculture with NK or B cells. Depending on cell combination, 18-86 SNPs (p < 0.001) were associated with the IFN-α production. Several of the SNPs showed novel associations to the type I IFN system, while some loci have been described earlier for their association with SLE, e.g. IL10 and PXK. In Study IV, several B cell populations were affected by cocultivation with pDCs and stimulation with RNA-IC. The frequency of CD24hiCD38hi B cells of regulatory character was increased in the pDC-B cell cocultures. However, RNA-IC-stimulation only induced modest levels of IL-10. A remarkably increased frequency of double negative CD27-IgD- B cells was found in the RNA-IC-stimulated cocultures of pDCs and B cells.In conclusion, the findings in the present thesis reveal novel mechanisms behind the regulation of the type I IFN system which could be important targets in autoimmune diseases with constantly activated pDCs.
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| 13. |
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| 14. |
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| 15. |
- Blomberg, Stina, et al.
(författare)
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Expression of the markers BDCA-2 and BDCA-4 and production of interferon-alpha by plasmacytoid dendritic cells in systemic lupus erythematosus
- 2003
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 48:9, s. 2524-32
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the expression of blood dendritic cell antigen 2 (BDCA-2) and BDCA-4 molecules by plasmacytoid dendritic cells (PDCs) in the blood of patients with systemic lupus erythematosus (SLE), and to study PDC production of interferon-alpha (IFN alpha) and its inhibition by anti-BDCA-2 and anti-BDCA-4 antibodies. METHODS: Peripheral blood mononuclear cells (PBMCs) from SLE patients (SLE PBMCs) and from healthy controls were induced to produce IFN alpha in vitro by SLE serum containing an endogenous IFN alpha-inducing factor (SLE-IIF) or by herpes simplex virus type 1 (HSV-1). The frequencies and numbers of BDCA-2-, BDCA-3-, and BDCA-4-expressing cells were analyzed by flow cytometry, and the effects of anti-BDCA-2 and anti-BDCA-4 monoclonal antibodies (mAb) on IFN alpha production were investigated. RESULTS: IFN alpha production by SLE PBMCs induced by SLE-IIF or HSV-1 was decreased compared with that of healthy control PBMCs (P = 0.002 and P = 0.0007, respectively). The proportions of BDCA-2- and BDCA-3-expressing cells in SLE PBMCs were reduced compared with those in PBMCs from healthy controls (P = 0.01 and P = 0.004, respectively). IFN alpha producers in culture, especially among SLE PBMCs, displayed reduced BDCA-2 expression and constituted only a minority of the BDCA-2-positive cells, at least in healthy control PBMCs (median 18%). IFN alpha production by both SLE and healthy control PBMCs stimulated by SLE-IIF or HSV-1 was markedly reduced by anti-BDCA-2 mAb (median 81-98% inhibition). Anti-BDCA-4 mAb only partially inhibited SLE-IIF-induced IFN alpha production. CONCLUSION: SLE patients had a reduced number of BDCA-2-expressing PDCs, also termed natural IFN alpha-producing cells, and their IFN alpha production could be inhibited by anti-BDCA-2/4 mAb. Such mAb may be a therapeutic option for inhibiting the ongoing IFN alpha production in SLE patients.
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| 16. |
- Blomberg, Stina, et al.
(författare)
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Presence of cutaneous interferon-alpha producing cells in patients with systemic lupus erythematosus
- 2001
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Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 10:7, s. 484-90
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Tidskriftsartikel (refereegranskat)abstract
- Systemic lupus erythematosus (SLE) patients have increased levels of interferon-alfa (IFN-alpha) in the circulation but a reduced number of functionally intact natural IFN-alpha producing cells (IPC) in peripheral blood. In search for tissue localisation of activated IPC, we investigated skin biopsies from SLE patients for the occurrence of such cells. Eleven SLE patients with inflammatory skin lesions and six healthy controls were biopsied. An immunohistochemical technique (IH) and in situ hybridisation (ISH) were used to detect intracellular IFN-alpha protein and IFN-alpha mRNA, respectively. In all 11 biopsies from SLE lesions, a high number of IPC were detected by IH. In the nonlesional SLE biopsies we could also demonstrate IPC in 10/11 patients. In 6/11 SLE patients, IFN-alpha mRNA containing cells could be detected in the specimens. A low number of IPC were detected in 1/6 healthy controls by IH, but no ISH positive cells were seen. Our results demonstrate that SLE patients have active IPC in both dermal lesions and in noninflammatory skin. A recruitment of IPC from blood to peripheral tissues may explain the low number of circulating natural IPC in SLE patients. Because the type I IFN system is involved in the SLE disease process, these results are of interest for the understanding of the pathogenesis in SLE.
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| 17. |
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| 18. |
- 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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| 19. |
- Bremer, Hanna, et al.
(författare)
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ILF2 and ILF3 are autoantigens in canine systemic autoimmune disease
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Dogs can spontaneously develop complex systemic autoimmune disorders, with similarities to human autoimmune disease. Autoantibodies directed at self-antigens are a key feature of these autoimmune diseases. Here we report the identification of interleukin enhancer-binding factors 2 and 3 (ILF2 and ILF3) as autoantigens in canine immune-mediated rheumatic disease. The ILF2 autoantibodies were discovered in a small, selected canine cohort through the use of human protein arrays; a method not previously described in dogs. Subsequently, ILF3 autoantibodies were also identified in the same cohort. The results were validated with an independent method in a larger cohort of dogs. ILF2 and ILF3 autoantibodies were found exclusively, and at a high frequency, in dogs that showed a speckled pattern of antinuclear antibodies on immunofluorescence. ILF2 and ILF3 autoantibodies were also found at low frequency in human patients with SLE and Sjogren's syndrome. These autoantibodies have the potential to be used as diagnostic biomarkers for canine, and possibly also human, autoimmune disease.
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| 20. |
- Burska, Agata, et al.
(författare)
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Type I interferon pathway assays in studies of rheumatic and musculoskeletal diseases : a systematic literature review informing EULAR points to consider
- 2023
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Ingår i: RMD Open. - : BMJ Publishing Group Ltd. - 2056-5933. ; 9:1
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Forskningsöversikt (refereegranskat)abstract
- ObjectivesTo systematically review the literature for assay methods that aim to evaluate type I interferon (IFN-I) pathway activation and to harmonise-related terminology.MethodsThree databases were searched for reports of IFN-I and rheumatic musculoskeletal diseases. Information about the performance metrics of assays measuring IFN-I and measures of truth were extracted and summarised. A EULAR task force panel assessed feasibility and developed consensus terminology.ResultsOf 10 037 abstracts, 276 fulfilled eligibility criteria for data extraction. Some reported more than one technique to measure IFN-I pathway activation. Hence, 276 papers generated data on 412 methods. IFN-I pathway activation was measured using: qPCR (n=121), immunoassays (n=101), microarray (n=69), reporter cell assay (n=38), DNA methylation (n=14), flow cytometry (n=14), cytopathic effect assay (n=11), RNA sequencing (n=9), plaque reduction assay (n=8), Nanostring (n=5), bisulphite sequencing (n=3). Principles of each assay are summarised for content validity. Concurrent validity (correlation with other IFN assays) was presented for n=150/412 assays. Reliability data were variable and provided for 13 assays. Gene expression and immunoassays were considered most feasible. Consensus terminology to define different aspects of IFN-I research and practice was produced.ConclusionsDiverse methods have been reported as IFN-I assays and these differ in what elements or aspects of IFN-I pathway activation they measure and how. No 'gold standard' represents the entirety of the IFN pathway, some may not be specific for IFN-I. Data on reliability or comparing assays were limited, and feasibility is a challenge for many assays. Consensus terminology should improve consistency of reporting.
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| 21. |
- Båve, Ullvi, et al.
(författare)
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Activation of the type I interferon system in primary Sjögren's syndrome : a possible etiopathogenic mechanism
- 2005
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 52:4, s. 1185-1195
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Tidskriftsartikel (refereegranskat)abstract
- Objective The etiopathogenesis of primary Sjögren's syndrome (SS) is largely unknown. In other autoimmune diseases, type I interferon (IFN) may play a pivotal role by triggering and sustaining the disease process. We therefore aimed to determine whether patients with primary SS had an activated type I IFN system. Methods Salivary gland biopsy specimens and sera from patients with primary SS were investigated for the occurrence of IFNα-producing cells and measurable IFNα levels, respectively. The ability of primary SS sera together with apoptotic or necrotic cells to induce IFNα production in normal peripheral blood mononuclear cells was examined. The IFNα inducer was characterized, and IFNα-producing cells were identified. Clinical data were correlated with the IFNα-inducing capacity of primary SS sera. Results Numerous IFNα-producing cells were detected in salivary gland biopsy specimens, despite low serum IFNα levels. Autoantibodies to RNA-binding proteins, combined with material released by necrotic or late apoptotic cells, were potent inducers of IFNα production in plasmacytoid dendritic cells (PDCs). This appeared to be attributable to RNA-containing immune complexes triggering PDCs by means of RNA and interaction with Fcγ receptor IIa. The IFNα-inducing capacity of sera was associated with positive results of a labial salivary gland biopsy (focus score ≥1) and with dermatologic, hematologic, and pulmonary manifestations. Conclusion Patients with primary SS have an activated type I IFN system. Although virus may initiate the production of IFN, the continued IFNα synthesis is caused by RNA-containing immune complexes that activate PDCs to prolong IFNα production at the tissue level. This IFNα promotes the autoimmune process by a vicious circle–like mechanism, with increased autoantibody production and formation of more endogenous IFNα inducers.
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| 22. |
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| 23. |
- Båve, Ullvi, et al.
(författare)
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Fc gamma RIIa is expressed on natural IFN-alpha-producing cells (plasmacytoid dendritic cells) and is required for the IFN-alpha production induced by apoptotic cells combined with lupus IgG
- 2003
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Ingår i: Journal of Immunology. - : American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 171:6, s. 3296-302
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Tidskriftsartikel (refereegranskat)abstract
- An ongoing production of IFN-alpha may be of etiopathogenic significance in systemic lupus erythematosus (SLE). It may be due to the natural IFN-producing cells (NIPC), also termed plasmacytoid dendritic cells (PDC), activated by immune complexes that contain nucleic acids derived from apoptotic cells. We here examined the role of FcgammaR in the IFN-alpha production in vitro by PBMC induced by the combination of apoptotic U937 cells and autoantibody-containing IgG from SLE patients (SLE-IgG). The Fc portion of the SLE-IgG was essential to induce IFN-alpha production, because Fab fragments or F(ab')(2) were ineffective. Normal, especially heat-aggregated, IgG inhibited the IFN-alpha production, suggesting a role for FcgammaR on PBMC. Using blocking anti-FcgammaR Abs, the FcgammaRIIa,c (CD32) but not FcgammaRI or FcgammaRIII were shown to be involved in the IFN-alpha induction by apoptotic cells combined with SLE-IgG, but not by HSV or CpG DNA. In contrast, the action of all of these inducers was inhibited by the anti-FcgammaRIIa,b,c mAb AT10 or heat-aggregated IgG. Flow cytometric analysis revealed that approximately 50% of the BDCA-2-positive PBMC, i.e., NIPC/PDC, expressed low but significant levels of FcgammaRII, as did most of the actual IFN-alpha producers activated by HSV. RT-PCR applied to NIPC/PDC purified by FACS demonstrated expression of FcgammaRIIa, but not of FcgammaRIIb or FcgammaRIIc. We conclude that FcgammaRIIa on NIPC/PDC is involved in the activation of IFN-alpha production by interferogenic immune complexes, but may also mediate inhibitory signals. The FcgammaRIIa could therefore have a key function in NIPC/PDC and be a potential therapeutic target in SLE.
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| 24. |
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| 25. |
- Carlsson Almlöf, Jonas, et al.
(författare)
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Contributions of de novo variants to systemic lupus erythematosus
- 2021
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Ingår i: European Journal of Human Genetics. - : Springer Nature. - 1018-4813 .- 1476-5438. ; 29:1, s. 184-193
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Tidskriftsartikel (refereegranskat)abstract
- By performing whole-genome sequencing in a Swedish cohort of 71 parent-offspring trios, in which the child in each family is affected by systemic lupus erythematosus (SLE, OMIM 152700), we investigated the contribution of de novo variants to risk of SLE. We found de novo single nucleotide variants (SNVs) to be significantly enriched in gene promoters in SLE patients compared with healthy controls at a level corresponding to 26 de novo promoter SNVs more in each patient than expected. We identified 12 de novo SNVs in promoter regions of genes that have been previously implicated in SLE, or that have functions that could be of relevance to SLE. Furthermore, we detected three missense de novo SNVs, five de novo insertion-deletions, and three de novo structural variants with potential to affect the expression of genes that are relevant for SLE. Based on enrichment analysis, disease-affecting de novo SNVs are expected to occur in one-third of SLE patients. This study shows that de novo variants in promoters commonly contribute to the genetic risk of SLE. The fact that de novo SNVs in SLE were enriched to promoter regions highlights the importance of using whole-genome sequencing for identification of de novo variants.
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