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- Albrecht, Inka, et al.
(författare)
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Development of autoantibodies against muscle-specific FHL1 in severe inflammatory myopathies
- 2015
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Ingår i: Journal of Clinical Investigation. - : AMER SOC CLINICAL INVESTIGATION INC. - 0021-9738 .- 1558-8238. ; 125:12, s. 4612-4624
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Tidskriftsartikel (refereegranskat)abstract
- Mutations of the gene encoding four-and-a-half LIM domain 1 (FHL1) are the causative factor of several X-linked hereditary myopathies that are collectively termed FHL1-related myopathies. These disorders are characterized by severe muscle dysfunction and damage. Here, we have shown that patients with idiopathic inflammatory myopathies (IIMs) develop autoimmunity to FHL1, which is a muscle-specific protein. Anti-FHL1 autoantibodies were detected in 25% of IIM patients, while patients with other autoimmune diseases or muscular dystrophies were largely anti-FHL1 negative. Anti-FHL1 reactivity was predictive for muscle atrophy, dysphagia, pronounced muscle fiber damage, and vasculitis. FHL1 showed an altered expression pattern, with focal accumulation in the muscle fibers of autoantibody-positive patients compared with a homogeneous expression in anti-FHL1-negative patients and healthy controls. We determined that FHL1 is a target of the cytotoxic protease granzyme B, indicating that the generation of FHL1 fragments may initiate FHL1 autoimmunity. Moreover, immunization of myositis-prone mice with FHL1 aggravated muscle weakness and increased mortality, suggesting a direct link between anti-FHL1 responses and muscle damage. Together, our findings provide evidence that FHL1 may be involved in the pathogenesis not only of genetic FHL1-related myopathies but also of autoimmune IIM. Importantly, these results indicate that anti-FHL1 autoantibodies in peripheral blood have promising potential as a biomarker to identify a subset of severe IIM.
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| 2. |
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| 3. |
- Chemin, Karine, et al.
(författare)
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A Novel HLA-DRB1*10:01-Restricted T Cell Epitope From Citrullinated Type II Collagen Relevant to Rheumatoid Arthritis
- 2016
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Ingår i: Arthritis & Rheumatology. - : Wiley. - 2326-5191 .- 2326-5205. ; 68:5, s. 1124-1135
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Antibodies against citrullinated type II collagen (Cit-CII) are common in the sera and synovial fluid of patients with rheumatoid arthritis (RA); however, the known T cell epitope of CII is not dependent on citrullination. The aim of this study was to identify and functionally characterize the Cit-CII-restricted T cell epitopes that are relevant to RA. Methods. Peripheral blood mononuclear cells (PBMCs) from HLA-DRB1*10:01-positive patients with RA and healthy donors were stimulated in vitro with candidate CII peptides. CD154 up-regulation was measured as a marker of antigen-specific activation, and anti-HLA-DR-blocking experiments confirmed HLA restriction. Cytokine production was measured using a Luminex technique. Direct peptide-binding assays using HLA-DRB1*10:01 and HLA-DRB1*04:01 monomeric proteins were performed. The T cell receptor (TCR) beta-chain of CD154-enriched antigen-specific T cells was analyzed using high-throughput sequencing. Results. A novel Cit-CII peptide was identified based on its ability to activate CD4+ T cells from HLA-DRB1*10:01-positive individuals. When stimulated in vitro, Cit-CII autoreactive T cells produced proinflammatory cytokines. Cit-CII311-325 bound (with low affinity) to HLA-DRB1*10:01 but not to HLA-DRB1*04:01, while the native form was unable to bind either protein. In addition, highly expanded clones were identified in the TCR beta repertoire of Cit-CII311-325-stimulated PBMCs. Conclusion. These results illustrate the ability of the citrullination process to create T cell epitopes from CII, a cartilage-restricted protein that is relevant to RA pathogenesis. The exclusive binding of Cit-CII311-325 to HLA-DRB1*10:01 suggests that recognition of citrullinated epitopes might vary between individuals carrying different RA-associated HLA-DR molecules.
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| 4. |
- Chemin, Karine, et al.
(författare)
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EOMES-positive CD4+ T cells are increased in PTPN22 (1858T) risk allele carriers.
- 2018
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 48:4, s. 655-669
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Tidskriftsartikel (refereegranskat)abstract
- The presence of the PTPN22 risk allele (1858T) is associated with several autoimmune diseases including rheumatoid arthritis (RA). Despite a number of studies exploring the function of PTPN22 in T cells, the exact impact of the PTPN22 risk allele on T-cell function in humans is still unclear. In this study, using RNA sequencing, we show that, upon TCR-activation, naïve human CD4+ T cells homozygous for the PTPN22 risk allele overexpress a set of genes including CFLAR and 4-1BB, which are important for cytotoxic T-cell differentiation. Moreover, the protein expression of the T-box transcription factor Eomesodermin (EOMES) was increased in T cells from healthy donors homozygous for the PTPN22 risk allele and correlated with a decreased number of naïve CD4+ T cells. There was no difference in the frequency of other CD4+ T cell subsets (Th1, Th17, Tfh, Treg). Finally, an accumulation of EOMES+CD4+ T cells was observed in synovial fluid of RA patients with a more pronounced production of Perforin-1 in PTPN22 risk allele carriers. Altogether, we propose a novel mechanism of action of PTPN22 risk allele through the generation of cytotoxic CD4+ T cells and identify EOMES+CD4+ T cells as a relevant T-cell subset in RA pathogenesis.
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| 5. |
- Galindo-Feria, Angeles S., et al.
(författare)
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Proinflammatory Histidyl-Transfer RNA Synthetase-Specific CD4+T Cells in the Blood and Lungs of Patients With Idiopathic Inflammatory Myopathies
- 2020
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Ingår i: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 72:1, s. 179-191
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Tidskriftsartikel (refereegranskat)abstract
- Objective Autoantibodies targeting histidyl-transfer RNA synthetase (HisRS; anti-Jo-1) are common in the idiopathic inflammatory myopathies (IIMs) and antisynthetase syndrome. This study was undertaken to investigate immunity against HisRS in the blood and lungs of patients with IIM/antisynthetase syndrome. Methods Bronchoalveolar lavage (BAL) fluid, BAL fluid cells, and peripheral blood mononuclear cells (PBMCs) from patients with IIM/antisynthetase syndrome (n = 24) were stimulated with full-length HisRS protein or a HisRS-derived peptide (HisRS(11-23)). BAL fluid and PBMCs from patients with sarcoidosis (n = 7) and healthy subjects (n = 12) were included as controls. The CD4+ T cell response was determined according to levels of CD40L up-regulation and cytokine expression using flow cytometry. Anti-Jo-1 autoantibody responses in the serum and BAL fluid were assessed by enzyme-linked immunosorbent assay. Lung biopsy samples from patients with IIM/antisynthetase syndrome (n = 14) were investigated by immunohistochemistry. Results In BAL fluid, CD4+ T cells from 3 of 4 patients with IIM/antisynthetase syndrome responded to stimulation with HisRS protein, as measured by the median fold change in CD40L expresssion in stimulated cells compared to unstimulated cells (median fold change 3.6, interquartile range [IQR] 2.7-14.7), and 2 of 3 patients with IIM/antisynthetase syndrome had the highest responses to HisRS(11-23) (median fold change 88, IQR 27-149)(.) In PBMCs, CD4+ T cells from 14 of 18 patients with IIM/antisynthetase syndrome responded to HisRS protein (median fold change 7.38, IQR 2.69-31.86; P < 0.001), whereas a HisRS(11-23) response was present in 11 of 14 patients with IIM/antisynthetase syndrome (median fold change 3.4, IQR 1.87-10.9; P < 0.001). In the control group, there was a HisRS(11-23) response in 3 of 7 patients with sarcoidosis (median fold change 2.09, IQR 1.45-3.29) and in 5 of 12 healthy controls (median fold change 2, IQR 1.89-2.42). CD4+ T cells from patients with IIM/antisynthetase syndrome displayed a pronounced Th1 phenotype in the BAL fluid when compared to the PBMCs (P < 0.001), producing high amounts of interferon-gamma and interleukin-2 following stimulation. Anti-Jo-1 autoantibodies were detected in BAL fluid and germinal center (GC)-like structures were seen in the lung biopsy samples from patients with IIM/antisynthetase syndrome. Conclusion The results of this study demonstrate a pronounced presence of HisRS-reactive CD4+ T cells in PBMCs and BAL fluid cells from patients with IIM/antisynthetase syndrome as compared to patients with sarcoidosis and healthy controls. These findings, combined with the presence of anti-Jo-1 autoantibodies in BAL fluid and GC-like structures in the lungs, suggest that immune activation against HisRS might take place within the lungs of patients with IIM/antisynthetase syndrome.
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| 6. |
- Herrath, Jessica Alexandra
(författare)
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Regulatory T cells in rheumatoid arthritis : contributions from different functional subsets
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rheumatoid arthritis (RA) is a complex and multifactorial disease characterized by chronic joint inflammation and tissue destruction, which can affect all ethnic groups with a prevalence of 0.5-1%. FOXP3+ regulatory T cells (Treg cells) are crucial for the maintenance of self-tolerance and loss of function or reduced frequencies have been implicated in chronic inflammatory and autoimmune diseases. In patients with inflammatory arthritis including RA, Treg cells are significantly enriched at the site of inflammation compared with levels in the circulation, and are further functional in suppressing autologous effector T cells from both peripheral blood and joint origin. Given the accumulation of functional Treg cells in the rheumatic joint, an unresolved question is why local inflammation processes persist in a chronic way. In this thesis, we investigated the presence, frequency and functionality of different Treg-cell subsets in patients with inflammatory arthritis, and further studied the impact of commonly used treatment regimes on the suppressive capacity of Treg cells. We could show that synovial FOXP3+ Treg cells were increased in frequency compared with peripheral blood, displayed a high degree of FOXP3 demethylation and a low capacity of secreting pro-inflammatory cytokines upon stimulation. Moreover, the activation status of effector T cells and locally produced pro-inflammatory cytokines reduced regulatory Treg cell function in vitro and presumably in the rheumatic joint. Furthermore, expression of CD39, an ecto-nucleotidase, which together with CD73 generates anti-inflammatory adenosine, was significantly increased on synovial FOXP3+ Treg cells. Such FOXP3+CD39+ Treg cells did not produce pro-inflammatory cytokines and were good suppressors of several effector T-cell functions including secretion of IFN-γ and TNF, but did not limit IL-17A, a cytokine implicated in RA pathogenesis. Additional investigations of FOXP3+ Treg cells in the context of Helios, a suggested marker of thymus-derived Treg cells, revealed that synovial Helios+FOXP3+ T cells were abundant in the joint, displayed a more classical Treg-cell phenotype with regard to expression of surface markers and cytokine secretion capacity compared with Helios-FOXP3+ T cells. Finally, biologicals commonly used for the treatment of RA were shown to have profound effects on Treg-cell function, however by different mechanisms. Blocking of IL-6 and TNF by tocilizumab or adalimumab increased suppressive capacity of synovial Treg cells. Abatacept, in contrast, had no beneficial effect on Treg-cell function, but due to its mutual effect on effector and regulatory T cells, the inflammatory pressure in the joint could still be alleviated. In summary, our data suggest that joint-derived Treg cells in general are not impaired in their function and rather the inflammatory pressure needs to be reduced to allow for optimal Treg-cell functionality. Further, this work emphasizes the importance of dissecting synovial Treg-cell subsets to gain a better understanding on how Treg cells could be targeted for the treatment of chronic arthritis. ::doi::10.1002/eji.201041004. ::pmid::21607944 ::isi::000293264300019
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