| 1. |
- Wang, Ning, et al.
(författare)
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Serological Assessment for Celiac Disease in IgA Deficient Adults
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:4, s. 0093180-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Selective immunoglobulin A deficiency is the most common primary immunodeficiency disorder that is strongly overrepresented among patients with celiac disease (CD). IgG antibodies against tissue transglutaminase (tTG) and deamidated gliadin peptides (DGP) serve as serological markers for CD in IgA deficient individuals, although the diagnostic value remains uncertain. The aim of this study was to investigate the prevalence of these markers in a large cohort of IgA deficient adults with confirmed or suspected CD and relate the findings to gluten free diet. Methods: Sera from 488,156 individuals were screened for CD in seven Swedish clinical immunology laboratories between 1998 and 2012. In total, 356 out of 1,414 identified IgA deficient adults agreed to participate in this study and were resampled. Forty-even IgA deficient blood donors served as controls. Analyses of IgG antibodies against tTG and DGP as well as HLA typing were performed and a questionnaire was used to investigate adherence to gluten free diet. Available biopsy results were collected. Results: Out of the 356 IgA deficient resampled adults, 67 (18.8%) were positive for IgG anti-tTG and 79 (22.2%) for IgG anti-DGP, 54 had biopsy confirmed CD. Among the 47 IgA deficient blood donors, 4 (9%) were positive for IgG anti-tTG and 8 (17%) for anti- DGP. Four were diagnosed with biopsy verified CD, however, 2 of the patients were negative for all markers. Sixty-eight of 69 individuals with positive IgG anti-tTG were HLA-DQ2/DQ8 positive whereas 7 (18.9%) of the 37 individuals positive for IgG anti-DGP alone were not. Conclusions: IgG anti- tTG seems to be a more reliable marker for CD in IgA deficient adults whereas the diagnostic specificity of anti-DGP appears to be lower. High levels of IgG antibodies against tTG and DGP were frequently found in IgA deficient adults despite adhering to gluten free diet.
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| 2. |
- Alkaissi, Hammoudi, 1983-
(författare)
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Identification of candidate genes involved in Mercury Toxicokinetics and Mercury Induced Autoimmunity
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Autoimmune diseases require the involvement and activation of immune cells and occur when the body builds up an immune response against its own tissues. This process takes place due to the inability to distinguish self-antigen from foreign antigen. Systemic autoimmunity represents an important cause of morbidity and mortality in humans. The mechanisms triggering autoimmune responses are complex and involve a network of genetic factors. Genome wide association study (GWAS) is a powerful method, used to identify genetic risk factors in numerous diseases, such as systemic autoimmune diseases. The goal of GWAS is to identify these genetic risk factors in order to make predictions about who is at risk and investigate the biological process of disease susceptibility. There are several valuable mouse models to investigate the underlying mechanisms causing systemic autoimmune diseases in which mercury induced autoimmunity (HgIA) is a well- established and relevant model. HgIA in mice includes development of autoantibodies, immune complex glomerulonephritis, lymphocyte proliferation, hypergammaglobulinemia and polyclonal B cell activation. In humans, mercury exposure accumulates with considerable concentrations in kidney, liver, and brain. Toxicokinetics of Hg has been studied extensively but the key for inter-individual variation in humans are largely unclear. Differences in accumulation of renal Hg between inbred mouse strains suggest a genetic inter-strain variation regulating retention or/and excretion of Hg.OBJECTIVES: To find loci and candidate genes associated with phenotypes involved in the development of autoimmunity and find candidate genes involved in the regulation of renal Hg excretion.METHODS: MHC II (H-2s) mice were paired (A.SW x B10.S) to obtain F2 offspring exposed to 2.0 or 4.0 mg Hg in drinking water for 6 weeks. Mercury induced autoimmune phenotypes were studied with immunofluorescence (anti-nucleolar antibodies (ANoA)), ELISA anti-DNP/anti-ssDNA (polyclonal B cell activation), anti-chromatin antibodies (ACA) (4.0 mg Hg), and serum IgG1 concentrations. Mercury accumulation in kidney was performed previously and data was included as phenotype. F2 mice exposed to 2.0 mg Hg were genotyped with microsatellites for genome-wide scan with Ion Pair Reverse Phase High Performance Liquid Chromatography (IP RP HPLC). F2 mice exposed to 4.0 mg Hg were genotyped with single nucleotide polymorphisms for genomewide scan with SNP&SEQ technology platform. Quantitative trait loci (QTL) was established with R/QTL. Denaturing HPLC, next generation sequencing, conserved region analysis and genetic mouse strain comparison were used for haplotyping and fine mapping on QTLs associated with Hg concentration in kidney, development of ANoA and serum IgG1 hypergammaglobulinemia. Candidate genes (Pprc1, Bank1 and Nfkb1) verified by additional QTL were further investigated by real time polymerase chain reaction. Genes involved in the intracellular signaling together with candidate genes were included for gene expression analysis.RESULTS: F2 mice exposed to 2.0 mg Hg had low or no development of autoantibodies and showed no significant difference in polyclonal B cell activation in the B10.S and F2 strains. F2 mice exposed to 4.0 mg Hg developed autoantibodies and significantly increased IgG1 concentration and polyclonal B cell activation (anti-DNP). QTL analysis showed a logarithm of odds ratio (LOD) score between 2.9 – 4.36 on all serological phenotypes exposed to 4.0 mg Hg, and a LOD score of 5.78 on renal Hg concentration. Haplotyping and fine mapping associated the development of ANoA with Bank1 (B-cell scaffold protein with ankyrin repeats 1) and Nfkb1 (nuclear factor kappa B subunit 1). The serum IgG1 concentration was associated with a locus on chromosome 3, in which Rxfp4 (Relaxin Family Peptide/INSL5 Receptor 4) is a potential candidate gene. The renal Hg concentration was associated with Pprc1 (Peroxisome Proliferator-Activated Receptor Gamma, Co-activator-Related). Gene expression analysis revealed that the more susceptible A.SW strain expresses significantly higher levels of Nfkb1, Il6 and Tnf than the less susceptible B10.S strain. The A.SW strain expresses significantly lower levels of Pprc1 and cascade proteins than the B10.S strain. Development of ACA was associated with chromosomes 3, 6, 7 and 16 (LOD 3.1, 3.2, 3.4 and 6.8 respectively). Polyclonal B cell activation was associated with chromosome 2 with a LOD score of 2.9.CONCLUSIONS: By implementing a GWAS on HgIA in mice, several QTLs were discovered to be associated with the development of autoantibodies, polyclonal B cell activation and hypergammaglobulinemia. This thesis plausibly supports Bank1 and Nfkb1 as key regulators for ANoA development and HgIA seems to be initiated by B cells rather than T cells. GWAS on renal mercury excretion plausibly supports Pprc1 as key regulator and it seems that this gene has a protective role against Hg.
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| 3. |
- Rönnelid, Johan, et al.
(författare)
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Immune complex-mediated cytokine production is regulated by classical complement activation both in vivo and in vitro
- 2008
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Ingår i: Advances in experimental medicine and biology. - New York, NY : Springer US. - 0065-2598 .- 2214-8019. ; 632, s. 187-201, s. 187-201
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- Immune complexes (IC) induce a number of cellular functions, including the enhancement of cytokine production from monocytes, macrophages and plasmacytoid dendritic cells. The range and the composition of cytokines induced by IC in vitro is influenced by the availability of an intact classical complement cascade during cell Culture, as we have showed in our studies on artificial IC and on cryoglobulins purified from patients with lymphoproliferative diseases. When IC purified from systemic lupus erythematosus sera were used to stimulate in vitro cytokine production, the amount of circulating IC and IC-induced cytokine levels depended both on in vivo classical complement function as well as on the occurrence of anti-SSA, but not on anti-dsDNA or any other autoantibodies. Collectively these findings illustrate that studies on IC-induced cytokine production in vitro requires stringent cell culture conditions with complete control and definition of access to an intact classical complement pathway in the cell cultures. If IC are formed in vivo, the results have to be interpreted in the context of classical complement activation in vivo as well as the occurrence of IC-associated autoantibodies at the time of serum sampling.
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| 4. |
- Åhlin, Erik, 1980-, et al.
(författare)
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Occurrence of rheumatoid arthritis-associated autoantibodies in Sudanese patients with Leishmania donovani infection
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective Our aim with this investigation was to evaluate the occurrence of anti-cyclic citrullinated peptide antibodies (anti-CCP), rheumatoid factor (RF) and circulating immune complexes (IC) in Sudanese patients infected with Leishmania donovani parasite. Methods Serum samples were collected from Leishmania infected patients and healthy Sudanese controls. Sudanese anti-CCP positive RA patients were included as positive controls. Data from all analyses were also compared with Swedish healthy control cohorts. Levels of circulating IC and anti-CCP were measured using ELISA and RF using nephelometry. A control plate with cyclic control peptides containing arginine instead of citrulline was used to evaluate citrulline specific reactivity. Results We demonstrate that sera from Leishmania infected patients are often RF positive, have elevated IC levels and that a substantial number exhibit antibody reactivity towards CCP. However, contrary to what was evident the in Sudanese RA sera, the CCP reactivity was not restricted to citrulline but reacted equally well with the arginine control peptide. Conclusions Our findings stress the importance to interpret a positive CCP test carefully when evaluated in non-rheumatic conditions.
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| 5. |
- Eriksson, Daniel, et al.
(författare)
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Cytokine Autoantibody Screening in the Swedish Addison Registry Identifies Patients With Undiagnosed APS1
- 2018
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 103:1, s. 179-186
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Tidskriftsartikel (refereegranskat)abstract
- Context: Autoimmune polyendocrine syndrome type 1 (APS1) is a monogenic disorder that features autoimmune Addison disease as a major component. Although APS1 accounts for only a small fraction of all patients with Addison disease, early identification of these individuals is vital to prevent the potentially lethal complications of APS1.Objective: To determine whether available serological and genetic markers are valuable screening tools for the identification of APS1 among patients diagnosed with Addison disease.Design: We systematically screened 677 patients with Addison disease enrolled in the Swedish Addison Registry for autoantibodies against interleukin-22 and interferon-α4. Autoantibody-positive patients were investigated for clinical manifestations of APS1, additional APS1-specific autoantibodies, and DNA sequence and copy number variations of AIRE.Results: In total, 17 patients (2.5%) displayed autoantibodies against interleukin-22 and/or interferon-α4, of which nine were known APS1 cases. Four patients previously undiagnosed with APS1 fulfilled clinical, genetic, and serological criteria. Hence, we identified four patients with undiagnosed APS1 with this screening procedure.Conclusion: We propose that patients with Addison disease should be routinely screened for cytokine autoantibodies. Clinical or serological support for APS1 should warrant DNA sequencing and copy number analysis of AIRE to enable early diagnosis and prevention of lethal complications.
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| 6. |
- Kharlamova, N., et al.
(författare)
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False Positive Results in SARS-CoV-2 Serological Tests for Samples From Patients With Chronic Inflammatory Diseases
- 2021
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Patients with chronic inflammatory diseases are often treated with immunosuppressants and therefore are of particular concern during the SARS-CoV-2 pandemic. Serological tests will improve our understanding of the infection and immunity in this population, unless they tests give false positive results. The aim of this study was to evaluate the specificity of SARS-Cov-2 serological assays using samples from patients with chronic inflammatory diseases collected prior to April 2019, thus defined as negative. Samples from patients with multiple sclerosis (MS, n=10), rheumatoid arthritis (RA, n=47) with or without rheumatoid factor (RF) and/or anti-cyclic citrullinated peptide antibodies (anti-CCP2) and systemic lupus erythematosus (SLE, n=10) with or without RF, were analyzed for SARS-CoV-2 antibodies using 17 commercially available lateral flow assays (LFA), two ELISA kits and one in-house developed IgG multiplex bead-based assay. Six LFA and the in-house validated IgG assay correctly produced negative results for all samples. However, the majority of assays (n=13), gave false positive signal for samples from patients with RA and SLE. This was most notable in samples from RF positive RA patients. No false positive samples were detected in any assay using samples from patients with MS. Poor specificity of commercial serological assays could possibly be, at least partly, due to interfering antibodies in samples from patients with chronic inflammatory diseases. For these patients, the risk of false positivity should be considered when interpreting results of the SARS-CoV-2 serological assays.
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| 7. |
- 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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| 8. |
- Frodlund, Martina, et al.
(författare)
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Immunoglobulin A anti-phospholipid antibodies in Swedish cases of systemic lupus erythematosus : associations with disease phenotypes, vascular events and damage accrual
- 2018
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Ingår i: Clinical and Experimental Immunology. - : WILEY. - 0009-9104 .- 1365-2249. ; 194:1, s. 27-38
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Tidskriftsartikel (refereegranskat)abstract
- Immunoglobulin (Ig) G- and IgM-class anti-cardiolipin antibodies (aCL) and lupus anti-coagulant (LA) are included in the 1997 update of the American College of Rheumatology (ACR-97) systemic lupus erythematosus (SLE) criteria. Despite limited evidence, IgA-aCL and IgA anti-(2)-glycoprotein-I (anti-(2)GPI) were included in the 2012 Systemic Lupus International Collaborating Clinics criteria. The present study aimed to evaluate IgG-/IgA-/IgM-aCL and anti-(2)GPI occurrence in relation to disease phenotype, smoking habits, pharmacotherapy, anti-phospholipid syndrome (APS) and organ damage among 526 Swedish SLE patients meeting ACR-97. Patients with rheumatoid arthritis (n=100), primary Sjogren's syndrome (n=50) and blood donors (n=507) served as controls. Anti-phospholipid antibodies (aPL) were analysed by fluoroenzyme-immunoassays detecting aCL/anti-(2)GPI. Seventy-six (14%) SLE cases fulfilled the Sydney APS-criteria, and 1 aCL/anti-(2)GPI isotype (IgG/IgA/IgM) occurred in 138 SLE patients (26%). Forty-five (9%) of the SLE cases had IgA-aCL, 20 of whom (4%) lacked IgG-/IgM-aCL. Seventy-four (14%) tested positive for IgA anti-(2)GPI, 34 (6%) being seronegative regarding IgG/IgM anti-(2)GPI. Six (1%) had APS manifestations but were seropositive regarding IgA-aCL and/or IgA anti-(2)GPI in the absence of IgG/IgM-aPL and LA. Positive LA and IgG-aPL tests were associated with most APS-related events and organ damage. Exclusive IgA anti-(2)GPI occurrence associated inversely with Caucasian ethnicity [odds ratio (OR)=021, 95% confidence interval (CI)=006-072) and photosensitivity (OR=019, 95% CI=005-072). Nephritis, smoking, LA-positivity and statin/corticosteroid-medication associated strongly with organ damage, whereas hydroxychloroquine-medication was protective. In conclusion, IgA-aPL is not rare in SLE (16%) and IgA-aPL analysis may have additional value among SLE cases with suspected APS testing negative for other isotypes of aPL and LA.
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| 9. |
- ElShafie, Amir Ibrahim, et al.
(författare)
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Cystatin C as a marker of immune complex-associated renal impairment in a sudanese population with visceral leishmaniasis
- 2006
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Ingår i: American Journal of Tropical Medicine and Hygiene. - 0002-9637 .- 1476-1645. ; 75:5, s. 864-868
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Tidskriftsartikel (refereegranskat)abstract
- Renal function was studied in visceral leishmaniasis (VL) and post-kala-azar dermal leishmaniasis (PKDL) by means of the specific marker cystatin C and related to circulating immune complexes and cytokine production. Forty patients with VL (23 with sub-acute disease and 17 with acute disease), 17 patients with PKDL, and 22 healthy controls were included. Cystatin C, but not creatinine, was significantly raised in VL (P = 0.004). The highest levels of cystatin C were found in those with acute disease (P < 0.0001). In VL, cystatin C levels were positively correlated to circulating immune complexes and production of granulocyte-macrophage colony stimulating factor (GM-CSF), but negatively correlated to aspartate aminotransferase and lactate dehydrogenase. We conclude that cystatin C is a superior marker of glomerular function in leishmaniasis and that immune complex deposition and GM-CSF are two functions that most likely are causally involved in the mechanisms leading to glomerular dysfunction in leishmaniasis.
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| 10. |
- Mullazehi, Mohammed, 1966-
(författare)
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Anti-Collagen Type II Autoantibodies in an Acute Phenotype of Early Rheumatoid Arthritis
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rheumatoid arthritis (RA) is an autoimmune disease with systemic inflammatory features that primarily affects small peripheral joints. Type II collagen (CII), is the most abundant collagen type in joint cartilage. Antibodies against CII (anti-CII) are found in a subpopulation of RA patients. Anti-CII can form surface-bound immune complexes (IC) in inflamed joints, which might intensify joint inflammation and destruction. In this thesis I have studied the functional effects of surface-bound anti-CII–containing IC in vitro and correlated the results to clinical parameters. Anti-CII IC induced TNF-α, IL-1β and IL-8 production from monocytes via FcγRIIa. Anti-CII levels were dichotomously distributed in RA patients where a small outlier group (3.3%) with very high anti-CII levels showed in vitro induction of pro-inflammatory cytokines by anti-CII-containing IC. These patients also had a distinct phenotype with elevated laboratory signs of inflammation and increased radiological erosions at the time of diagnosis. In another in vitro model, co-cultured macrophages and RA synovial fibroblasts stimulated with anti-CII IC induced the production of matrix metalloproteinases (MMP)-1 and MMP-8, enzymes responsible for the initial cleavage of CII during cartilage degradation. This was mediated via production of TNF-α and IL-1β, and especially anti-CII IC-induced IL-1β sup-ported the production of MMP-1. The presence of anti-CII antibodies in patients with early synovitis was not predictive for future RA development. In summary, I have shown how anti-CII-containing IC may explain part of the early pathogenesis and can define a distinct clinical phenotype in RA patients with high levels of anti-CII.
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