| 1. |
- Teesalu, Kaupo, et al.
(författare)
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A modified ELISA for improved detection of IgA, IgG, and IgM anti-tissue transglutaminase antibodies in celiac disease
- 2009
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Ingår i: Clinica Chimica Acta. - : Elsevier BV. - 0009-8981. ; 403:1-2, s. 37-41
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Tidskriftsartikel (refereegranskat)abstract
- Background: Serum IgA antibodies against tissue transglutaminase (tTG) are reliable markers for celiac disease (CD), still the diagnostic performance of anti-tTG immunoassays can be improved. A novel ELISA, using fibronectin (FN) as tTG binding protein, was evaluated for the detection of anti-tTG antibodies in CD. Methods: Sera from 173 children with untreated CD and 97 controls were analyzed for IgA, IgG, and IgM anti-tTG antibodies with ELISA using human recombinant tTG with or without FN. Results: The areas under the ROC (receiver operating characteristic) curves were significantly higher for FN/tTG ELISA compared to tTG ELISA for IgG (0.930 versus 0.809; p < 0.001) and IgM (0.850 versus 0.811; p = 0.019), but not for IgA (0.977 versus 0.970; p = 0.356), respectively. At the fixed diagnostic specificity (100% for IgA and IgM, 99% for IgG), the sensitivity of all three FN/tTG ELISA (92.5% for IgA, 60.7% for IgG, 50.3% for IgM) exceeded those obtained in tTG ELISA (89.0% for IgA, 48.6% for IgG, 38.7% for IgM; p < 0.05). The combined use of IgA- and IgG-FN/tTG ELISA resulted in 95.4% sensitivity and 99.0% specificity for CD. Conclusions: Using FN to bind tTG improves the diagnostic performance of solid phase anti-tTG antibody assays for childhood CD. (C) 2009 Elsevier B.V. All rights reserved.
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| 2. |
- Ananieva, Olga, et al.
(författare)
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Immune responses to bile-tolerant Helicobacter species in patients with chronic liver diseases, a randomized population group, and healthy blood donors
- 2002
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Ingår i: Clinical and Diagnostic Laboratory Immunology. - 1071-412X. ; 9:6, s. 1160-1164
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Tidskriftsartikel (refereegranskat)abstract
- Bile-tolerant Helicobacter species such as Helicobacter pullorum, Helicobacter bilis, and Helicobacter hepaticus are associated with hepatic disorders in animals and may be involved in the pathogenesis of chronic liver diseases (CLD) in humans. Antibody responses to cell surface proteins of H. pullorum, H. bilis, and H. hepaticus in serum samples from patients with CLD, a randomized population group, and healthy blood donors were evaluated by using enzyme linked immunosorbent assay (ELISA). The results were compared with the antibody responses to Helicobacter pylori. For analysis of a possible cross-reactivity between bile-tolerant Helicobacter species and H. pylori, sera from a subpopulation of each group were absorbed with a whole-cell extract of H. pylori and retested by ELISA. Results before absorption showed that the mean value of the ELISA units for H. pullorum was significantly higher in patients with CLD than in healthy blood donors (P = 0.01). Antibody reactivity to cell surface protein of H. hepaticus was also significantly higher in the CLD patients than in the healthy blood donors and the population group (P = 0.005 and P = 0.002, respectively). Following the absorption, antibody responses to H. pullorum decreased significantly in all three groups (P = 0.0001 for CLD patients, P = 0.0005 for the population group, and P < 0.0001 for the blood donors), indicating that cross-reactivity between H. pylori and other Helicobacter spp. occurs. The antibody responses to H. hepaticus and H. bilis in CLD patients remained high following absorption experiments compared to ELISA results before absorption. The significance of this finding requires further investigations.
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| 3. |
- Bonroy, Carolien, et al.
(författare)
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Detection of antinuclear antibodies : recommendations from EFLM, EASI and ICAP
- 2023
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 61:7, s. 1167-1198
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Antinuclear antibodies (ANA) are important for the diagnosis of various autoimmune diseases. ANA are usually detected by indirect immunofluorescence assay (IFA) using HEp-2 cells (HEp-2 IFA). There are many variables influencing HEp-2 IFA results, such as subjective visual reading, serum screening dilution, substrate manufacturing, microscope components and conjugate. Newer developments on ANA testing that offer novel features adopted by some clinical laboratories include automated computer-assisted diagnosis (CAD) systems and solid phase assays (SPA).Methods: A group of experts reviewed current literature and established recommendations on methodological aspects of ANA testing. This process was supported by a two round Delphi exercise. International expert groups that participated in this initiative included (i) the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group “Autoimmunity Testing”; (ii) the European Autoimmune Standardization Initiative (EASI); and (iii) the International Consensus on ANA Patterns (ICAP).Results: In total, 35 recommendations/statements related to (i) ANA testing and reporting by HEp-2 IFA; (ii) HEp-2 IFA methodological aspects including substrate/conjugate selection and the application of CAD systems; (iii) quality assurance; (iv) HEp-2 IFA validation/verification approaches and (v) SPA were formulated. Globally, 95% of all submitted scores in the final Delphi round were above 6 (moderately agree, agree or strongly agree) and 85% above 7 (agree and strongly agree), indicating strong international support for the proposed recommendations.Conclusions: These recommendations are an important step to achieve high quality ANA testing.
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| 4. |
- Falorni, Alberto, et al.
(författare)
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Determination of 21-hydroxylase autoantibodies: inter-laboratory concordance in the Euradrenal International Serum Exchange Program
- 2015
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:11, s. 1761-1770
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Tidskriftsartikel (refereegranskat)abstract
- Background: 21-Hydroxylase autoantibodies (21OHAb) are markers of an adrenal autoimmune process that identifies individuals with autoimmune Addison's disease (AAD). Quality and inter-laboratory agreement of various 21OHAb tests are incompletely known. The objective of the study was to determine inter-laboratory concordance for 21OHAb determinations. Methods: Sixty-nine sera from 51 patients with AAD and 51 sera from 51 healthy subjects were blindly coded by a randomization center and distributed to 14 laboratories that determined 21OHAb, either by an "in-house" assay (n=9) using in vitro-translated S-35-21OH or luciferase-labeled 21OH or a commercial kit with I-125-21OH (n=5). Main outcome measures were diagnostic accuracy of each participating laboratory and inter-laboratory agreement of 21OHAb assays. Results: Intra-assay coefficient of variation ranged from 2.6% to 5.3% for laboratories using the commercial kit and from 5.1% to 23% for laboratories using "in-house" assays. Diagnostic accuracy, expressed as area under ROC curve (AUC), varied from 0.625 to 0.947 with the commercial kit and from 0.562 to 0.978 with "in-house" methods. Cohen's. of inter-rater agreement was 0.603 among all 14 laboratories, 0.691 among "in-house" laboratories, and 0.502 among commercial kit users. Optimized cutoff levels, calculated on the basis of AUCs, increased the diagnostic accuracy of every laboratory (AUC >0.9 for 11/14 laboratories) and increased the Cohen's. of inter-rater agreement. Discrepancies in quantitation of 21OHAb levels among different laboratories increased with increasing autoantibody levels. Conclusions: The quality of 21OHAb analytical procedures is mainly influenced by selection of cutoff value and correct handling of assay materials. A standardization program is needed to identify common standard sera and common measuring units.
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| 5. |
- Kisand, Kai, et al.
(författare)
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Interferon autoantibodies associated with AIRE-deficiency decrease the expression of IFN-stimulated genes
- 2008
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 112:7, s. 2657-2666
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Tidskriftsartikel (refereegranskat)abstract
- Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection. Combining genome-wide expression array with real time RT-PCR assays, we here demonstrate that antibodies against IFN-alpha cause highly significant down-regulation of interferon-stimulated gene expression in cells from APECED patients' blood by blocking their highly dilute endogenous IFNs. This down-regulation was lost progressively as these APECED cells matured in cultures without neutralizing autoantibodies. Most interestingly, a rare APECED patient with autoantibodies to IFN-omega but not IFN-alpha showed a marked increase in expression of the same interferon-stimulated genes. We also report unexpected increases in serum CXCL10 levels in APECED. Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.
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| 6. |
- Pervjakova, Natalia, et al.
(författare)
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Multi-ancestry genome-wide association study of gestational diabetes mellitus highlights genetic links with type 2 diabetes
- 2022
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 31:19, s. 3377-3391
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Tidskriftsartikel (refereegranskat)abstract
- Gestational diabetes mellitus (GDM) is associated with increased risk of pregnancy complications and adverse perinatal outcomes. GDM often reoccurs and is associated with increased risk of subsequent diagnosis of type 2 diabetes (T2D). To improve our understanding of the aetiological factors and molecular processes driving the occurrence of GDM, including the extent to which these overlap with T2D pathophysiology, the GENetics of Diabetes In Pregnancy (GenDIP) Consortium assembled genome-wide association studies (GWAS) of diverse ancestry in a total of 5485 women with GDM and 347 856 without GDM. Through multi-ancestry meta-analysis, we identified five loci with genome-wide significant association (p < 5x10-8) with GDM, mapping to/near MTNR1B (p = 4.3x10-54), TCF7L2 (p = 4.0x10-16), CDKAL1 (p = 1.6 × 10-14), CDKN2A-CDKN2B (p = 4.1x10-9) and HKDC1 (p = 2.9x10-8). Multiple lines of evidence pointed to the shared pathophysiology of GDM and T2D: (i) four of the five GDM loci (not HKDC1) have been previously reported at genome-wide significance for T2D; (ii) significant enrichment for associations with GDM at previously reported T2D loci; (iii) strong genetic correlation between GDM and T2D; and (iv) enrichment of GDM associations mapping to genomic annotations in diabetes-relevant tissues and transcription factor binding sites. Mendelian randomisation analyses demonstrated significant causal association (5% false discovery rate) of higher body mass index on increased GDM risk. Our results provide support for the hypothesis that GDM and T2D are part of the same underlying pathology but that, as exemplified by the HKDC1 locus, there are genetic determinants of GDM that are specific to glucose regulation in pregnancy.
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| 7. |
- Sack, Ulrich, et al.
(författare)
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Quality and best practice in medical laboratories : specific requests for autoimmunity testing
- 2020
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Ingår i: Autoimmun Highlights. - : Springer. - 2038-0305 .- 2038-3274. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Special conditions associated with laboratory autoimmune testing are not well compatible with recent developments in regulatory frameworks such as EN/ISO 15189 accreditation or in vitro diagnostic medical device regulation (IVD-R). In addition, international recommendations, guidelines and disease criteria are poorly defined with respect to requirements on autoantibody testing. Laboratory specialists from Austria, Belgium, Croatia, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, and The Netherlands collected information, reported national experience, and identified quality issues in relation to autoantibody testing that require consensus on interpretation of the regulatory frameworks and guidelines. This process has been organized by the European Autoimmunity Standardisation Initiative (EASI). By identifying the critical items and looking for a consensus, our objective was to define a framework for, in particular, EN/ISO accreditation purposes. Here, we present a review of current publications and guidelines in this field to unify national guidelines and deliver in this way a European handout on quality control and accreditation for laboratories involved in autoantibody testing. We focus on quality items that can be checked during accreditation visits. Despite various local varieties, we encountered an overwhelming dedication to quality assurance in all contributing countries.
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| 8. |
- Uibo, Raivo, et al.
(författare)
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GAD65 Autoimmunity-Clinical Studies
- 2008
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Ingår i: Advances in Immunology. - 0065-2776. ; 100, s. 39-78
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Forskningsöversikt (refereegranskat)abstract
- Type 1 diabetes (TID) in children and particularly in teenagers and adults is strongly associated with autoreactivity to the Mr 65,000 isoform of glutamic acid decarboxylase (GAD65). Autoantibodies to GAD65 are common at the time of clinical diagnosis and may be present for years prior to the onset of hyperglycemia. GAD65 autoantibodies predict conversion to insulin dependence when present in patients classified with type 2 diabetes nowadays more often referred to as patients with latent autoimmune diabetes in the adult (LADA) or type 1,5 diabetes. Analyses of T cells with HLA DRB1*0401-tetramers with GAD65-specific peptides as well as of anti-idiotypic GAD65 autoantibodies suggest that GAD6S auto-reactivity is common. The immunological balance is disturbed and the appearance of GAD65 autoantibodies represents markers of autoreactive loss of pancreatic beta cells. Extensive experimental animal research. in particular of the Non-obese diabetic (NOD) mouse, showed that GAD65 therapies reduce insulitis and prevent spontaneous diabetes. Recombinant human GAD65 produced by current Good Manufacturing Practice (cGMP) and formulated with alum was found to be safe in Phase I and 11 placebo-controlled, double-blind, randomized clinical trials. The approach to modulate GAD65 autoreactivity with subcutaneous immunotherapy (SCIT) showed promise as alum-formulated GAD65 induced a dose-dependent reduction in the disappearance rate of endogenous residual C-peptide production. Additional controlled clinical trials are needed to uncover the mechanisms by which subcutaneous injections of recombinant human GAD65 may alter GAD6S autoreactivity.
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| 9. |
- Viskari, Hanna, et al.
(författare)
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Relationship between the Incidence of Type 1 Diabetes and Enterovirus Infections in Different European Populations : Results from the EPIVIR Project
- 2004
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Ingår i: Journal of Medical Virology. - : John Wiley & Sons. - 0146-6615 .- 1096-9071. ; 72:4, s. 610-617
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of type 1 diabetes varies markedly between countries. As enterovirus infections have been linked to type 1 diabetes, we determined whether this variation correlates with the frequency of enterovirus infections in different Caucasian populations in Europe. Enterovirus antibodies were examined in the background population (1-year-old and 10-14-year-old children) in seven countries with either exceptionally high (Finland and Sweden) or low/intermediate incidence of diabetes (Estonia, Germany, Hungary, Lithuania, Russia) using EIA and neutralisation assays. Enterovirus antibodies were less frequent in countries with high diabetes incidence compared to countries with low diabetes incidence (P < 0.001). This suggests that enterovirus infections are not particularly common in countries with high diabetes incidence. In contrast, there seems to be an inverse correlation between the incidence of type 1 diabetes and enterovirus infections in the background population, which is in line with the previously proposed polio hypothesis according to which the complications of enterovirus infections become more common in an environment with a decreased rate of infections. © 2004 Wiley-Liss, Inc.
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| 10. |
- Vorobjova, Tamara, et al.
(författare)
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Seropositivity to Helicobacter pylori heat shock protein 60 is strongly associated with intensity of chronic inflammation, particularly in antrum mucosa: an extension of an 18-year follow-up study of chronic gastritis in Saaremaa, Estonia
- 2001
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Ingår i: Pathogens and Disease. - 2049-632X. ; 30:2, s. 143-149
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori is a cause of chronic gastritis and leads to development of atrophy in some cases. There is evidence that the heat shock protein 60 (HSP60) of H. pylori is involved in induction of chronic inflammation. Seroprevalence of IgG antibodies to H. pylori HSP60 in an adult cohort from Saaremaa, Estonia (68 persons, median age 57 years), with a high prevalence of antibodies to cell surface proteins of H. pylori (92%) and a well characterized dynamics of chronic gastritis in an 18-year follow-up study, was tested using purified H. pylori HSP60 at a concentration of 1 microg ml(-1) with ELISA. The state of the gastric mucosa and the presence of H. pylori in histological sections in the samples of 1979 and 1997 were assessed in accordance with the Sydney system. Seropositivity for H. pylori HSP60 was 65%. Immunological response to H. pylori HSP60 is associated with the morphological presence of H. pylori in the antrum and corpus (P=0.01) and is strongly correlated with the grade of chronic inflammation, particularly in the antrum mucosa (r=0.34; P=0.003; OR=5.97 (95% CI 1.21-29.3)), but is not associated with development of atrophy during 18 years of follow-up, or with the activity of gastritis. This finding supports the evidence that immunological response to H. pylori HSP60 may play a role in triggering of the inflammatory process in the gastric mucosa.
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