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- Bienaime, Frank, et al.
(författare)
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Mutations in components of complement influence the outcome of Factor I-associated atypical hemolytic uremic syndrome
- 2010
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Ingår i: Kidney International. - : Elsevier BV. - 1523-1755 .- 0085-2538. ; 77:4, s. 339-349
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Tidskriftsartikel (refereegranskat)abstract
- Genetic studies have shown that mutations of complement inhibitors such as membrane cofactor protein, Factors H, I, or B and C3 predispose patients to atypical hemolytic uremic syndrome (aHUS). Factor I is a circulating serine protease that inhibits complement by degrading C3b and up to now only a few mutations in the CFI gene have been characterized. In a large cohort of 202 patients with aHUS, we identified 23 patients carrying exonic mutations in CFI. Their overall clinical outcome was unfavorable, as half died or developed end-stage renal disease after their first syndrome episode. Eight patients with CFI mutations carried at least one additional known genetic risk factor for aHUS, such as a mutation in MCP, CFH, C3 or CFB; a compound heterozygous second mutation in CFI; or mutations in both the MCP and CFH genes. Five patients exhibited homozygous deletion of the Factor H-related protein 1 (CFHR-1) gene. Ten patients with aHUS had one mutation in their CFI gene (Factor I-aHUS), resulting in a quantitative or functional Factor I deficiency. Patients with a complete deletion of the CFHR-1 gene had a significantly higher risk of a bad prognosis compared with those with one Factor I mutation as their unique vulnerability feature. Our results emphasize the necessity of genetic screening for all susceptibility factors in patients with aHUS. Kidney International (2010) 77, 339-349; doi: 10.1038/ki.2009.472; published online 16 December 2009
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| 2. |
- Dragon-Durey, Marie-Agnès, et al.
(författare)
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Repository of intra-and inter-run variations of quantitative autoantibody assays: A European multicenter study
- 2022
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : De Gruyter Open. - 1434-6621 .- 1437-4331. ; 60:9, s. 1373-1383
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Tidskriftsartikel (refereegranskat)abstract
- No reference data are available on repositories to measure precision of autoantibody assays. The scope of this study was to document inter-and intra-run variations of quantitative autoantibody assays based on a real-world large international data set. Members of the European Autoimmunity Standardisation Initiative (EASI) group collected the data of intra-and inter-run variability obtained with assays quantifying 15 different autoantibodies in voluntary participating laboratories from their country. We analyzed the impact on the assay performances of the type of immunoassay, the number of measurements used to calculate the coefficient of variation (CVs), the nature and the autoantibody level of the internal quality control (IQC). Data were obtained from 64 laboratories from 15 European countries between February and October 2021. We analyzed 686 and 1,331 values of intra-and inter-run CVs, respectively. Both CVs were significantly dependent on: The method of immunoassay, the level of IQC with higher imprecision observed when the antibody levels were lower than 2-fold the threshold for positivity, and the nature of the IQC with commercial IQCs having lower CVs than patients-derived IQCs. Our analyses also show that the type of autoantibody has low impact on the assay' performances and that 15 measurements are sufficient to establish reliable intra-and inter-run variations. This study provides for the first time an international repository yielding values of intra-and inter-run variation for quantitative autoantibody assays. These data could be useful for ISO 15189 accreditation requirements and will allow clinical diagnostic laboratories to assure quality of patient results.
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| 5. |
- 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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