Routine use of Zenit RA, a novel chemiluminescent immunoanalyzer in autoimmune disease diagnosis

Update and clinical management of anti-DNA auto-antibodies

Anti-deoxyribonucleic acid (DNA) antibodies in the clinical laboratory are intimately linked to the diagnosis and monitoring of systemic lupus erythematosus (SLE); however, the characteristics of the analytical methods and the properties of the antibodies themselves are heterogeneous. To review the definition and properties of anti-double-stranded anti-DNA (anti-dsDNA) antibodies, the adequacy of analytical methods, and the clinical requirements for this biomarker. Through PubMed we searched the existing literature with the terms anti-dsDNA, editorial, review, guideline, meta-analysis and SLE. The last search, anti-dsDNA and SLE restricted to the last two years. Information was expanded through related articles and those published in official state bodies related to anti-dsDNA and SLE. Clinical laboratory methods for anti-dsDNA analysis and their characteristics are analyze. The clinical utility of anti-dsDNA in its diagnostic, clinical association and follow-up aspects of SLE is reviewed. There is wide variability in analytical methods and deficits in standardization persist. They are part of the current SLE classification criteria and are used as markers in the follow-up of the disease. Their diagnostic usefulness improves when they are determined in antinuclear antibody (ANA)-positive patients. In follow-up, quantification is of interest, preferably with the same analytical method (given the deficits in standardization).

Position paper: Revised 2017 international consensus on testing of ANCAs in granulomatosis with polyangiitis and microscopic polyangiitis

Anti-neutrophil cytoplasmic antibodies (ANCAs) are valuable laboratory markers used for the diagnosis of well-defined types of small-vessel vasculitis, including granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). According to the 1999 international consensus on ANCA testing, indirect immunofluorescence (IIF) should be used to screen for ANCAs, and samples containing ANCAs should then be tested by immunoassays for proteinase 3 (PR3)-ANCAs and myeloperoxidase (MPO)-ANCAs. The distinction between PR3-ANCAs and MPO-ANCAs has important clinical and pathogenic implications. As dependable immunoassays for PR3-ANCAs and MPO-ANCAs have become broadly available, there is increasing international agreement that high-quality immunoassays are the preferred screening method for the diagnosis of ANCA-associated vasculitis. The present Consensus Statement proposes that high-quality immunoassays can be used as the primary screening method for patients suspected of having the ANCA-associated vaculitides GPA and MPA without the categorical need for IIF, and presents and discusses evidence to support this recommendation.

Zenit RA evaluation, a solid-phase chemiluminescence immunoassay for detection of anti-cellular antibodies

Aim: The objective was to compare Zenit RA chemiluminescent immunoassay (CLIA) from Menarini Diagnostics and ELISA from INOVA Diagnostics for the presence of specific anti-Ro/SS-A, anti-La/SS-B, anti-U1snRNP, anti-Sm, anti-Scl-70, anti-Jo-1 antibodies. Results/methodology: We studied 501 samples (178 connective autoimmune disease, 150 other autoimmune or inflammatory disease and 173 other disease or healthy). All samples were analyzed using CLIA and ELISA. The Kappa agreement was excellent for anti-SSA/Ro (0.864), good for anti-SSB/La (0.735), anti-Scl-70 (0.685) and ENA-screening (0.778), moderate for anti-RNP (0.563) and bad for anti-Sm (0.266) and anti-Jo-1 (0.243). Different combination of cut-off improved the specificity and agreement. Conclusion: Zenit RA CLIA for detecting autoantibodies, provides a simple, useful and accurate tool.