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A new interesting article has been published in Rheumatology (Oxford). 2019 Jul 1;58(7):1239-1244. doi: 10.1093/rheumatology/key451. and titled:

Combining immunofluorescence with immunoblot assay improves the specificity of autoantibody testing for myositis.

Authors of this article are:

Infantino M, Tampoia M, Fabris M, Alessio MG, Previtali G, Pesce G, Deleonardi G, Porcelli B, Musso M, Grossi V, Benucci M, Manfredi M, Bizzaro N.

A summary of the article is shown below:

OBJECTIVE: Immunoblot (IB) methods are widely used to detect myositis-specific autoantibodies (MSAs); however, false-positive results are common. In this study, we aimed to determine whether associating the anti-nuclear antibody (ANA) IIF pattern may help to improve the specificity of MSA detection by IB in patients with idiopathic inflammatory myositis (IIM).METHODS: Serum samples from 104 patients presenting with muscle weakness/myalgia and positive to at least one MSA by IB (MYOS12 Diver and MIOS7 Diver, D-tek) were tested for ANAs on HEp-2000 cells (Immuno Concepts). The chi-square test was used to analyse the concordance of the MSA result and its corresponding pattern by ANA testing between patients with and without IIM.RESULTS: Eighty-three of the 104 patients had a diagnosis of definite IIM, while in 21 cases, patients were affected by other autoimmune diseases or various non-systemic diseases. Forty nine of 83 (59%) patients in the IIM group and 4/21 (19%) in the non-IIM group showed a concordance between ANA pattern and MSAs by IB (P < 0.001). MSA monopositivity was significantly associated with IIM (91.6%) compared with 61.9% in the non-IIM group (P = 0.0005).CONCLUSIONS: Considering both the MSA result and its corresponding pattern by ANA testing may help to improve the specificity of MSA detection by IB and to confirm the diagnosis of MSA-associated IIM. The monopositivity of MSAs is an important additional tool to validate IB results.© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Check out the article’s website on Pubmed for more information:

This article is a good source of information and a good way to become familiar with topics such as: ANA pattern;IIM;MSA;algorithm;antibody;combination;immunoblot;immunofluorescence;myositis;specificity.