{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,30]],"date-time":"2026-10-30T18:26:30Z","timestamp":1793384790654,"version":"4.5.0"},"reference-count":19,"publisher":"BMJ","issue":"2","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["RMD Open"],"accepted":{"date-parts":[[2018,7,6]]},"published-print":{"date-parts":[[2018,7]]},"abstract":"<jats:sec>\n                  <jats:title>Objective<\/jats:title>\n                  <jats:p>As rheumatoid factor (RF) and anticitrullinated protein antibodies (ACPAs) are not routinely tested in idiopathic inflammatory myositis (IIM), little is known about their prevalence and clinical implications in this patient group. In antisynthetase syndrome (ASS), presence of ACPA is reportedly associated with more severe and erosive arthritis. We aim to retrospectively determine the prevalence of RF and ACPA in a cross-sectional cohort of 121 patients diagnosed with IIM and to assess clinical associations.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>Serum samples from 121 patients diagnosed with polymyositis (n=30), dermatomyositis (n=41), ASS (n=37), inclusion body myositis (n=1), necrotising autoimmune myopathy (n=5) or overlap myositis (n=7) were analysed. RF was evaluated by nephelometry (Immage 800, Beckman\u2013Coulter); anti-CCP antibodies were identified using fluoro enzyme immunoassays (Immuno-Cap 250, Thermo Fisher). Values above 40 IU\/mL and 7 U\/mL were considered positive for RF and ACPA, respectively.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>The prevalence of RF and ACPA was 9.09% and 4.96%, respectively. No significant differences were observed between RF\/ACPA positive versus negative patients. There was a numerical trend for RF-positive IIM patients to be older and have lower forced expiratory volume in 1 s\u00a0levels.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>RF and ACPA are prevalent in IIM, although we detected a lower prevalence than reported in previous studies. Presence of these antibodies in patients with\u00a0IIM\u00a0patients is not clinically relevant in our cohort.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1136\/rmdopen-2018-000661","type":"journal-article","created":{"date-parts":[[2018,7,25]],"date-time":"2018-07-25T06:35:12Z","timestamp":1532500512000},"page":"e000661","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":14,"title":["Prevalence and clinical correlates of rheumatoid factor and anticitrullinated protein antibodies in patients with idiopathic inflammatory myopathy"],"prefix":"10.1136","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4045-2146","authenticated-orcid":false,"given":"Veerle","family":"Ide","sequence":"first","affiliation":[{"name":"Department of Rheumatology, University Hospitals Leuven, Leuven, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xavier","family":"Bossuyt","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dani\u00ebl","family":"Blockmans","sequence":"additional","affiliation":[{"name":"Department of General Internal Medicine, University Hospitals Leuven, Leuven, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ellen","family":"De Langhe","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, University Hospitals Leuven, Leuven, Belgium"},{"name":"Laboratory of Tissue Homeostasis and Repair, Department of Development and Regeneration, KU Leuven, Leuven, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2018,7,25]]},"reference":[{"key":"2025090312004676000_4.2.e000661.1","doi-asserted-by":"publisher","DOI":"10.1093\/rheumatology\/kep065"},{"key":"2025090312004676000_4.2.e000661.2","doi-asserted-by":"publisher","DOI":"10.1136\/ard.2006.051391"},{"key":"2025090312004676000_4.2.e000661.3","doi-asserted-by":"crossref","DOI":"10.1002\/jcla.22086","article-title":"Diagnostic value of autoantibodies combined detection for rheumatoid arthritis","volume":"31","author":"Sun","year":"2017","journal-title":"J Clin Lab Anal"},{"key":"2025090312004676000_4.2.e000661.4","doi-asserted-by":"publisher","DOI":"10.1111\/1756-185X.12129"},{"key":"2025090312004676000_4.2.e000661.5","doi-asserted-by":"publisher","DOI":"10.1038\/nri.2016.124"},{"key":"2025090312004676000_4.2.e000661.6","doi-asserted-by":"publisher","DOI":"10.1002\/art.27584"},{"key":"2025090312004676000_4.2.e000661.7","doi-asserted-by":"crossref","DOI":"10.1097\/MD.0000000000000523","article-title":"In antisynthetase syndrome, ACPA are associated with severe and erosive arthritis: an overlapping rheumatoid arthritis and antisynthetase syndrome","volume":"94","author":"Meyer","year":"2015","journal-title":"Medicine"},{"key":"2025090312004676000_4.2.e000661.8","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1007\/s12016-016-8528-9","article-title":"Serum Jo-1 autoantibody and isolated arthritis in the antisynthetase syndrome: review of the literature and report of the experience of AENEAS Collaborative Group","volume":"52","author":"Cavagna","year":"2017","journal-title":"Clin Rev Allergy Immunol"},{"key":"2025090312004676000_4.2.e000661.9","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM197502132920706"},{"key":"2025090312004676000_4.2.e000661.10","doi-asserted-by":"crossref","first-page":"878","DOI":"10.1002\/art.40063","article-title":"Editorial: a new classification of adult autoimmune myositis","volume":"69","author":"Sen\u00e9cal","year":"2017","journal-title":"Arthritis Rheumatol"},{"key":"2025090312004676000_4.2.e000661.11","doi-asserted-by":"crossref","DOI":"10.1136\/bmj.e5244","article-title":"Elevated rheumatoid factor and long term risk of rheumatoid arthritis: a prospective cohort study","volume":"345","author":"Nielsen","year":"2012","journal-title":"BMJ"},{"key":"2025090312004676000_4.2.e000661.12","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2015-208980"},{"key":"2025090312004676000_4.2.e000661.13","doi-asserted-by":"publisher","DOI":"10.3899\/jrheum.131375"},{"key":"2025090312004676000_4.2.e000661.14","doi-asserted-by":"publisher","DOI":"10.1007\/s10165-004-0325-2"},{"key":"2025090312004676000_4.2.e000661.15","doi-asserted-by":"publisher","DOI":"10.1373\/clinchem.2006.078063"},{"key":"2025090312004676000_4.2.e000661.16","first-page":"44","article-title":"Timing of onset affects arthritis presentation pattern in antisyntethase syndrome","volume":"36","author":"Gonz\u00e1lez-Gay","year":"2018","journal-title":"Clin Exp Rheumatol"},{"key":"2025090312004676000_4.2.e000661.17","doi-asserted-by":"crossref","DOI":"10.1007\/s11926-016-0618-4","article-title":"The complex role of the lung in the pathogenesis and clinical outcomes of rheumatoid arthritis","volume":"18","author":"Kelmenson","year":"2016","journal-title":"Curr Rheumatol Rep"},{"key":"2025090312004676000_4.2.e000661.18","doi-asserted-by":"crossref","first-page":"1165","DOI":"10.1002\/art.40066","article-title":"Anti-Citrullinated protein antibodies are associated with neutrophil extracellular traps in the sputum in relatives of rheumatoid arthritis patients","volume":"69","author":"Demoruelle","year":"2017","journal-title":"Arthritis Rheumatol"},{"key":"2025090312004676000_4.2.e000661.19","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2011-200182"}],"container-title":["RMD Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/rmdopen-2018-000661","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,9,3]],"date-time":"2025-09-03T19:00:54Z","timestamp":1756926054000},"score":1,"resource":{"primary":{"URL":"https:\/\/rmdopen.bmj.com\/lookup\/doi\/10.1136\/rmdopen-2018-000661"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,7]]},"references-count":19,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2018,7,25]]},"published-print":{"date-parts":[[2018,7]]}},"alternative-id":["10.1136\/rmdopen-2018-000661"],"URL":"https:\/\/doi.org\/10.1136\/rmdopen-2018-000661","relation":{},"ISSN":["2056-5933"],"issn-type":[{"value":"2056-5933","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,7]]}}}