{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T07:52:45Z","timestamp":1791013965058,"version":"4.1.0"},"reference-count":0,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T00:00:00Z","timestamp":1790985600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T00:00:00Z","timestamp":1790985600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["acrjournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Arthritis &amp; Rheumatology"],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Plasma calprotectin is a marker of neutrophil activity. Its relation to the clinical phenotype and autoantibodies in rheumatoid arthritis (RA) is only partly understood. We therefore aimed to investigate the association between calprotectin and clinical parameters, CRP, ESR, anti\u2010CCP2 and other anti\u2010modified protein autoantibodies (AMPAs) in patients with RA.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Rheumatoid factor (RF), anti\u2010cyclic citrullinated peptide 2 (CCP2) isotypes and plasma calprotectin were centrally measured in a cross\u2010sectional cohort of 4521 Scandinavian RA patients using fluoroenzyme immunoassays. IgG to 15 citrullinated (Cit) and four carbamylated or acetylated (Carb\/Acet) peptides were measured by multiplex solid\u2010phase array. CRP and ESR values were obtained from clinical measurements at the time of blood sampling.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Calprotectin levels correlated with ESR (\u03c1=0.53), CRP (\u03c1=0.47), VAS pain (\u03c1=0.24), SJC28 (\u03c1=0.39), and TJC28 (\u03c1=0.26; p&lt;0.0001 for all). Patients with both elevated CRP (&gt;10mg\/L) and calprotectin (&gt;15 AU\/ml) (14%, N=613) had significantly higher VAS pain, SJC28, and TJC28 than patients with only elevated CRP (p&lt;0.0001), in early and established disease.<\/jats:p>\n                    <jats:p>Patients with elevated calprotectin, independent of CRP levels, had significantly higher proportions of AMPA positivity including anti\u2010CCP2. When patients were divided into six groups based on increasing number of Cit\/Carb\/Acet\u2010reactivities and anti\u2010CCP2 IgG levels, elevated calprotectin was associated with increasing AMPA load, particularly in the presence of RF IgM. The differences between AMPA load groups remained after adjusting for sex, age, RF IgM, and disease duration.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Plasma calprotectin is positively associated with seropositivity and AMPA load by autoantibody levels and the breadth of the autoantibody response.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/art.70357","type":"journal-article","created":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T07:07:26Z","timestamp":1791011246000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The association between systemic inflammation as measured by calprotectin and autoantibody load in rheumatoid arthritis"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9111-5537","authenticated-orcid":false,"given":"Caroline","family":"Gr\u00f6nwall","sequence":"first","affiliation":[{"name":"Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet Karolinska University Hospital Center for Molecular Medicine  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linda Mathsson","family":"Alm","sequence":"additional","affiliation":[{"name":"Thermo Fisher Scientific  Uppsala Sweden"},{"name":"Department of Immunology, Genetics and Pathology Uppsala University  Uppsala Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3380-5342","authenticated-orcid":false,"given":"Helga","family":"Westerlind","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet  Stockholm 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Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Espen","family":"Haavardsholm","sequence":"additional","affiliation":[{"name":"Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital  Oslo Norway"},{"name":"Faculty of Medicine University of Oslo  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martina","family":"Johannesson","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8441-3093","authenticated-orcid":false,"given":"Tore K.","family":"Kvien","sequence":"additional","affiliation":[{"name":"Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital  Oslo Norway"},{"name":"Faculty of Medicine University of Oslo  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1186-3226","authenticated-orcid":false,"given":"Johan","family":"R\u00f6nnelid","sequence":"additional","affiliation":[{"name":"Department of Immunology, Genetics and Pathology Uppsala University  Uppsala Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6439-397X","authenticated-orcid":false,"given":"Tue Wenzel","family":"Kragstrup","sequence":"additional","affiliation":[{"name":"Department of Biomedicine Aarhus University  Aarhus Denmark"},{"name":"Department of Rheumatology, Silkeborg Regional Hospital  Silkeborg Denmark"},{"name":"Department of Molecular Medicine Aarhus University Hospital  Aarhus 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Rheumatology and Spine Diseases, Rigshospitalet  Glostrup Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hilde Berner","family":"Hammer","sequence":"additional","affiliation":[{"name":"Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital  Oslo Norway"},{"name":"Faculty of Medicine University of Oslo  Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"name":"The Danish Rheumatologic Biobank Study Group, Swedish Rheumatology Quality Register Biobank Study Group(SRQb)","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johan","family":"Askling","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet  Stockholm 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