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Autoantibody profiling in patients with very early rheumatoid arthritis: a follow-up study
  1. V Nell-Duxneuner1,
  2. K Machold1,
  3. T Stamm1,
  4. G Eberl2,
  5. H Heinzl3,
  6. E Hoefler2,
  7. J S Smolen1,2,4,
  8. G Steiner1,4
  1. 1
    Division of Rheumatology, Department of Internal Medicine III, Medical University of Vienna, Austria
  2. 2
    Second Department of Medicine, Hietzing Hospital, Vienna, Austria
  3. 3
    Department of Clinical Biometrics, Medical University of Vienna, Austria
  4. 4
    Cluster for Rheumatology, Balneology and Rehabilitation, Ludwig Boltzmann Institute for Rheumatology and Balneology, Vienna, Austria
  1. Correspondence to G Steiner, Division of Rheumatology, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18–20, A-1090 Vienna, Austria; guenter.steiner{at}meduniwien.ac.at

Abstract

Objective: To investigate time courses of autoantibody profiles in patients with early arthritis.

Patients and methods: A total of 200 patients with very early arthritis (<3 months duration), among them 102 patients with a final diagnosis of rheumatoid arthritis (RA) and 98 with other rheumatic diseases, were followed up for several years. First follow-up testing was performed in all patients (mean 5 months from baseline), and 82 patients with RA and 35 patients without RA were available for last follow-up testing (mean 32 months from baseline). IgM-rheumatoid factor (RF) was measured by nephelometry, IgA-RF, IgG-RF and anti-cyclic citrullinated peptide antibodies (ACPA) by ELISA, and anti-RA33 antibodies were determined by immunoblotting.

Results: At baseline, IgA-RF was detectable in 29% and IgG-RF in 14% of patients with RA while IgM-RF>50 IU/ml (RF50) was positive in 45% of the patients; specificities were 97%, 99% and 96%, respectively. However, the vast majority of patients positive for IgA-RF or IgG-RF were also positive for RF50 or ACPA. During follow-up, the prevalence of ACPA slightly increased while prevalence of all RF subtypes and anti-RA33 decreased. Remarkably, the number of patients positive for RF50 and/or ACPA remained constant, and these patients had a highly increased risk for developing erosive disease in contrast to patients solely positive for anti-RA33.

Conclusions: Testing for RF subtypes did not provide additional diagnostic information. Patients positive for RF50 and/or ACPA had an unfavourable prognosis, irrespectively of changes in the antibody profile during follow-up, whereas anti-RA33 positivity was inversely associated with erosiveness at baseline and at later time points.

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Footnotes

  • Funding This work was supported by CeMM, Center for Molecular Medicine of the Austrian Academy of Sciences and by funding from the EU Framework 6 Integrated Project AUTOCURE (LSHB-CT-2006-018661).

  • Competing interests None declared.

  • Ethics approval Ethics approval was granted by the Medical University of Vienna.

  • Present address for VN-D: Fourth Medical Department of Medicine, Hanusch Hospital, Vienna, Austria.

  • Provenance and Peer review Not commissioned; externally peer reviewed.

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