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Extended report
Interleukin 22 serum levels are associated with radiographic progression in rheumatoid arthritis
  1. Jan Leipe,
  2. Markus A Schramm,
  3. Mathias Grunke,
  4. Michael Baeuerle,
  5. Claudia Dechant,
  6. Axel P Nigg,
  7. Matthias N Witt,
  8. Volker Vielhauer,
  9. Christiane S Reindl,
  10. Hendrik Schulze-Koops,
  11. Alla Skapenko
  1. Division of Rheumatology, Medizinische Poliklinik, University of Munich, Munich, Germany
  1. Correspondence to Hendrik Schulze-Koops, Division of Rheumatology, Medizinische Poliklinik, University of Munich, Pettenkoferstrasse 8a, 80336 Munich, Germany; hendrik.schulze-koops{at}


Objectives To study the role of interleukin 22 (IL-22) in rheumatoid arthritis (RA).

Methods IL-22 serum levels were measured in patients with early, treatment-naive RA (n=49) and in 45 age- and sex-matched healthy individuals as controls. Patients were assessed clinically and radiographically at baseline and followed up for 2 years. Correlations of IL-22 serum levels were sought with parameters of disease activity, serological markers, demographic factors and the incidence of erosions. IL-22 production by peripheral blood T cells was investigated by intracellular flow cytometry.

Results 24 of 49 patients with RA demonstrated elevated IL-22 levels compared with the range of healthy controls. At baseline, a high percentage of these patients (8/24, 33%) demonstrated bone erosions, whereas only one patient (4%) from the group with normal IL-22 had erosions. During the 2 years of follow-up, six additional patients with increased IL-22 at baseline developed erosions. In contrast, none of the patients in whom IL-22 levels were normal developed erosions despite similar treatment regimens. Multivariate regression analysis accounting for other parameters predictive for erosions, such as the presence of rheumatoid factor or anti-cyclic citrullinated peptide antibodies and disease activity, showed that elevated IL-22 baseline levels were independently and significantly associated with erosive RA. Cellular analysis demonstrated enhanced expression of IL-22 from CD4 T cells in RA.

Conclusion IL-22 is elevated in the serum of half of the patients with RA. Elevated serum IL-22 allows discrimination between patients with different radiographic progression and indicates a possible involvement of IL-22 in the pathophysiology of RA.

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  • JL and MS contributed equally to this work.

  • Funding This work was supported by the Deutsche Forschungsgemeinschaft, grants SK59/4-1, Schu 786/2-5, the Sonderforschungsbereich 571 (project D9), the Graduiertenkolleg 1202 (project E2) and by the FöFoLe programme of the medical faculty of LMU Munich.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the ethics committee University of Munich.

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