Volume 10 Supplement 1

2011 Pediatric Rheumatology Symposium: Abstracts

Open Access

Presence of anti-cyclic citrullinated peptide antibody isotypes in juvenile idiopathic arthritis synovial fluid indicates autoantibody production at the site of inflammation

  • Brooke E Gilliam1,
  • Sandra Crespo-Pagnussat1,
  • Judy Ko1,
  • Reema H Syed1 and
  • Terry L Moore1
Pediatric Rheumatology201210(Suppl 1):A118

https://doi.org/10.1186/1546-0096-10-S1-A118

Published: 13 July 2012

Purpose

To determine the presence and significance of anti-cyclic citrullinated (anti-CCP) antibody isotypes (IgA, IgG, IgM, and IgA/IgG) in the synovial fluid (SF) of juvenile idiopathic arthritis (JIA) patients.

Methods

Anti-CCP antibody isotypes (IgA, IgG, IgM, and IgA/IgG) were assayed by enzyme-linked immunosorbent assays in the SF of 47 individual JIA patients. Patients included 28 oligoarthritis, 11 IgM RF- polyarthritis, 3 IgM RF+ polyarthritis, 3 enthesitis-related, 1 psoriatic, and 1 systemic-onset. As non-inflammatory controls, 10 patients aspirated SF with osteoarthritis (OA) were used.

Results

Eleven of 47 (23%) JIA SF samples were positive for the different anti-CCP antibody isotypes. IgM anti-CCP antibodies were positive in 9 JIA patients, including 5 oligoarthritis, 3 IgM RF+ and 1 IgM RF- polyarthritis. IgG anti-CCP antibodies were positive in 8 JIA patients, including 4 oligoarthritis, 2 IgM RF+, 1 IgM RF- polyarthritis, and 1 enthesitis-related. Two IgM RF+ polyarthritis patients were positive for IgA anti-CCP antibodies, and also positive for all 3 isotypes. Four JIA patients were positive for 2 anti-CCP antibody isotypes, including 1 IgM RF- polyarthritis patient (IgG and IgM) and 3 oligoarthritis patients (2 IgG and IgM, 1 IgA and IgM). Five JIA patients were positive for 1 anti-CCP antibody isotype, including 3 oligoarthritis (2 IgM, 1 IgG), 1 enthesitis-related (IgG), and 1 IgM RF+ polyarthritis patient (IgM). Three JIA patients were positive for the combined IgA/IgG anti-CCP antibody ELISA, including 2 with IgM RF+ polyarthritis and 1 enthesitis-related. Polyarthritis patients demonstrated significantly higher levels of all anti-CCP antibody isotypes compared to the other JIA subtypes (p<0.05). When only evaluating the IgM RF+ polyarthritis patients against the other subtypes, the levels were even more significantly increased (p<0.05). Serum-matched IgG anti-CCP antibody data was available in 27 JIA patients and 5 healthy controls. All 3 IgM RF+ polyarthritis patients were positive for the IgG anti-CCP antibodies in serum and SF. Two JIA patients who were positive for IgG anti-CCP antibodies in SF had a negative result in serum. Date-matched SF and serum IgM and IgA data was available on 12 JIA patients. More JIA patients were positive for IgA anti-CCP antibodies in serum compared to SF, while SF showed increased positivity for IgM anti-CCP antibodies compared to serum.

Conclusion

While IgG anti-CCP antibodies are found in JIA patients with polyarticular disease, we found that IgM and IgG anti-CCP antibodies were detected in the SF of several subtypes of JIA. The most commonly found anti-CCP antibody isotype in JIA SF was IgM, which may partly be indicative of defective B cell class switching in these patients. IgM also plays a significant role in complement activation, indicating the significance of the complement system in JIA pathogenesis. Measurement of only IgG anti-CCP antibodies would have overlooked 4 JIA patients with elevated levels of IgA and/or IgM anti-CCP antibodies in SF, indicating the importance of measuring all 3 isotypes in SF.

Disclosure

Brooke E. Gilliam: None; Sandra Crespo-Pagnussat: None; Judy Ko: None; Reema H. Syed: None; Terry L. Moore: None.

Authors’ Affiliations

(1)
St. Louis University

Copyright

© Gilliam et al; licensee BioMed Central Ltd. 2012

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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