Anti-cyclic citrullinated peptide antibodies in hepatitis C virus associated rheumatological manifestations and Sjögren’s syndrome
- 1Department of Internal Medicine, Hôpital La Pitié-Salpêtrière, Paris, France
- 2Department of Immunochemistry, Hôpital La Pitié-Salpêtrière
- 3Department of Virology, Hôpital La Pitié-Salpêtrière
- 4Research and Development, Euro Diagnostica BV, Harnhem, Netherlands
- Correspondence to:
Professor Patrice Cacoub
Department of Internal Medicine, Hôpital La Pitié-Salpêtrière, 83 Boulevard de l’Hôpital, 75651 Paris Cedex 13, France;
- Accepted 11 July 2005
Objective: To investigate the diagnostic reliability of anti-CCP antibodies (anti-CCP Ab) in distinguishing hepatitis C virus (HCV) associated rheumatological manifestations and Sjögren’s syndrome from rheumatoid arthritis.
Methods: 147 HCV infected patients (HCV RNA positive) were compared with 64 patients with definite rheumatoid arthritis in a retrospective study. Anti-CCP Ab were detected using the Immunoscan ELISA kit (second generation) and rheumatoid factor (RF) by the FIDIS™ Rheuma kit.
Results: Among the 147 HCV infected patients (77 women; mean (SD) age 58 (16) years), 77 (52%) had a mixed cryoglobulin (MC), 38 (26%) an MC associated systemic vasculitis, 35 (24%) arthralgia/arthritis, and seven (5%) definite Sjögren’s syndrome. HCV infected patients with arthralgia were more often RF positive than those without arthralgia (54% v 27%; p = 0.003), but less often than patients with rheumatoid arthritis (54% v 81%; p = 0.009). Anti-CCP Ab were detected in only two HCV infected patients with arthralgia (5.7%), in none without arthralgia or with Sjögren’s syndrome, and in 78% of patients with rheumatoid arthritis. With a specificity of 93.5% and a positive predictive value of 96% for rheumatoid arthritis, anti-CCP Ab were the most specific biological marker.
Conclusions: Anti-CCP antibodies are very rarely found in HCV infected patients with rheumatological manifestations or Sjögren’s syndrome. They are reliable serological markers to distinguish these from patients with rheumatoid arthritis.
- anti-CCP Ab, anti-cyclic citrullinated peptide antibodies
- AUC, area under the curve
- HCV, hepatitis C virus
- MC, mixed cryoglobulin
- NPV, negative predictive value
- PPV, positive predictive value
- RF, rheumatoid factor