Association of the Presence of Anti-Carbamylated Protein Antibodies in Early Arthritis With a Poorer Clinical and Radiologic Outcome: Data From the French ESPOIR Cohort

Arthritis Rheumatol. 2017 Dec;69(12):2292-2302. doi: 10.1002/art.40237.


Objective: To assess the prevalence of anti-carbamylated protein (anti-CarP) antibodies in a French cohort of patients with early arthritis and to investigate their association with clinical features, final diagnosis, prognosis, and comorbidities.

Methods: The presence of anti-CarP antibodies among patients with early arthritis in the French Etude et Suivi des Polyarthrites Indifférenciées Récentes (ESPOIR) cohort (n = 720) was determined using enzyme-linked immunosorbent assay. We investigated the prevalence of anti-CarP antibodies in different patient subgroups stratified according to anti-citrullinated protein antibody (ACPA) and/or rheumatoid factor (RF) status. Diagnostic and prognostic values of the test were evaluated in this population.

Results: Anti-CarP antibodies were present in approximately one-third of the patients (32.6%) and in 23.6% of the patients who were seronegative for both RF and ACPA. Anti-CarP positivity was associated with a more active disease status at baseline and over time. Anti-CarP-positive patients had a significantly higher Disease Activity Score in 28 joints using the erythrocyte sedimentation rate at month 36 than anti-CarP-negative patients (3.1 ± 0.11 versus 2.8 ± 0.06; P = 0.03). Anti-CarP-positive early arthritis was associated with a higher risk of developing erosions after 96 months of follow-up (55.6% of anti-CarP-positive patients versus 37.3% of anti-CarP-negative patients) (odds ratio 2.1 [95% CI 1.2-3.6]; P = 0.009). This association was particularly true when anti-CarP was associated with ACPA positivity. Moreover, ACPA positivity alone in early arthritis was not associated with a higher risk of erosive evolution.

Conclusion: Our findings indicate that anti-CarP antibodies are present in one-third of patients with early arthritis and in one-fourth of the RF-negative and ACPA-negative patients. They are particularly associated with a more severe radiographic outcome. Anti-CarP antibody positivity may help to accurately identify those at risk of erosive evolution in an early arthritis population.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anti-Citrullinated Protein Antibodies / blood
  • Arthritis, Rheumatoid / blood*
  • Arthritis, Rheumatoid / diagnostic imaging
  • Arthritis, Rheumatoid / immunology
  • Autoantibodies / blood*
  • Autoantibodies / immunology
  • Cohort Studies
  • Early Diagnosis
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • France
  • Humans
  • Male
  • Middle Aged
  • Peptides, Cyclic / immunology*
  • Prognosis
  • Radiography / statistics & numerical data*
  • Rheumatoid Factor / blood
  • Young Adult


  • Anti-Citrullinated Protein Antibodies
  • Autoantibodies
  • Peptides, Cyclic
  • Rheumatoid Factor