Clinical immunology
Anti-CCP antibodies in children with Juvenile Idiopathic Arthritis (JIA) – diagnostic and clinical significance

Anti-cyclic citrullinated peptide (anti-CCP) antibodies are considered to be a marker of rheumatoid arthritis (RA). However, limited and controversial reports concern this problem in children with juvenile idiopathic arthritis (JIA).

Objective: To access the prevalence and diagnostic value of anti-CCP antibodies in children
with JIA. Sera of 96 JIA children were examined for anti-CCP, IgM rheumatoid factor (IgM-RF)
and anti-nuclear (ANA) antibody levels. Anti-CCP-positivity was correlated with the disease characteristics.

Methods: Sera of 96 JIA children were examined for anti-CCP, IgM rheumatoid factor (IgM-RF) and anti-nuclear (ANA) antibody levels. Anti-CCP-positivity was correlated positively with the disease characteristics. The control group consisted of 22 healthy children.

Results: For anti-CCP, sensitivity was 41.6% and specificity 100%. Anti-CCP were present in both IgM-RF positive and negative sera, in all types of JIA onset, including 40.7% children with early stage of JIA (disease duration <6 months). Anti-CCP levels correlated positively with the high disease activity. All healthy children were anti-CCP-negative. The sensitivity of IgM-RF and ANA were significantly lower (14.5% and 8.3%, respectively).

Conclusion: Anti-CCP antibodies are present in sera of JIA children even at the early stage of the disease, in all subtypes of JIA, in both IgM-RF-positive and IgM-RF-negative cases. Moreover,
anti-CCP antibodies are good markers of disease activity.