Antinuclear antibody-positive cohort constitutes homogeneous entity in juvenile idiopathic arthritis

To identify a homogeneous entity for antinuclear antibody (ANA)-positive patients suffering from juvenile idiopathic arthritis (JIA).

All of the clinical features were recorded retrospectively. ANA positivity was defined as more than twice positive results at a titer of > 1:100. The correlation between ANA positivity and clinical parameters was assessed by multiple logistic regression analysis.

Of 120 patients, 49 patients were ANA positive (31 oligoarthritis, 18 rheumatoid factor [RF]-negative polyarthritis) and 71 patients were ANA negative (48 oligoarthritis, 23 RF-negative polyarthritis), and were recruited retrospectively to this study according to the International League of Associations for Rheumatology (ILAR) criteria. In ANA-positive cohort, the characteristics of early-onset age, female predominance, and asymmetric arthritis were observed compared with ANA-negative cohort including oligoarthritis and RF-negative polyarthritis. Correspondingly, we found that ANA-positive cohort had higher cumulative number of joints affected at 9 and 12 months after disease presentation than ANA-negative cohort, had lower frequency of occurrence of image change, and had a different pattern of affected arthritis than ANA-negative cohort, which was more likely to have knee involvement and less likely to have hip and shoulder involvement. ANA positivity correlated strongly with asymmetric arthritis, female predominance and wrist involvement.

This study demonstrates that ANA-positive cohort divided into different subgroups by present ILAR criteria share the similar features and suggests that ANA positivity might serve as a novel potential value for JIA classification.