Background According to the International League of Associations for Rheumatology ILAR diagnostic criteria, some classifications of the official juvenile idiopathic arthritis JIA seem to represent distinct disease entities (systemic, polyarticular rheumatoid factor positive, oligoarthritis ), however, others seem to possess heterogeneous conditions (polyarticular rheumatoid negative, psoriatic).
Objectives the purpose of this study is to discuss whether antinuclear antibody(ANA)-positive patients suffering from illness in the ILAR categories of oligoarthritis and rheumatoid factor-negative polyarthritis with homogeneous characteristics and to compare these characteristics with those of ANA-negative patients with the same categories of disease.
Methods 120 patients, enrolled in Capital Pediatric Institute Rheumatology and Immunology Department from 2008 to 2011, accord with the ILAR criteria of oligoarthritis or polyarthritis. Of the 120 patients,49 were ANA positive (31 had oligoarthritis, 18 had RF-negative polyarthritis), and 71 were ANA negative (48 had oligoarthritis, 23 had RF- negative polyarthritis).ANA positivity was defined as more than twice positive results at a titer of ≧1:100. All of the clinical features were recorded retrospectively.
Results ANA-positive patients of the two categories were semblable with respect to asymmetric arthritis and female-to-male ratio. Compared with ANA-positive patients with polyarthritis, ANA-negative patients with polyarthritis were a higher frequency of symmetric arthritis at disease presentation and six months after disease presentation, a more cumulative number of joints involved at nine or twelve months after diseasepresentation, and a distinctive type of joints, such as wrist, metacarpophalangeal and hip joints. Multiple logistic regression analysis were performed and the close correction between ANA positivity and asymmetric arthritis, female predominance and wrist involvement were corroborated.
Conclusions JIA patients, who share the similar features including ANA positivity, female predominance and asymmetric arthritis, were divided into different subgroups by present ILAR criteria. The value of ANA positivity as a novel parameter of the present ILAR standard of classification deserves reference.
Acknowledgements We thank LIU Zhe-weifor his help and guidance. The findings and conclusions in this report are those of the authors.
Disclosure of Interest None Declared