Atopy and systemic onset juvenile idiopathic arthritis (SoJIA) are two potential outcomes of a dysregulated immune system. Although rare, SoJIA causes 60% of the morbidity of JIA patients which exhibit a wide heterogeneity of prognosis and treatment. Co-morbidities can complicate the responses to therapy.
To study the influence of co-existing atopy on the prognosis of SoJIA.
Patients diagnosed with SoJIA between Jan 2006 and Sep 2010 were screened, enrolled in this prospective cohort study, and followed for 2 years. Management of SoJIA patients was assessed by ACR Pedi30/50/70 criteria, laboratory variables, and systemic feature score.
At disease onset, 61 SoJIA patients (34 male and 27 female) were enrolled and were divided into SoJIA patients with atopy (n = 27) or those without atopy (n = 34). Atopic group at disease onset had significantly higher numbers of affected joints, ferritin levels and IgE serum levels than the non-atopic group. At 3 and 6 months, fewer SoJIA patients with atopy reached the ACR Pedi50 criteria (p < 0.02). During the 2 years of follow-up time, the number of infections and the number of flares were significantly higher in the SoJIA with atopy group (p < 0.01).
Atopy may exert an adverse influence on SoJIA, as patients with atopy had a more active disease at diagnosis and poorer outcome. This prospective study showed that the TH1/TH2 hypothesis was too simplistic to explain the interaction between atopy and SoJIA.