Evaluation of the Efficacy and Tolerability of an Exclusion Diet in Patients With Juvenile Idiopathic Arthritis

Inclusion Criteria:

• Confirmed diagnosis of juvenile idiopathic arthritis (JIA) in the forms ofenthesitis-related arthritis and oligoarticular forms according to the ILAR 2001criteria (https://medicalcriteria.com/web/reujia/);

• Age between 6 and 18 years (not yet 18);

• Active disease of mild to moderate severity, assessed through the Juvenile -Arthritis Disease Activity Score (JADAS10) tool (Trincianti C. et al., AmericanCollege Rheumatology, 2021);

• For study groups 2 and 3: failure of ongoing pharmacological therapy at the time ofscreening, defined as a failure to achieve at least a 20% reduction in JADAS10values after 3 months of initiating DMARD therapy or biologic medication, or if thedisease is inactive on such therapy, a 20% increase in those values;

• Signed informed consent.

Exclusion Criteria:

• Patients requiring systemic immunosuppressive therapy for active uveitis;

• Patients undergoing therapy with systemic corticosteroids (defined as prednisoneequivalent >0.5 mg/kg for >7 days) or intra-articular corticosteroids in the 3months prior to enrollment;

• Patients with fecal calprotectin values > 250 mcg/g at the time of screening;

• Use of antibiotics in the month prior to enrollment.