Early Treatment of Systemic Juvenile Idiopathic Arthritis with Canakinumab and Complete Remission After 2 Years of Treatment Suspension: Case Report of an Adolescent Girl.

Systemic juvenile idiopathic arthritis (sJIA) is an autoinflammatory disease characterised by fever and arthritis. We describe the case of a 14-year-old girl hospitalised with fever associated with rash, myalgia, arthralgia and polyarticular involvement. Examinations revealed increased levels of C-reactive protein, erythrocyte sedimentation rate, ferritin, triglycerides, leukocytes, neutrophils, lactate dehydrogenase, fibrinogen, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and γ-glutamyl transferase (GGT). Bone marrow biopsy showed polyclonal leukocyte activation. A genetic study revealed a heterozygous mutation of the MEFV gene, c.442G>C (E148Q), which is typical of familial Mediterranean fever. However, the genetic pattern was not associated with a history of recurrent fever, aphthous ulcers of the mouth, abdominal pain, arthralgia and rash. Therefore, a diagnosis of sJIA was made. The patient did not respond to non-steroidal anti-inflammatory drugs. Corticosteroids improved biochemical examinations; however, AST, ALT, GGT and glycaemia remained elevated and adverse effects of corticosteroid treatment became evident and therefore corticosteroids were withdrawn. Canakinumab (150 mg/4 weeks subcutaneously) was initiated. Biochemical data returned to normal values and clinical symptoms resolved. After 2.5 years of canakinumab treatment, complete disease remission allowed the prolongation of intervals between doses. When the intervals were longer than 10 weeks we discontinued the treatment. The patient is still in remission 2 years after canakinumab withdrawal.