Successful treatment of plasma exchange for refractory systemic juvenile idiopathic arthritis complicated with macrophage activation syndrome and severe lung disease.

We read with great interest the recent article by Saper et al 1 describing high mortality of systemic juvenile idiopathic arthritis (sJIA) patients affected by parenchymal lung disease (LD). LD with sJIA has also been associated with macrophage activation syndrome (MAS).2 While both MAS and LD complicating sJIA are known risk factors for mortality, an effective therapeutic strategy has not been established.3 4 The present case report highlights an exacerbated LD complication in an sJIA patient treated successfully with additional plasma exchange (PE). A 5-year-old boy was diagnosed with sJIA when presenting with arthritis, prolonged fever and a skin rash. His white cell count (WCC, 8.5×109/L), C-reactive protein (CRP, 4.8 mg/dL), ferritin (467 ng/mL) and interleukin (IL)-18 (25 453 pg/mL) levels were elevated on diagnosis. Initial treatment of oral prednisolone at 18 mg/day and oral methotrexate at 6 mg/week was insufficient. Oral cyclosporine was started followed by tocilizumab, but clinical …