Role of plasma exchange, leukocytapheresis, and plasma diafiltration in management of refractory macrophage activation syndrome.

Macrophage activation syndrome (MAS) is a life-threating complication of systemic juvenile idiopathic arthritis (s-JIA). Steroid and cyclosporine (CsA) are effective for MAS, but, treatment for steroid- and CsA-resistant patients is still challenging. We report the case of steroid and CsA resistant s-JIA associated MAS misdiagnosed as Kawasaki disease (KD), who was successfully treated with the combination of plasma exchange (PE) and leukocytapheresis (LCAP) followed by plasma diafiltration (PDF). PE + LCAP effectively removed proinflammatory cytokines and reduced the number of peripheral white blood cells. Furthermore, PDF also removed proinflammatory cytokines as effectively as PE + LCAP. Early diagnosis of s-JIA is necessary to avoid developing MAS. The measurement of serum ferritin and IL-18 levels are useful for differentiating s-JIA from KD. Apheresis therapies are an alternative option to induce remission for severe patients with steroid- or CsA-resistant MAS.