Etanercept for therapy-resistant macrophage activation syndrome.

Macrophage activation syndrome (MAS) is a severe, potentially fatal complication of childhood rheumatic diseases, especially systemic onset juvenile idiopathic arthritis (SoJIA). We report a 4-year-old girl with probable SoJIA who presented with MAS. She did not respond to pulse methyl prednisolone and Cyclosporine A (CsA). She also failed to respond to intravenous immunoglobulin (IVIG) therapy. Etanercept was started, based on the observation of increased serum levels of tumor necrosis factor-alpha (TNF-alpha) in patients with MAS. Her condition improved following etanercept, suggesting that etanercept might have a therapeutic role in resistant MAS.