IL1B and macrophage activation syndrome: In addition, the IL-1 inhibitor anakinra has been associated with a reduction in C-reactive protein and ferritin levels in patients with MAS diagnosed with sJIA.[11] Masaki et al found that compared to untreated patients with sJIA-associated MAS, patients treated with tocilizumab-treated sJIA-associated MAS had significantly reduced fever and levels of ferritin, triglycerides, and C-reactive protein.