Because of the high fatality of MAS (>50%), a number of different treatments have been tried to manage this disorder, including use of high-dose steroids, immune suppressants such as cyclosporine, and cytotoxic chemotherapy treatments (etoposide) with variable success and/or severe complications of immune suppression (as may occur with etoposide). A number of recent case reports and case series have reported success using cytokine-blocking therapies such as anakinra in the treatment of MAS that is associated with systemic-onset juvenile idiopathic arthritis and adult Still's disease. Anakinra is a bio-engineered form of the naturally occurring interleukin-1 receptor antagonist (IL-1ra), that blocks the action of interleukin-1, one of the cytokines that is expressed and present in very high amounts in patients who have MAS. Anakinra/Il-1ra is an attractive treatment for patients presenting with clinical features of MAS because it has a relatively short half-life and is easy to administer by subcutaneous injection. In previous trials of its use in patients with clinical features of bacterial sepsis (fever, elevated heart rate, low/falling blood pressure) , it was shown that anakinra does not have a harmful effect but also did not appear to have any benefit with repect to the defined primary outcome of improved survival. However, a recent re-analysis of the data accumulated in these same previous sepsis trials (for which the primary defined outcome was survival) indicates that survival was actually increased in the subgroup of sepsis patients with features of MAS (ferritin elevations in excess of 2,000 ng/ml, signs of coagulopathy, and liver enzyme elevations) who were randomized to receive anakinra compared to the subgroup of sepsis patients with features of MAS who were randomized to receive placebo.