This study will be the first controlled study to confirm whether anakinra at dose of 10 mg/kg/day to a maximum of dose of 200 mg/day divided every 12 hours (for children ≤40 kg) or 5 mg/kg/day up to a maximum dose of 400 mg/day divided every 6 hours (children > 40 kg and adults) does not result in increased mortality or infection complications when administered in addition to current UAB standard of care treatment (corticosteroids) to children and adults hospitalized with suspected macrophage activation syndrome.