A diagnosis of SD associated MAS was made and the patient was treated with high-dose intravenous methylprednisolone 1 g daily for three days, cyclosporine 5 mg/ kg daily and supportive noradrenalin due to her low blood pressure (50/30 mmHg). With this treatment her fever gradually diminished after two days and laboratory values showed a slow improvement: a decline in leukocytosis to normal range 9.5 (4-0 10E9/l) with 75% neutrophils, a decline in serum ferritin levels to 900 ng/ml (10 to 120 ng/ml), ESR at 30 mm/1 hour and CRP at 2.9. Her serum fibrinogen and the coagulation profile became normal. Her platelet count normalized after nine days of treatment. Her repeated serum level of beta 2 microglobilin declined to 2600 mg/ml (normal value <2000). Her serum IL-2R was 560 IU/ml (normal value <500 IU/ml) and her serum TNF was lower than 20 pg/ml.