To analyze the clinical features and laboratory data of 11 patients with macrophage activation syndrome(MAS).

Data of 11 patients with MAS from last 6 years in the Department of Rheumatology, Peking University People's Hospital were collected. The underlying diseases, clinical features, laboratory findings, treatment outcomes and prognosis were analyzed.

Eleven patients were mostly female(aged from 19 to 65 years, 37 ±17). The underlying diseases were systemic lupus erythematosus(n=4), adult-onset Still's disease(n=4)and Sjögren's Syndrome(n=3). MAS was the first symptom in nearly half patients. MAS was characterized by high fever(100%, 11/11), lymphadenopathy(45%, 5/11)and hypersplenomegaly(45%, 5/11). Laboratory data showed cytopenia(91%, 10/11), serum ferritin elevation(100%, 11/11), hypofibrinogenemia(50%, 5/10), hypertriglyceridemia(55%, 6/11)and hemophagocytosis in bone marrow(82%, 9/11). Low NK-cell activity(3/4)and elevation of sCD25(3/3)was the specific manifestation in MAS. Pulmonary infection(36%, 4/11)and hepatic malfunction(64%, 7/11)were common. All patients received corticosteroid, and pulses corticosteroid therapy(methylprednisolone 200-500 mg/d)was used in 8 patients. Seven were treated with combined immunosuppressants. Eighty-two percent recovered, two patients died. Alive patients were stable during the follow-up.

MAS is commonly seen in the initial onset of autoimmune disease. MAS occurrs simultaneously with multiple systemic diseases and is often difficult to distinguish from active autoimmune diseases. High fever, remarkable serum ferritin elevation and elevation of sCD25 are more common in MAS secondary to autoimmune disease. Corticosteroids, immunosuppressant and intravenous immunoglobulin may improve the prognosis of MAS.

Macrophage activation syndrome; Autoimmune diseases; Lymphohistiocytosis, hemophagocytic; Treatment outcome; Prognosis