OBJECTIVETo study the clinical and laboratory features of macrophage activation syndrome (MAS) at the early stage of diagnosis, and to explore a method for early identification of MAS.

METHODSA retrospective analysis was performed for the demographic data, clinical and laboratory features, and treatment outcomes of 21 MAS patients.

RESULTSOf the 21 MAS patients, 14 had systemic juvenile idiopathic arthritis, 5 had Kawasaki disease (KD), and 2 had connective tissue disease (CTD) as primary diseases. The median time of MAS onset was 19 days. The KD patients had the shortest time of MAS onset, while the CTD patients had the longest onset time (P=0.009). The top 10 clinical symptoms were fever (95%), rash (86%), lymph node enlargement (67%), hemophagocytic phenomenon in bone marrow (63%), pulmonary disease (62%), serous effusion (62%), hepatomegaly (52%), cerebrospinal fluid abnormalities (50%), central nervous system damage (43%), and splenomegaly (38%). The median of hemoglobin level was lower than the normal value. The medians of C-reactive protein level and erythrocyte sedimentation rate were higher than the normal values. There were significant increases in serum ferritin, glutamic-pyruvic transaminase, aspartate aminotransferase, lactate dehydrogenase, and triglyceride. The median of fibrinogen level was lower than the normal value. There were significant increases in D-dimer, interleukin-6 (IL-6), interleukin-10 (IL-10), and interferon-γ (IFN-γ). Of the 21 patients, 20 were improved and discharged.

CONCLUSIONSIf patients with rheumatic disease have persistent fever, hepatic dysfunction, coagulation disorders, multiple organ impairment, significantly increased IL-10 and IFN-γ, and a persistent increase in serum ferritin, the development of MAS should be considered.