Macrophage activation syndrome in 13 children with systemic-onset juvenile idiopathic arthritis

Background  Macrophage activation syndrome (MAS) is a severe, potentially life-threatening condition induced by chronic rheumatic diseases, especially systemic-onset juvenile idiopathic arthritis (SoJIA) in childhood. This study aimed to analyze the clinical and laboratory characteristics of systemic-onset juvenile idiopathic arthritis (SoJIA) with macrophage activation syndrome (MAS) in 13 patients. Methods  Clinical and laboratory data of 13 SoJIA patients with MAS treated in our hospital from January 2003 to October 2007 were analyzed. Results  In the 13 patients, 9 were boys and 4 girls aged from 5 months to 12 years. Clinical manifestations were of no typical characteristics including persistent fever, anemia, arthritis, hepatosplenomegaly, lymph-adenopathy, dysfunction of the liver, abnormal fat metabolism, and hemophagocytic cells in the bone marrow. Two patients experienced acute respiratory distress syndrome, two had mutiorgan failure, and three died. The perforin A91V (NCBI:SNP rs35947132) gene in 6 patients was normal. Glucocorticoid and immunoimpressive therapy were effective in all patients and plasmapheresis used in one severe patient was also effective. Conclusions  MAS is a serious complication of JIA, especially systemic-onset juvenile idiopathic arthritis. It is essentially important to recognize and treat MAS earlier in order to lower the mortality.