Clinical Features and Perforin A91V Gene Analysis in 31 Patients with Macrophage Activation Syndrome and Systemic Juvenile Idiopathic Arthritis in China

To the Editor: Macrophage activation syndrome (MAS) is a severe, potentially fatal complication of rheumatoid disease, especially in systemic juvenile idiopathic arthritis (sJIA). MAS has been considered reactive familial hemophagocytic lymphohistiocytosis (FHLH), and the perforin gene mutations have been identified in some patients diagnosed with the FHLH1,2,3. Vastert, et al 4 have found that the mutation rate of perforin gene A91V was significantly higher in MAS than in sJIA. Perforin deficiency may increase macrophage activation because of an increased production of interferon-γ and … Address correspondence to Dr. Huasong; E-mail: huasongz{at}gmail.com.