Clinical and biological features of MAS closely resemble reactive hemophagocytic lymphohistocytosis (HLH) and the disease is in fact considered today as a subclass of HLH (secondary), which is induced by heterogeneous disorders including infections, malignant tumors and medications such as gold therapy, Aspirin and other non steroidal antiinflammatory drugs [11] . The exact underlying mechanisms of MAS have not yet been clarified.