Treatment is nowadays applied according to HLH 2004 protocol, which is designed for primary HFS and also used in severe secondary HFS cases. Aggressive immunochemotherapy is given (dexamethasone, cyclosporine A, etoposide and in patients with CNS symptoms or abnormal CSF, also intrathecal methotrexate and corticoids) [2] . After initial treatment, bone marrow transplantation is indicated in primary disease and in severe and persistent secondary HFS [1] . 