Clinical and laboratory parameters of index case (patient A). Body temperature and laboratory parameters included in the diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH) according to the Histiocyte Society (panels 1-5) and liver parameters (panel 6) are charted for the first 50 days after admission. Black lines indicate tonsillectomy, treatment with rituximab (day 20, 412 mg/m2), and 2 doses of etoposide (days 26 and 33, 100 mg/m2). The shaded area represents days with administrated intravenous immunoglobulin (IVIG; day 17 and days 19-22; 0.17 g/kg and 0.40 g/kg per day, respectively).