Recombinant Human Interleukin 6 (Il-6) Is Tolerated At 25% The Adult Maximum Tolerated Dose (Mtd) But Appears To Enhance Hematopoietic Recovery Following Ifosfamide, Carboplatin And Etoposide (Ice) Chemotherapy In Children: Correlation With Induction Of Inflammatory Cytokines And Mobilization Of Early Progenitor Cell Subsets.