Autologous Transplant Using Dose-Escalated Total Body Irradiation & Cyclophosphamide & Palifermin for NHL

This is a non-randomized, open-label phase I trial in participants with non-Hodgkin's lymphoma. The preparative regimen will be as follows: Day -10 (prior to transplant) Palifermin treatment to prevent mouth sores Day -9 Palifermin treatment to prevent mouth sores Day -8 Palifermin treatment to prevent mouth sores Day -7 Total Body Irradiation twice a day Day -6 Total Body Irradiation twice a day Day -5 Total Body Irradiation twice a day Day -4 Total Body Irradiation twice a day Day -3 Cytoxan chemotherapy infusion Day -2 Cytoxan chemotherapy infusion Day -1 Day of rest Day 0 Stem cell infusion (bone marrow transplant), Palifermin treatment to prevent mouth sores and G-CSF given daily until stem cells take hold (engraftment) occurs. Day +1 Palifermin treatment to prevent mouth sores Day +2 Palifermin treatment to prevent mouth sores