The effects of interleukin-2 on bone marrow engraftment in a murine model.

Strategies have been developed to rid bone marrow of microscopic tumor prior to infusion in the autologous bone marrow transplant setting. We have previously demonstrated that recombinant human interleukin-2 (IL-2) is effective in such an experimental setting involving a methylcholanthrene-induced fibrosarcoma in mice. The purpose of the current work was to determine whether IL-2 treatment after, or before and after bone marrow transplantation would influence bone marrow engraftment or degree of hematologic reconstitution. We found that stem cell number (CFU-S) and posttransplant marrow cellularity were comparable in IL-2-treated or saline-treated mice. Furthermore, after engraftment, marrow stem cell and myeloid progenitor cell numbers were greater in the IL-2 treatment group. These results suggest that IL-2 will prove to be safe when administered in bone marrow transplant patients.