Improved survival and marrow engraftment of mice transplanted with bone marrow of GM-CSF-treated donors.

Recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) administered to bone marrow (BM) transplant recipients is associated with earlier recovery. We have investigated the possibility of stimulating normal donor mice in vivo with GM-CSF. Donor balb/c mice were injected i.p. with GM-CSF (5000 u) or saline. Seventy-two hours later 5 x 10(5)BM cells from either GM-CSF-treated or control donors were infused into lethally irradiated (850 R) recipients. In the recipients of BM from GM-CSF-treated donors, significantly higher CFU-S and significantly higher survival rate (57% [n = 65]; vs. 30% [n = 63]; p < 0.05) were noted. Donor mice of the GM-CSF group did not differ in bone-marrow cellularity and composition from their controls. However, recipients of BM from GM-CSF-treated mice had higher blood counts of haemoglobin, leukocytes and platelets compared to controls. These data demonstrate that pretreatment of BM donors with GM-CSF may be of benefit in improving survival and marrow engraftment in mice.