Granulocyte and granulocyte-macrophage colony-stimulating factors in allografts: Uses, misuses, misconceptions, and future applications

Despite more than 10 years experience using growth factors after allogeneic stem cell transplantation (ASCT), their state in this has not been elucidated. Most studies show that they accelerate myeloid recovery, regardless of whether they are instituted on day 0 or day 10 after transplant. However, this does not correlate with an improvement in the outcome. One disadvantage is that granulocyte colony-stimulating factor (G-CSF) prophylaxis is associated with slower platelet engraftment due to an increase in platelet aggregation. There is also no agreement as regards the value of G-CSF given as prophylaxis after ASCT, the effects on graft-vs-host disease (GVHD), and the survival rate. A large retrospective study from Europe showed that patients with acute leukemia who received bone marrow from HLA-identical siblings and were treated with G-CSF ran a higher risk of acute and chronic GVHD and transplant-related mortality, while the survival and the leukemia-free survival rates were reduced. In contrast, a meta-analysis of 18 small studies showed no evidence of an increase in acute and chronic GVHD, using G-CSF as prophylaxis after ASCT. Two studies from the Center for International Blood and Marrow Transplant Research showed contradictory data. When G-CSF is given to the recipient as prophylaxis, the levels of soluble interleukin-2 receptor-α increase, which aggravates GVHD. When it is given to the donor, G-CSF polarizes T cells to produce T-helper cell-2 cytokines, which reduce GVHD after transplantation. G-CSF has no effect on relapse. Available findings suggest that there is no indication to use G-CSF as prophylaxis after ASCT.