Short-term in vivo priming of bone marrow haematopoiesis with rhG-CSF, rhGM-CSF or rhIL-3 before marrow harvest expands myelopoiesis but does not improve engraftment capability.

In an attempt to optimize bone marrow grafts for autologous transplantation 37 sequential patients suffering from various haematological diseases were treated with either recombinant human granulocyte colony-stimulating factor (rhG-CSF) (n = 23) or granulocyte-macrophage CSF (rhGM-CSF) (n = 8) for 5 days or interleukin 3 (rhIL-3) (n = 6) for 10 days before marrow harvest. All patients were in marrow remission at study entry. In contrast to rhIL-3, the administration of rhG-CSF or rhGM-CSF caused a significant (P < 0.01) increase in blood absolute neutrophil count. An increased marrow cellularity and a rise in the myeloid:-erythroid ratio was seen in the majority of patients during therapy, and in the rhIL-3 treated group a rise in the number of megakaryocytes and increased marrow fibrosis was seen in most patients. Moreover, a median of 2-, 5- and 10-fold increase in myeloid progenitors was the result of short-term administration of rhIL-3, rhGM-CSF and rhG-CSF, respectively. However, transplantation performed with primed expanded marrow grafts did not significantly reduce the time to myeloid regeneration when compared to historical controls. In conclusion, the results demonstrate that short-term priming with haematopoietic cytokines before autologous bone marrow stem cell harvest is a safe procedure which effectively expands marrow haematopoisis without enhanced engraftment capability.