Allogeneic bone marrow transplantation for chronic myeloid leukemia using HLA identical sibling donors primed with G-CSF.

Many studies have shown that G-CSF mobilized peripheral blood progenitor cell transplants (PBPCT) manifests faster recovery kinetics than conventional bone marrow transplants. This potential advantage of PBPCT still needs to be balanced against the risk of acute and chronic GVHD associating with the infusion of 10 - 15 fold higher donor lymphocyte number in unmanipulated allogeneic PBPCT than the marrow graft. To evaluate the effect of G-CSF primed bone marrow as a source of stem cells in the HLA-matched sibling transplantation, G-CSF primed with non-primed donor marrow in engraftment and incidence of GVHD for a homogenous group of patients with chronic myeloid leukemia (CML) were compared. Fifty patients with CML underwent bone marrow transplant, thirty-two donors (study group) were given G-CSF 3 - 4 micro g/kg per day for seven days prior to marrow harvest and eighteen donors (control group) had marrow harvest without G-CSF stimulation. Conditioning regimen consisted of total body irradiation and cyclophosphamide (CY), busulfan and CY, or busulfan, total body irradiation and CY. Both groups received same post-grafting GVHD prophylaxis and postgrafting G-CSF treatment. It was found that G-CSF primed donor marrow yielded with significantly higher number of total nucleated cells as well as CD34(+) cells and CFU-GM compared to non-G-CSF primed marrow (P = 0.001). The median engraftment time for absolute neutrophil (ANC > 0.5 x 10(9)/L) was day 15 (range 10 - 22) in the group of G-CSF primed vs day 21 in the non-primed donor group (P = 0.001). The median time for platelets (> 20 x 10(9)/L) was day 17.5 (range 13 - 28) in the group of G-CSF primed vs day 24 in non-primed group (P = 0.001). The incidence of acute GVHD grade II - IV in G-CSF primed donor group was surprisingly as low,as only two cases of thirty-two transplants (6.3%) with acute GVHD grade II limited to the skin. Whereas, five of eighteen patients (27.8%) in the control group developed acute GVHD grade II - IV (P = 0.032). G-CSF primed donors showed reduced CD4(+) and increased CD8(+) cells, resulting in a significant reduction of CD4(+)/CD8(+) ratio as compared with non-primed marrow. The total CD3(+) cell count kept unchanged in G-CSF primed donors. There were not significant differences in the incidence of the chronic GVHD (24% vs 33.3%), relapse rate (12.5% vs 11.1%) and overall survival rate (78.1% vs 66.7%, P = 0.32) during 6 - 50 months of follow-up. In conclusion, G-CSF primed donor marrow accelerates engraftment. Although G-CSF did not change the total CD3(+) cells in bone marrow, it altered the ratio of CD4(+) and CD8(+) cells and significantly reduced the incidence of acute GVHD.