COMPARISON OF RHG-CSF PRIMED BONE-MARROW AND BLOOD STEM-CELL AUTOGRAFTS - AN ANALYSIS OF ENGRAFTMENT IN MALIGNANT-LYMPHOMAS AND SOLID TUMORS

Many studies have documented faster engraftment after transplantation with peripheral blood stem cells (PBSC) compared to bone marrow (BM) s tem cells. Most comparisons, however, have been between unprimed BM an d primed PBSC. We have collected engraftment data on 39 patients from 4 Danish centres and compared G-CSF primed BM with G-CSF primed PBSC i n malignant lymphoma and solid tumours. In the lymphoma group 6 BM tra nsplants were compared with 8 PBSC transplants, whereas in the testicu lar cancer group 16 BM transplants were compared with 9 PBSC transplan ts. In the lymphoma group, the time to platelet engraftment (platelets >20x10(9)/l unsupported) was median 15 d in PBSC transplants and medi an 34 d in BM transplants (p=0.003). In the solid tumour patients the difference in time to platelet engraftment was 11 and 18 d in PBSC and BM transplants, respectively (p<0.0001). In an attempt to explain thi s difference we performed CD34(+) subset analysis of BM and PBSC. This analysis revealed a higher content of lineage restricted cells (CD34( +)CD61(+) and CD34(+)GlyA(+)) in PBSC compared to BM. In conclusion, G -CSF mobilized PBSC seems to result in faster engraftment than G-CSF p rimed BM, which could be explained by an increased number of lineage s pecific progenitors in PBSC compared to BM.