Is there any difference in PBPC mobilization between cyclophosphamide plus G-CSF and G-CSF alone in patients with non-Hodgkin's lymphoma?

We attempted to analyze whether the use of high-dose cyclophosphamide (CTX 7g/m(2), group A) plus hematopoietic growth factor (G-CSF) or G-CSF alone (10 mug/Kg. group B) as a mobilizing regimen, could result in harvesting different numbers of CD34+ cells, committed progenitors and CD34+ cells subsets. The number of CD34+ cells considered as the target for each high-dose chemotherapy was greater than or equal to 2 x 10(6)/Kg/bw. Fifteen leukaphereses procedures were necessary in group A, while 16 procedures were performed in group B. We did not observe any difference between the two groups in terms of CD34+ cells/mul in the peripheral blood (117 vs 78; p=NS), whereas in the aphereses product we found a significant difference between the two groups of patients in terms of CD34+ cells (6.41 vs 2.89 x 10(6)/Kg/bw: p=.009). CFU-GM (82.5 vs 52.3 x 10(4)/Kg/bw; p=.04). Interestingly, we noted a different distribution of CD34+/33- cells between the 2 groups (mean value 39% vs 65%, p<.05), whereas we did not find any differences regarding CD34+/38-, CD34+/Thy1+, CD34+/HLADR-. The higher number of CFU-GM/Kg/bw collected in the former group did not translate into a superior plating efficiency (27.75 vs 30.29). Furthermore, we observed a strong correlation between CD34+ cells/l in the peripheral blood and the total number of CD34+ cells in the leukaphereses product (r=0.97), whereas this correlation was not found in group B (r=0.15). In both groups of patients the number of CD34+ cells collected correlated well with CFU-GM (r=0.93; r=0.94), but definitely we did not observe any correlation between CD34+ cells/mul and CFU-GM in patients mobilized with G-CSF alone and this did not allow us to predict the harvest accurately. Finally, we evaluated the engraftment kinetics and we did nor observe any statistically significant difference between the two groups of patients.