G-CSF-mobilized leukapheresis products: Cellular characteristics and clinical performance in allografting

Twenty-five G-CSF-mobilized leukapheresis products (mLP) were screened for cellular composition, including CD34(+)DR(-), CD34(+)DR(+) and leukocyte profile, to compare with 5 native (unstimulated) LP (nLP) and 16 BM inoculi. G-CSF stimulation led to an increase in CD34(+) cells and CD15(+) cells but did not influence the lymphocyte content of mLP. Two groups of 14 and 16 patients were allografted with phenotypically defined mLP (1-4 mLP were used for each patient) and BM, respectively. mLP used for allografting had significantly more CD34(+) cells, including CD34(+)DR(-) cells, monocytes, T cells, and B cells as compared with BM inoculi. Patients were followed for median observation time of 289 days and 409 days for the mLP (PBPC) and BM groups, respectively. The two groups were well matched in regard to age, sex, and stage of disease, with a slight prevalence of major blood group incompatibility (7 of 14 versus 3 of 16) and a lower donor/recipient weight ratio (0.8 +/- 0.2 vs 1.5 +/- 0.6, p = 0.002) in the PBPC group. Granulocyte and platelet recovery was faster in the PBPC group than in the BM group. The time of reaching 20,000/mu l platelets but Plot 500/mu l granulocytes correlated with the number of CD34+ cells in each inoculum. The survival curves of the PBPC and BM groups were similar, as was the incidence of acute GVHD (aGvHD). This was also valid for aplastic anemia cases (7 and 5 patients in the PBPC and BM group, respectively), who benefited from a high number of CD34(+) grafted cells but did not experience aGvHD. Thus, mLP do not appear to elicit aGvHD with higher frequency than BM and may be preferable for hematotherapy.