Mononuclear Cells Count Can Reliably Predict Hematopoietic Reconstitution After Allogeneic Peripheral Blood Stem Cell Transplantation

Objective To explore the feasibility of mononuclear cells(MNC) count taken as an index for predicting hematopoietic reconstitution after allogeneic peripheral blood stem cell transplantation(Allo-PBSCT).Methods From January 2000 to December 2007,98 patients(60 male,38 female; median ages of 30 years) underwent Allo-PBSCT in our HSCT unit.98 sibling donors(50 male,48 female;median ages of 28 years) received the unified mobilization regimen:All donors were mobilized with rhG-CSF at a dose of 5μg·kg^-1 s.c.every 12 hours for 5 days,and PBSCs were harvested by Cobe Spectra separator with MNC program on day 5 after rhG-CSF administration.Patients were divided into 2 groups:MNC group(61 patients) and CD34⁺ cell group(37 patients). The target recipient MNC dose collected was 4×10⁸/Kg in MNC group,and the target recipient CD34⁺ cell dose was 4×10⁶/Kg in CD34⁺ cell group.The impacts of MNC count and CD34⁺ cell count on engraftment and number of apheresis were assessed.Resultsâ‘ Amedian of 6.75(3.03～18.57)×10⁸ MNC/Kg was infused into the recipients of MNC group;A median of 5.05(2.06～17.23)×10⁶ CD34⁺ cells/Kg was infused into the recipients of CD34⁺ cell group.â‘¡All recipients obtained complete hematopoietic reconstitution after transplantation(100%).The median time for ANC＞0.5×10⁹/L and PLT＞20×10⁹/L in the recipients from MNC group were day +11(+9～+17) and day +12(+9～+71 ),respectively,and day +11(+9～+27) and day +12(+9～+35) in the recipients from CD34⁺ cell group,respectively.There were no statistically significant differences between the two groups.â‘¢All the 61 donors in MNC group achieved the threshold dose of 3.0×10⁸ MNC/Kg in a single apheresis procedure(100%),as compared with 14 donors in CD34⁺ cells group who achieved the threshold dose of 2.0×10⁶ CD34⁺ cells /Kg in a single apheresis procedure(37.8%)(P=0.000).â‘£The median time for ANC＞0.5×10⁹/L and PLT＞20×10⁹/L in the recipients who received HLA-identical sibling donor transplantation were day +11(+9～+16) and day +12(+10～+17),respectively, and day +12(+9～+71) and day +14(+10～+22) in the recipients who received HLA-mismatched sibling donor transplantation,respectively,and there were no statistically significant differences between the two groups.Conclusion These results indicate that MNC taken as an index for the measurement of the stem cell/progenitor content can reliably predict hematopoietic reconstitution after both HLA-identical and -mismatched sibling donor peripheral blood stem cell transplantation,with the rate and tempo of engraftment comparable with that in CD34⁺ cell group,and the threshold recipient dose was reached with one apheresis in 100%of donors in MNC group,as compared with 37.8%of donors in CD34⁺ cell group,suggesting that MNC may replace CD34⁺ cell as an index for the assessment of the stem cell/progenitor content in clinical practice.