BACKGROUNDThe effects of donor characteristics on CD34(+) cell dose remain controversial. Recently, we developed a novel haploidentical transplant protocol, in which mixture allografts of granulocyte colony-stimulating factor (G-CSF)-primed bone marrow (G-BM) and G-CSF-mobilized peripheral blood (G-PB) were used. The aim of this study was to investigate the effects of donor characteristics on CD34(+) cell dose in mixture allografts of G-BM and G-PB.

METHODSA total of 162 healthy adult donors, who underwent bone marrow harvest and peripheral blood collection between January 2009 and November 2010 in Peking University People's Hospital, were prospectively investigated. G-CSF was administered subcutaneously at a dose of 5 µg/kg once a day for 5-6 consecutive days. Bone marrow and peripheral blood stem cells were harvested on the fourth day and fifth day, respectively. A final total CD34(+) cell dose less than 2×10(6) cells/kg recipient body weight was considered a poor mobilization.

RESULTSOf the 162 donors, 31 (19.1%) did not attain this threshold. The obtained median CD34(+) cell doses in bone marrow, peripheral blood, and mixture allografts were 0.83×10(6)/kg, 2.40×10(6)/kg, and 3.47×10(6)/kg, respectively. Multiple regression analysis showed that donor age had a significant negative effect on CD34(+) cell dose in either G-BM, or G-PB, or mixture allografts of G-BM and G-PB. And a 1-year increase in age was associated with a 5.6% decrease in the odds of achieving mobilization cutoff. No significant correlation was found for donor gender, body mass index (BMI), and weight.

CONCLUSIONDonor age is the only factor among the four parameters, including age, gender, weight, and BMI, that influence CD34(+) cell dose in mixture allografts of G-BM and G-PB, and younger donors should be chosen to obtain sufficient CD34(+) cells for transplantation.