Correlation of CD34+ cell counts with volume of bone marrow collected for allogeneic bone marrow harvests

The quantity of bone marrow collected for allogeneic bone marrow transplantation is based on collecting 10 to 15 cc of bone marrow/kg of recipient weight. We hypothesized that the percentage of CD34+ cells collected during a bone marrow harvest decreased at the end of the harvest because of increasing amounts of peripheral blood contamination. We performed a prospective, blinded study in which we measured CD34+ percentages and cell counts at 200-cc intervals during bone marrow harvests from 11 consecutive human leukocyte antigen (HLA)-matched sibling bone marrow donors. We observed that the percentage of CD34+ cells in aspirated bone marrow did not vary significantly from the start to the end of the bone marrow harvest, and the total number of CD34+ cells/kg increased in a linear fashion, thus disproving our original hypothesis. In conclusion, the percentage of CD34+ cells in aspirated bone marrow will remain constant throughout a bone marrow harvest.