CD34(-) CELLS INFLUENCE DAYS TO ENGRAFTMENT AND TRANSFUSION REQUIREMENTS IN AUTOLOGOUS BLOOD STEM-CELL RECIPIENTS()CD33()

Purpose: To evaluate the reliability of CD34/CD33 subset enumeration a s a predictor of hematopoietic repopulating potential in autologous bl ood stem-cell transplantation and to determine which patient and treat ment-related factors affect the timing, quantity and type of blood ste m cells mobilized. Patients and Methods: We analyzed blood stem-cell c ollections from 410 consecutive cancer patients who received mobilizat ion therapy and evaluated factors, including CD34(+) subset quantities , that might influence engraftment kinetics and transfusion requiremen ts in autologous blood stem-cell recipients. Results: The majority of patients (97%) mobilized CD34(+)33(-) cells, which were usually collec ted in the greatest quantity on the first day of apheresis. Patients w ho received only growth factor mobilized the highest percentage of CD3 4(+)33(-) cells. Extensive prior chemotherapy limited the collection o f CD34(+)33(-) cells. In addition to patient diagnosis (P < .006) and total CD34(+) cell dose (P = .0001), CD34(+)33(-) cell dose (P < .005) and percentage of CD34(+)33(-) cells (P < .005) were identified as in dependent factors significantly predictive of engraftment kinetics. CD 34(+)33(-) cell dose(R-2 less than or equal to .177; P < .0001)was a s trong and the only significant predictor of RBC and platelet transfusi on requirements. Furthermore, independent of the total CD34(+) cell do se, as the CD34(+)33(-) cell dose increased, days to neutrophil recove ry, days to platelet recovery, and transfusion requirements decreased. Conclusion: These findings show that CD34(+)33(-) cells are readily c ollected in most cancer patients and significantly influence engraftme nt kinetics and transfusion requirements in autologous blood stem-cell recipients. CD34(+)33(-) cell quantity of the blood stem-cell graft a ppears to be a more reliable predictor of hematopoietic recovery rates than total CD34(+) cell quantity in this setting.