SUBSETS OF CD34(+) CELLS AND RAPID HEMATOPOIETIC RECOVERY AFTER PERIPHERAL-BLOOD STEM-CELL TRANSPLANTATION

Purpose: To study whether there is a relationship between transplanted cell dose and rate of hematopoietic recovery after peripheral-blood stem-cell (PBSC) transplantation, and to obtain an indication whether specific subsets of CD34(+) cell populations contribute to rapid recovery of neutrophils or platelets. Patients and Methods: based on data from 59 patients, we calculated for each day after PBSC transplantation the dose of CD34(+) cells that resulted in rapid recovery of either neutrophils or platelets in the majority (> 70%) of patients. Using dual-color how cytometry, subsets of peripheral-blood CD34(+) cells were quantified and the numbers of CD34(+) cells belonging to each of the reinfused subsets correlated with hematopoietic recovery following high-dose chemotherapy. Results: The calculated threshold values with a high probability of engraftment showed a steep dose-effect relationship between CD34(+) cell dose and time to recovery of both neutrophils or platelets. predominantly CD34(+) cells with the phenotype of myeloid precursors were mobilized. A minority of CD34(+) cells expressed the erythroid and megakaryocytic lineage-associated antigens and ct low but distinct population of CD34(+) cells expressed antigens associated with multipotent stem cells. Analysis showed that the number of CD34(+)CD33(-) cells (r = -.74, P < .05), as well as the number of CD34(+)CD41(+) cells (r = -.81, P < .005), correlated significantly better with time to neutrophil and platelet recovery, respectively, than with the total number of CD34(+) cells (r = -.55 and r = -.56, respectively). Conclusion: The numbers of CD34(+)CD33(-) cells and CD34(+)CD41(+) cells may help to predict short-term repopulation capacity of pBSCs, especially when relatively low numbers of CD34(+) cells per kilogram are reinfused. J Clin Oncol 13:1922-1932. (C) 1995 by American Society of Clinical Oncology.