Prediction of Engraftment After Autologous Peripheral Blood Progenitor Cell Transplantation: CD34, Colony-forming Unit-granulocyte-macrophage, or Both?

Background: The rate of hematologic recovery after peripheral blood progenitor cell (PBPC) transplantation is influenced by the dose of progenitor cells. Enumeration of cells that express CD34+ on their surface is the most frequently used method to determine progenitor cell dose. In vitro growth of myeloid progenitor cells (colony-forming unit-granulocyte-macrophage [CFU-GM]) requires more time and resources, but may add predictive information.

Study Design And Methods: A series of 323 patients, who underwent autologous PBPC transplantation for multiple myeloma, malignant lymphoma, or locally advanced breast cancer, were studied for the effect of CD34+ dose and CFU-GM dose on hematologic recovery. Measures for engraftment were days to absolute granulocyte and platelet (PLT) counts to greater than 500 per muL and than 20 x 10(9) per L, respectively, and number of PLT transfusions and red cell units required.

Results: The CD34+ dose had a median of 8.4 x 10(6) per kg, and the CFU-GM dose a median of 84.9 x 10(4) per kg. The CD34+ and CFU-GM doses showed significant correlation (R = 0.63; p < 0.0001) but a wide variation in the ratio of CD34+ and CFU-GM. Both CD34+ and CFU-GM doses had significant correlation with the measures of engraftment, but for all measures the relationship of CD34+ was stronger. Multivariate analysis and subgroup analysis of patients receiving CD34+ doses of less than 5 x 10(6) per kg also did not reveal an independent predictive value for CFU-GM.

Conclusion: For prediction of hematologic recovery after autologous PBPC transplantation, determination of CFU-GM dose does not add to the predictive value of the CD34+ dose.