Failure to achieve a threshold dose of CD34+CD110+ progenitor cells in the graft predicts delayed platelet engraftment after autologous stem cell transplantation for multiple myeloma.

To predict platelet engraftment more accurately post autologous stem cell transplantation (SCT), we retrospectively analyzed the CD34(+)CD110(+) (CD110 or c-mpl, thrombopoietin receptor) content in the grafts of 70 patients undergoing transplantation for multiple myeloma (MM) with an in-house flow cytometric assay. We found that infusing at least 3.0 x 10(4) CD34(+)CD110(+) cells/kg clearly separated the cohort into those who achieved platelet engraftment before or after 21 days.