THE USE OF THE APAAP TECHNIQUE AS A RAPID INDICATOR OF PERIPHERAL-BLOOD PROGENITOR-CELL LEVELS

Rapid and sustained engraftment following autotransplantation with per ipheral blood stem cells (PBSC) depends on adequate numbers of stem ce lls and progenitor cells. In this study we have compared the number of myeloid progenitor cells quantitated using the colony forming units-g ranulocyte macrophage (CFU-GM) clonogenic assay with the number of CD3 4+ cells estimated both by flow cytometry and by the alkaline phosphat ase anti-alkaline phosphatase (APAAP) technique. We have analysed 15 p eripheral blood mononuclear cells (PBMNC) samples from 13 normal subje cts and 179 PBMNC from 32 patients undergoing PBSC harvests during the recovery phase of high dose cyclophosphamide chemotheraphy. The numbe r of CD34+ cells measured by the APAAP technique correlated well with the number of CD34+ cells measured by flow cytometry (r = 0.727, p = 0 .0001), and also with the number of CFU-GM measured in the clonogenic assay (r = 0.721, p = 0.0001). The APAAP method provides a rapid, reli able measure of progenitor cell levels that can be used to monitor the optimal time to harvest peripheral blood stem cells (PBSC), and to es timate the marrow repopulating ability (MRA) of stem cell preparations used for transplantation.