ENUMERATION OF CD34-POSITIVE HEMATOPOIETIC PROGENITOR CELLS BY FLOW-CYTOMETRY - COMPARISON OF A VOLUMETRIC ASSAY AND THE ISHAGE GATING STRATEGY

In order to optimize peripheral blood stem cell (PBSC) collection for transplantation, absolute CD34 counts are necessary to determine the e xact time-point for sufficient leukapheresis. In an effort to establis h and to validate a rapid and reproducible assay for PBSC enumeration, different recommendations for selection of monoclonal antibodies, lys is techniques, analysis parameters and gating strategies were develope d. In this methodical study, two gating strategies for PBSC enumeratio n were compared, in order to validate the accuracy of PBSC counting in peripheral blood and apheresis products, Gating strategy I was perfor med using volumetric how cytometry and reference beads whereas gating strategy II was done according to the ISHAGE guidelines. The highly st andardized volumetric assay seems to be superior to the more 'expert-r eliant' ISHAGE procedure requiring more 'manual work' by the cytometri st.