CD34 Enumeration, How and When 2011
Organized by the ISCT Lab Practices
Chair and Speaker: Varda
Deutsch, PhD, Hematology Laboratory Director, Tel-Aviv Sourasky Medical
Speaker: Frank Preijers, PhD,
Stem Cell Laboratory Director/Head section Immunophenotyping, Radboud University
Nijmegen Medical Center
CD34+ cell enumeration to assess the quality of stem cell transplants is
still a subject for improvement. Although the CV values in different external
quality assessment schemes of CD34 are decreasing during the last decade, as a
result of standardization and education as well as better reagents and flow
cytometers, in many stem cell laboratories this technique still needs attention.
Generally, the determination of the number of CD34+ cells in fresh cell sources
can be performed reliably. Yet there are differences using different reagents.
The results are often worse in samples after cryopreservation and in samples
with less than optimal viability. Mainly in these determinations the enumeration
assay needs improvement. Therefore the applied methods, the used CD34 antibodies
and fluorochromes, the gating procedure (especially the sequential back gating
on CD45), the right use of 7-AAD when and application of the counting beads may
introduce deviations. Additionally, the flow cytometer used as well as the
calibration of lasers and PMTs, and the compensation of spectral overlap between
fluorochromes may influence strongly the outcome of the determinations. The most
important parameters and issues that will influence the final CD34 count will be
- Review methods and guidance documents for CD 34 enumeration in grafts.
- Discuss reagents, gating, viability testing, fluorochromes and overlap
between fluorochromes, calibration of lasers and problematic samples.
- Emphasize the most important issues that influence the final CD34+ cell
This product is a downloadable PDF containing a link to the mp4 video recording of this presentation featuring the Power Point slides and audio recording.