• ALDH1;
  • electronic cell volume;
  • CD34;
  • CD90;
  • CD117;
  • CD133;
  • stem cells



Over-expression of aldehyde dehydrogenase and other stem cell markers is characteristic of cells with tumorigenic potential in NOD/SCID mice. Most of these studies have focused on metastatic cells in bone marrow and on solid tumors. There are no studies on correlation of marker expression with ALDH1 expression in cells from human peripheral blood apheresis (HPC-A) samples.


HPC-A samples from 44 patients were incubated with Aldefluor® with or without the presence of aldehyde dehydrogenase inhibitor DEAB. Cells with high aldehyde dehydrogenase expression (ALDH1bright) were analyzed for stem/progenitor markers CD34, CD90, CD117, and CD133. Electronic volume measured by Coulter principal in a Quanta flow analyzer was correlated with ALDH1 and marker expression.


In ALDH1bright/SSClow cells, 0.13% of the cells had CD34+ expression and three distinct populations were seen. Expression of CD90 was dim and the frequency of ALDH1bright/SSClow/CD90dim cells amongst the nonlineage depleted samples was 0.04%. CD117dim-bright expression was seen in 0.17% of the samples. Three distinct populations of cells with CD133 expression were seen in ALDH1bright/SSClow nonlineage depleted cells with a frequency of 0.28%. The ALDH1bright/CD90dim cells had the smallest mean electronic volume of 264.9 μm3 when compared with cells with CD34bright expression (270.2 μm3) and ALDH1dim/CD90dim cells (223 μm3).


ALDH1bright/SSClow cells show heterogeneity in expression of the four stem cell markers studied. The CD90 cells in both the ALDH1bright and ALDH1dim populations had the smallest mean electronic volume when compared with similar cells with CD117 expression. © 2010 Clinical Cytometry Society