Flow cytometric chemosensitivity analysis of blasts from patients with acute myeloblastic leukemia and myelodysplastic syndromes: The use of 7AAD with antibodies to CD45 or CD34
✍ Scribed by M. Pallis; J. Syan; N.H. Russell
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 283 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0196-4763
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✦ Synopsis
Background: Flow cytometry is potentially suited to the chemosensitivity analysis of peripheral blood or bone marrow subpopulations in patients with leukaemia and myelodysplastic syndromes. Methods: The use of the fluorescent dye 7-aminoactinomycin (7AAD) on unfixed cells to measure loss of viability at a range of cytosine arabinoside (ara-C) doses was evaluated. A six-tube flow cytometric assay for measuring the sensitivity to ara-C of CD45/side-scatter-gated or of CD34-positive leukemic blasts with 7AAD was established, using fixed stained normal mononuclear cells as an internal standard for quantitation of viable cells following culture. Results: 7AAD dose response curves for 10 patients with acute myeloblastic leukemia (AML) showed a wide range of sensitivities at 2.5-5 µM araC (3.7-97%, mean 54% of control cell viability at 2.5 µM and 4.1-94.6 %, mean 27% at 5 µM). Parallel assays for ATP bioluminescence agreed reasonably well with the 7AAD method, r s ϭ 0.78. The chemosensitivity of CD45/SSC-gated blast cells at 2.5 µM araC showed no consistent relationship with the ungated cell populations, such that CD45/SSC-gated blast sensitivity of seven samples ranged from 86% more to 38% less than that of the total population. Similarly, the chemosensitivities of the CD34-gated subpopulations ranged from 51% more to 78% less than those of the total populations. Conclusions: These results emphasize the necessity of measuring the chemosensitivity of the population of interest rather than of the sample as a whole in heterogeneous clinical material.