Discordant results of flow cytometric ZAP-70 expression status in B-CLL samples if different gating strategies are applied
✍ Scribed by Christian Wilhelm; Andreas Neubauer; Cornelia Brendel
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 478 KB
- Volume
- 70B
- Category
- Article
- ISSN
- 1552-4949
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Background:
Recent studies have identified ZAP‐70 expression status as an excellent prognostic parameter in chronic lymphocytic leukemia (CLL). ZAP‐70 expression can be determined by direct antibody staining followed by flow cytometric analysis. However, there are currently several different gating strategies for analysis. We compared those strategies for ZAP‐70 expression analysis.
Methods:
One hundred and one patients with B‐CLL were analyzed employing a directly labeled alexa‐fluor‐488‐ZAP‐70‐antibody. In 27 cases, we additionally measured and analyzed ZAP‐70 expression, together with healthy controls as described previously.
Results:
Applying either T‐/NK‐cell isotype or healthy control analysis strategies on patient samples that were processed in parallel revealed discrepant results in 48% (12/25) of all cases. Taken together with the 74 B‐CLL patients, who were analyzed with regard to average reference values, disconcordant results were obtained in 58% of the samples. We demonstrate that high variances in ZAP‐70 T‐/NK‐cell staining within B‐CLL patients, paired with a close proximity of ZAP‐70 B‐cell values to the suggested cut‐off levels, may lead to interpretation difficulties of ZAP‐70 status.
Conclusions:
We conclude that different gating strategies for determining flow cytometric ZAP‐70 expression status produce highly discordant results. Further standardization is required before ZAP‐70 can be used as a reliable prognostic parameter in immunophenotyping of B‐CLL. © 2006 International Society for Analytical Cytology