The bone marrow plasma cell labeling index by flow cytometry

✍ Scribed by Belinda Pope; Ross Brown; John Gibson; Doug Joshua

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 213 KB
• Volume: 38
• Category: Article
• ISSN: 0196-4763
• DOI: 10.1002/(sici)1097-0320(19991215)38:6<286::aid-cyto5>3.0.co;2-7

✦ Synopsis

The bone marrow plasma cell labeling index is the most important prognostic indicator for patients with multiple myeloma. Traditionally, this test has been performed as a two color immunofluorescent microscope technique which is time consuming and requires a degree of subjectivity in its interpretation. We have assessed various adaptations of this method to flow cytometry. A bromodeoxyuridine method has been compared with a propidium iodide DNA method to detect cells in S phase and CD38-FITC has been compared with CD38-FITC ؉ CD138-FITC and CD38-biotin ؉ streptavidin FITC to identify plasma cells. The mean channel fluorescent intensity of the plasma cell peaks for each of these markers was 12.7, 17.4 and 35.3 respectively demonstrating the superiority of CD38-biotin ؉ streptavidin FITC. Analysis after propidium iodide staining provided a good correlation with the slide technique (r ‫؍‬ 0.71; P F 0.0001) but the bromodeoxyuridine method did not correlate with the slide method (r ‫؍‬ 0.09; P ‫؍‬ NS). The labeling index values obtained from either of the flow methods were greater than the microscopic method. Thus a labeling index of G4% will replace the traditional G1% threshold for identifying patients with a significantly increased labeling index. The advantages of the new method are that it takes less time to perform, is more objective and provides additional data on ploidy and cell cycle status.