Comparative study of two cytofluorometric methods of analysis

Cytofluorometry of lymphocytes is an important technique in experimental bi ology and clinical medicine. One source of variability in the results with this technique stems from the difficulty of delineating cell subpopulations on a visual basis. We have evaluated the performance of a novel software m ethod (Attractor), which introduces cluster analysis for the more precise d efinition of cell populations. Using 115 blood samples from patients with v arious immunological diseases, we compared the results obtained for 19 lymp hocyte cell populations employing either the Attractor program or a convent ional program (Cellquest). The analysis focused on inter-observer and inter -method variability and comparability. Inter-observer variability was signi ficantly lower with the Attractor software, particularly when quantifying s mall cell populations such as activated subsets. The results obtained with both methods showed high correlation coefficients except for some cell popu lations that were either very small or which had to be calculated from the sum of other counts. The performance of the novel flow cytometric software is similar to software programs currently in use, but it offers an advantag e for the definition of small and/or activated lymphocyte subpopulations. M oreover, the consistency of the measurements is better. A major disadvantag e for statistical analysis, however, is that the Attractor program has not been adapted for non-parametric data. (C) 2000 Elsevier Science B.V. All ri ghts reserved.