title: Evaluation of an automated hematologyanalyzer (CELL-DYN 4000) for counting CD4+ T helper cells at low concentrations.
abstract: In human immunodeficiency virus (HIV) infection, CD4 cell counts are useful in defining the disease state, monitoring antiviral treatment, and identifying patients at risk for opportunistic infections. Counting CD4 cells typically relies on traditional immuno-flow cytometric analyzers that require opening the tube for manipulation of the blood sample. In addition to automated blood cell counting, the CELL-DYN 4000 hematology analyzer performs a completely enclosed and automated analysis of the T lymphocyte subsets. We studied the performance characteristics of this method in blood samples containing low levels of CD4+ T cells. In one set of experiments, we emulated low level CD4 counts by use of a CD4 Positive Isolation Kit to deplete the CD4+ cells from blood samples. We used the FACScan analyzer for reference counts. Measurements were made exactly 12 hr after venepuncture in samples that were stored at room temperature. In normal samples and those with low CD4+ cell counts, there was excellent correlation between the results of the CELL-DYN and FACScan methods. Using the CELL-DYN 4000 analyzer, the precision of CD4+ and CD8+ T-cell counts was high (CV = 2 to 8%). The CD4+ T-cell count was linear over a wide range (35 to 1640 cells/microl). This study shows that CD4 and CD8 T cell counts using the CELL-DYN 4000 analyzer is suitable for normal samples and also for those with low CD4+ T cell counts. The method is rapid and automated, and blood specimens remain enclosed, minimizing the biohazard of exposure to blood of HIV patients.
authors.affiliation: Clinical Hematology and Clinical Diagnostics, Graduate School of Medicine, Osaka City University, Osaka, Japan.
authors.forename: Kiyoyuki
authors.initials: K
authors.lastname: Hagihara
authors.forename: Takahisa
authors.initials: T
authors.lastname: Yamane
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Aoyama
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Nakamae
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hino
mesh_terms: D001331:Automation; D018791:CD4 Lymphocyte Count / Q000379:methods*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D006801:Humans; D018655:Lymphocyte Count / Q000379:methods; D008991:Monitoring, Physiologic / Q000379:methods; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology*