Analysis of CD4+ and CD8+ T-lymphocytes : A comparison between EPICS XL and Celldyn Sapphire

Flowcytometric technology has been widely used for measurement of the absolute numbers of T-lymphocytes subsets in Human Immunodeficiency virus (HIV), defining the disease state, monitoring antiviral treatment, and identifying any risk for opportunistic infections. A manual preparing of the samples is required. More recently an automated and enclosed blood cell counting, Celldyn Sapphire has been introduced. In this study the performance of the Flow cytometer EPICS XL as a reference method for analysis of CD3+, CD4+ and CD8 T-lymphocytes was evaluated with blood from 40 individual’s samples. EPICS XL was also compared with Celldyn Sapphire in the analysis of T-lymphocyte subsets in 39 blood samples from patients with low, high and normal lymphocyte counts. The result showed that the precision was high for both EPICS XL (2.5%) and Celldyn (10%). The method was linear over a wide range. Comparisons of CD3+, CD4+, and CD8+ T-lymphocytes analysis showed high coefficients of correlation (r0.9) and agreement (y>0.9x) between two instruments. A lower degree of agreement was observed at low concentration of CD3+ and CD4+ T-lymphocytes (0.757, 0.739). This means that cell counts obtained by Celldyn were 30% lower than those obtained with EPICS XL. This study shows that both EPICS XL and Celldyn Sapphire were suitable for CD4+ and CD8+ T cell counts. It is however preferable to use Flowcytometry for counting of low concentration of CD4+ T-lymphocytes (<200 cells/µL)