Abstract

The findings of recent surveys indicate a need for standardisation in lymphocyte subset analysis by flow cytometry. Major areas of concern are the methods used for labelling subsets and the choice of appropriate monoclonal antibodies. A standard dual colour manual whole blood lysis technique for flow cytometry was compared with the recently available Coulter Q-Prep EPICS technique. Overall, there was no significant difference (Student's t test) between the use of anticoagulated blood treated with heparin or EDTA. When normal subjects were examined there was a decrease in the absolute number of CD3+ and Leu-7+/CD8- cells and an increase in CD19+ and CD20+ cells. When human immunodeficiency virus (HIV) antibody positive subjects were examined there was a significant decrease in the absolute number of CD2+, CD3+, CD4+ and Leu 7+/CD8- cells and an absolute increase in CD19+ and CD20+ cells. CD8+ cells were decreased only with the Cyto-Stat reagents. Occasionally, the Q-Prep did not lyse the red cells efficiently. While the Q-Prep EPICS system has the potential to standardise and automate the labelling procedures used in lymphocyte subset analysis, further refinement, such as the choice of monoclonal antibodies or alternative preparative reagents, may be required to resolve the cause of the discordant findings between the two approaches.