Phenotypic characterization of mononuclear white cells using finger-prick blood and light microscopy

A technique for the enumeration of T cell subsets in capillary blood for use in the field is described. Mononuclear white cells were separated from 0.4 ml capillary blood, kept covered by culture medium on a Multitest slide, and incubated with monoclonal antibodies to the CD2, CD4, CD8, and interleukin-2 receptor antigens. Secondary and tertiary alkaline phosphatase conjugates were used for labeling. The substrate gave a distinct blue surface staining to the positive lymphocytes. Comparison was made with a conventional immunofluorescent antibody technique (r = 0.95).