A Rapid Method for Determining T Lymphocyte Levels Using Acid Alpha-Naphthyl Acetate Esterase

A method for rapidly determining levels of T lymphocytes in humans is presented. The method involves staining lymphocytes in peripheral blood or buffy coat smears for acid alpha-naphthylacetate esterase for 1 hr at 37 C. After counterstaining with Wright's stain, the percentage of esterase positive cells is quantitated microscopically. The entire procedure takes less than 2 hours. Data are presented which show that the percentage of esterase-positive lymphocytes accurately reflects the percentage of lymphocytes forming E rosettes with sheep erythrocytes.