Reliability of alpha-naphthyl-acetate esterase staining of blood smears for the enumeration of circulating human T lymphocytes

Cytocentrifuged preparations of glutaraldehyde-fixed E rosettes were stained for acid alpha-naphthyl-acetate esterase activity (ANAE). On average, 84% of the rosette-forming cells (E ⁺) also stained positively for the enzyme activity (A ⁺). ANAE staining of blood smears of thirty-three healthy controls was compared to E rosetting by a conventional method. A ⁺ and E ⁺ fractional values are highly significantly correlated; the regression of E ⁺ on A ⁺ is E ⁺ fractional values are highly significantly correlated; the regression of E ⁺ on A ⁺ is E ⁺ = 0.805.A ⁺ + 16.8 (P <10 ^-6). Since the correlation between E ⁺ and A ⁺ cells is both statistically and cytologically significant, we propose blood smear ANAE staining as a simple and convenient method to enumerate circulating T lymphocytes in clinical practice.