Previous studies have shown that a distinctive pattern of
acid alpha-naphthyl acetate esterase (
ANAE) activity (focal reaction product) characterizes normal human peripheral blood and tissue T lymphocytes but is absent from thymocytes and certain
mitogen-stimulated T-cell blasts. In the present study mononuclear cell
suspensions prepared from the peripheral blood and tissue specimens of 35 patients with lymphoid
malignancies were simultaneously analyzed for
surface immunoglobulin, sheep erythrocyte rosette formation,
Ia antigens, and
ANAE activity. The neoplastic cells from 16 patients with Ia+ SIg+ E- (B cell)
malignancies, 4 patients with Ia+ SIg- E- (non-B, non-T)
acute lymphoblastic leukemia, and 3 patients with Ia- SIg- E- (null cell)
malignancies failed to exhibit
ANAE activity. The neoplastic cells from 5 patients with Ia- SIg- E+ (T cell-derived)
malignancies, including three cutaneous
lymphomas, displayed characteristic T-pattern positivity, and in each case the percentage of E+ and ANAE+ cells was comparable. The neoplastic cells from 4 patients with Ia- SIg- E+ (T cell-derived)
acute lymphoblastic leukemia were
ANAE-. The expression of
ANAE activity in T cell-derived
malignancies may parallel its expression in the stages of normal T-cell differentiation and may prove to be a useful marker with which to sort out T-cell phenotypes.