Pattern of leukocyte acid phosphatase reaction in T-cell lymphoblastic leukemia

ABSTRACT

Acid phosphatase [AP] reaction is a specific cytochemical marker for T-cell lymphoblastic leukaemia [T-ALL]. Twenty six cases of ALL were diagnosed as T-ALL employing cytochemical profiles including AP and sheep red blood cell rosettes. Three distinct patterns of AP reaction were observed. On one end of the spectrum, 100% of the positive blasts showed the classical dot- like reaction while on the other 100% showed a scattered reaction. Between the two a mixed pattern was observed with 30- 80% of the positive blasts showing the dot-like reaction while the rest showed scattered pattern. Dot-like pattern showed L[1] morphology, high counts and low SRBC rosettes while scattered showed L[2] morphology, low counts and high SRBC rosettes. The pattern observed in our series differs from the dot-like reaction observed in T-ALL in the western series. We recommend that this pattern must be borne in mind when employing AP reaction for T- ALL diagnosis