Cytochemistry of normal and leukaemic lymphocytes: a review

Findings with six cytochemical reactions demonstrable in normal and leukaemic lymphocytes were reviewed. The two methods which are presently of greater diagnostic value are the acid phosphatase (AP) and alpha-naphthyl acetate esterase (ANAE) reactions. AP has a definitive role in the diagnosis of acute and chronic T-cell leukaemias, where a strong positive reaction helps to distinguish them from most B-cell lymphoproliferative disorders. New findings concerning the ultrastructural localization of this enzyme are presented. ANAE is of value in distinguishing T-lymphocytes (positive localized reaction) from B lymphocytes (negative reaction) and the T micron from the T gamma subpopulation of T-lymphocytes, a positive reaction demonstrable only in the T micron cells. Other reactions reviewed were PAS, beta-glucoronidase, hexosaminidase and alkaline phosphatase.