Acid α-naphthyl acetate esterase (ANAE) in human B cells: Correlation of expression with stages of B-cell differentiation

Abstract

Normal and malignant cells of the B cell lineage were examined for their expression of acid α-naphthyl acetate esterase (ANAE) and correlation of ANAE expression with cytoplasmic immunoglobulin (CIg), a marker which defines plasma cells. Resting peripheral blood B cells are ANAE −. In contrast, the majority, but not all, benign plasma cells and the malignant plasma cells of Waldenstrom's macroglobulinemia and multiple myeloma express ANAE in a distinctive staining pattern, i.e., multiple, variably sized nodules of reaction product in the paranuclear Golgi zone, which is distinguishable from that of monocytes and T cells. A variable proportion of pokeweed mitogen-stimulated B cells and the cells in each of three immunoglobulin-secreting B cell lines also expressed ANAE. In these instances the percentage ANAE + cells exceeded the percentage CIg + cells. A variable proportion of the neoplastic cells, 21–76%. in 4 of 25 cases of B-chronic lymphocyte leukemia (CLL) unassociated with monoclonal serum proteins and 2 of 4 cases associated with monoclonal serum protein production expressed ANAE in a staining pattern similar to that of plasma cells but with weaker intensity. B-CLL and plasma cell ANAE activity was inhibited by sodium fluoride, similar to monocyte and dissimilar from T cell ANAE activity. The malignant cells of acute myelogenous and lymphoblastic leukemia were ANAE −. These findings suggest that B cells express ANAE as they differentiate into plasma cells and/or are activated. Moreover, variable ANAE expression is another example of inter- and intratumor heterogeneity displayed by certain B cell malignancies.