Ultrastructural localization of 2-naphthylthiol acetate nonspecific esterase in human blood cells and leukemic cells.

Nonspecific esterase activity was localized ultrastructurally within normal and leukemic hematopoietic cells by the use of 2-naphthylthiol acetate (NTA) as a substrate. NTA esterase activity was identified in all cell lines, although mononuclear phagocytes contained the most abundant activity. Monocytes, macrophages, young granulocytes, eosinophils, basophils, megakaryocytes, and platelets showed reaction products primarily associated with the membranes of cell granules, mitochondria, rough endoplasmic reticulum, and perinuclear cisternae. Lymphocytes demonstrated focal uneven staining in perinuclear cisternae and endoplasmic reticulum, with only occasional cytoplasmic reactions. Erythroblasts showed the most distinctive staining pattern with predominance of large amounts of reaction product within the perinuclear space in a ring-like distribution. Examination of the staining pattern in 42 cases of leukemia and 2 cases of malignant lymphoma demonstrated only limited usefulness as a diagnostic aid.