Esterase activity in erythroleukemia.

Specific esterase activity, a property generally ascribed to cells of granulocytic origin, was found in abnormal erythroid precursors obtained from the bone marrows of six patients with untreated erythroleukemia. These erythroblasts also showed nonspecific esterase activity. Neither specific nor nonspecific esterase activity was detected in erythroid precursors obtained from the bone marrows of ten presumed normal individuals. The implications of finding specific esterase activity in the erythroblasts of erythroleukemia are discussed.