DISCORDANT NEUTROPHIL ALKALINE-PHOSPHATASE ACTIVITY AND CYTOGENETIC RESPONSE IN CHRONIC MYELOID-LEUKEMIA TREATED WITH ALPHA-INTERFERON

Decreased neutrophil alkaline phosphatase (NAP) synthesis is a classic al feature of Philadelphia (Ph) positive chronic phase chronic myeloid leukemia (CML). Whether this aberration is an integral leukemic prope rty of the cell or results from mediation by other factors is unclear. During alpha-interferon (alpha-IFN) based therapy the relationship be tween Ph chromosome suppression and NAP synthesis was examined. Four c ategories of response were observed in 19 patients studied sequentiall y. Significantly, persistent low NAP activity was observed in one pati ent in complete cytogenetic remission, while a second group of 7 patie nts demonstrated normal NAP activity in spite of persistence of the Ph chromosome in 100% of metaphases. In the absence of various clinical influences that can modulate NAP activity in chronic phase CML, the re sults reinforce the observation that the BCR/ABL fusion gene product i s not a key factor influencing NAP activity in CML.