The discrepancy between chemotaxis and leukotriene B4 production in a patient with chronic neutrophilic leukemia

Chronic neutrophilic leukemia (CNL) is a rare type of leukemia. We diagnosed a 81-year-old woman as CNL because she showed that sustained leukocytosis dominated by mature neutrophils, hepatosplenomegaly, high neutrophilic alkaline phosphatase (NAP) score, absence of the Ph1 chromosome and no evidence of leukemoid reaction. During the clinical course, she did not manifest hemorrhagic tendency or infection. We also examined neutrophilic function including chemotaxis, chemiluminescence, nitroblue tetrazolium (NBT) dye reduction, which all indicated normal neutrophil function. Using a reversed phase-high pressure liquid chromatography (HPLC), we detected the production of leukotriene B4 (LTB4) in neutrophils. We found that the LTB4 production was decreased in neutrophils whereas they showed normal chemotaxis. This discrepancy has never, to our knowledge, been reported before in case of CNL.