Background :We intended to confirm a decline in neutrophil function with aging and to devise a simple neutrophil function test protocol for use in a clinical setting. Reversely, the reliability of this protocol was to be verified by detectability of a decline in neutrophil function with aging. Method :Whole blood samples from young (thirties, N=32) and old (sixties, N=32) healthy subjects were incubated with the 7-aminoactinomycin D stained Escherichia coli. The mixture was stained by dihydrorhodamine 123 as an oxidative probe. Two kinds of fluorescence were measured by flow cytometry. Result :Phagocytosis was declined with aging as indicated by a decrease in the percentage (form 28.2±9.5% to 21.9±10.9%, P Conclusion :The devised protocol in this study could detect a significant decline in neutrophil function with aging, and this protocol may be useful for the assessment of neutrophil function in a clinical setting. (Korean J Lab Med 2005; 25: 273-9)

Keywords: Neutrophil, Phagocytosis, Oxidative burst, Aging