Functional Decline in Human Neutrophils with Age

. The neutrophil forms the first line of defence against rapidly dividing bacteria and fungi. As humans age they become more susceptible to infection by these microbes (1). We have investigated the neutrophil functions affected by ageing in humans and examined the underlying mechanisms resulting in the age related decline in function. We have observed a reduction in cell surface expression of the Fc receptor CD16, accompanied by a decrease in the phagocytic ability of neutrophils from elderly individuals. In elderly patients with neutrophilia, in which the fraction of blood neutrophils recently released from the bone marrow is increased, CD16 was not significantly increased. These data suggest that in the elderly neutrophils are released from the bone marrow with compromised function, indicative of a defect in progenitor cell production.