Monocyte function in ageing humans

Peripheral blood monocytes from hospitalised patients greater than 60 years of age and less than 35 years, and those from healthy normal controls less than 35 years, were tested for a range of functional and physiological properties, comprising chemotaxis under agarose, the ability to phagocytose and kill Candida albicans, adhesion to glass and spreading on glass. No significant difference was found between young and old groups, nor between hospitalized and non-hospitalized groups in respect of any parameter. There was some decline in phagocytosis and in spreading in a very old subgroup (greater than 75 years), but this was not statistically significant. This study showed that phagocytic cell function in the elderly does not decline at the same rate as the specific immune response and thus cannot directly account for the increased incidence of infection in the aged.