Age-associated changes of neutrophil responsiveness in a human healthy elderly population

Conflicting results have been reported on polymorphonuclear (PMN) cell responsiveness during senescence. Consequently, neutrophil absolute numbers and PMN-mediated chemotaxis, phagocytosis, killing and superoxide anion (O2-) generation in healthy aged volunteers divided into different groups according to increasing age criteria, were investigated and evaluated. Data provide evidence that absolute amounts of PMN cells declined in a significant manner in donors over 85 years old only when compared with young subjects. On the contrary, regardless of age, the aged individuals exhibited a significant impairment of PMN chemotactic, phagocytic and killing functional capacities. Finally, formyl-methionyl-leucyl-phenylanaline (FMLP)-triggered O2- release was reduced in all elderly groups, while depression of O2- production was seen in subjects between the age of 86 and 104 years using phorbol 12-myristate 13-acetate (PMA) as agonist. These findings indicate that an imbalance in the PMN cell immune reactivity occurs throughout the senescence process.