Abstract
Elderly persons have a tendency to be easily infected by various opportunistic pathogens. However, the reasons are still unclear. Therefore, we tried to elucidate the differences in function of peripheral blood neutrophils between elderly and young adults. There was no significant difference in their leukocyte counts. However, we found there were clear differences in the production of reactive oxygen intermediates by purified neutrophils between them. That is, those of elderly persons (over 70, av. 76.3 years old) produced only one third amount of hydrogen peroxide, and only one 10th of superoxide by young adults (av. 23.2 y.o.). Furthermore, Pseudomonas aeruginosa grew in the neutrophils of every elderly person, but not in those of any young ones. These results indicated that lower capability of neutrophils on the production of reactive oxygen intermediates would be a reason for the compromised state of elderly persons.
