Neutrophils of healthy aged humans are normal

Polymorphonuclear functions are reported to be altered in aged humans. We have previously shown that chemotactic response, adherence, oxidative metabolism and Candida killing activity were abnormal in subjects over 70 years. These results lead us to investigate further the basic mechanisms of these alterations in a complementary series of elderly people over 75 years. However, we used in the present study the admission criteria of the SENIEUR protocol specially designed for immunogerontological investigations in humans. Neither the tests exploring the functions as a whole (migration and bacterial killing) nor those investigating the elementary components of these functions exhibited significant difference when compared to the sex-matched young controls. The discrepancy with our prior results is probably explained by the fact that the presently tested subjects had been selected according to more strict criteria. These data clearly demonstrate that neutrophils are intrinsically normal in the aged. Thus, it appears that the frequently observed neutrophil dysfunction in the elderly is due to the action of abnormal humoral components related to the aging process on otherwise normal neutrophils.