Age-related changes of apoptotic cell death in human lymphocytes

Apoptosis seems to be involved in immunosenescence associated with aging. M oreover, in lymphocytes (PBL) of patients with Alzheimer's disease, an incr eased susceptibility to the apoptotic pathway has been described possibly d ue to impaired protection of oxidative stress. Accordingly, it seemed to be of particular interest to investigate the contribution of normal aging to the susceptibility from human lymphocytes to programmed cell death. We coul d show that PBL from elderly individuals (>60 years) accumulate apoptosing cells to a significant higher extent in spontaneous and activation-induced cell death compared to younger controls (<35 years). Treatment with the oxi dative stressor 2-deoxy-D-ribose or with agonistic-CD95-antibody pronounced this effect even more implicating a higher sensitivity to reactive oxygen species and a higher functional CD95 expression, respectively. In addition, expression of the activation markers HLA-DR and CD95 was significantly inc reased in CD3(+)-cells of aged subjects, while expression of CD25 did not s eem to be affected by age. Expression of Bcl-2 was increased in aging and c orrelated with the number of apoptotic cells. (C) 2000 Elsevier Science Inc . All rights reserved.