Alterations in immune functions during normal aging and Alzheimer's disease

It is thought that aging induces immune changes, which are related to the p athophysiology of Alzheimer's disease (DAT). In this study, the total numbe r of leukocytes, white blood cell differentiation, mitogen-induced lymphocy tic proliferation, neutrophil phagocytosis and superoxide release, and pros taglandin E2 (PGE2) production by mitogen-stimulated whole blood cultures w ere comparatively investigated between healthy adults (range 22-45 years) a nd healthy elderly volunteers (range 70-91 years), and between DAT patients (range 56-94 years) and age-matched control subjects. Healthy elderly volu nteers showed significantly lower phytohemagglutinin (PHA)-induced lymphocy te proliferation and percentage and absolute number of basophils than young volunteers. In normal volunteers, there were significant and negative corr elations between age and the number of basophils. Patients with DAT showed a trend toward significantly higher PHA-induced lymphocyte proliferation an d significantly decreased percentage and absolute number of large unstained cells than healthy volunteers. In DAT patients, the total number of leukoc ytes and the percentage and number of neutrophils were positively correlate d with age. All other immune-inflammatory variables were not significantly altered either by the aging process or DAT. The present study suggests that aging and DAT may differently affect some immune variables. (C) 1999 Elsev ier Science Ireland Ltd. All rights reserved.