Enhanced Cytotoxic Response of Natural Killer Cells to lnterleukin-2 in Alzheimer's Disease

Abstract

Experimental data suggest an involvement of immune cellular components in the development of Alzheimer''s disease (AD). Against this background, the spontaneous natural killer (NK) cell activity and the NK-induced cytotoxicity after interleukin-2 (IL-2) were studied in healthy elderly subjects and in patients with dementia of Alzheimer type (SDAT) and multi-infarct type (MID). Higher NK cytotoxicity (expressed as total lysis and percent increase) at different IL-2 concentrations (50 and 100 IU/ml/cells) was demonstrated in patients with SDAT than in healthy elderly subjects (p < 0.001) and MID patients (p < 0.001). NK cell activity of MID patients was similar to that of healthy elderly and healthy young subjects. A negative correlation between the percent increase in NK cytotoxicity after IL-2 and the Mini Mental State Examination Score was also found in SDAT patients (p < 0.01). Alterations of IL-2-mediated NK cytotoxicity may therefore support the neuroimmune hypothesis of AD.