EXCITATORY PATTERN OF GAMMA-INTERFERON ON NATURAL-KILLER-CELL ACTIVITY IN SENILE DEMENTIA OF THE ALZHEIMER-TYPE

Spontaneous natural killer (NK) cell activity and NK-induced cytotoxic ity after interferon-gamma (IFN-gamma) were measured in healthy elderl y subjects and in patients with senile dementia of Alzheimer type (SDA T) and multi-infarct dementia (MID). Normal basal and IFN-gamma-stimul ated NK cytotoxicity were found in healthy old subjects and in patient s with MID. On the contrary higher NK cytotoxicity after IFN-gamma (65 0 IU) was demonstrated in SDAT patients than in MID and healthy subjec ts (p < 0.001). A significant inverse correlation between the percent increase of NK cytotoxicity after IFN-gamma and the Mini Mental State Examination score (p < 0.001) was also demonstrated in patients with S DAT. Our data might suggest a cytokine-dependent mechanism of NK activ ation in SDAT associated with the neuroimmune hypothesis of the diseas e.