[System of natural killer lymphocytes in Alzheimer's type dementias]

Cytotoxic activity and quantity of natural killer (NK) lymphocytes were measured in 25 patients with Alzheimer's disease (AD), in 13 patients with senile dementia of Alzheimer's type (SDAT) and in 31 normals of different age (controls). In mentally healthy elderly individuals of the same age as the patients, functional activity of a subpopulation of NK lymphocytes was significantly decreased in comparison with healthy young people, meanwhile a number of these cells wasn't changed. In patients with AD and SDAT the tendency was found to increasing of functional activity of NK lymphocytes in comparison with elderly normals, which achieved the degree of significant differences only in SDAT patients with moderate dementia. Direct dependence of cytotoxic activity of NK lymphocytes on AD duration was determined. Such correlation was not observed in SDAT. This permitted to suppose a destructive influence of lymphocytes with increased cytotoxic activity on either CNS cells or their components in AD.