System of natural killer lymphocytes in Alzheimer's type dementias

Cytotoxic activity and quantity of natural killer (NK) lymphocytes were mea sured in 25 patients with Altzheimer's disease (AD), in 13 patients with se nile dementia of Altzheimer's type (SDAT) and in 31 normals of different ag e (controls). In mentally healthy elderly individuals of the same age as th e patients, functional activity of a subpopulation of NK lymphocytes was si gnificantly decreased in comparison with healthy young people, meanwhile a number of these cells wasn't changed. In patients with AD and SDAT the tend ency was found to increasing of functional activity of NK lymphocytes in co mparison with elderly normals, which achieved the degree of significant dif ferences only in SDAT patients with moderate dementia. Direct dependence of cytotoxic activity of NK lymphocytes on AD duration was determined. Such c orrelation was not observed in SDAT. This permitted to suppose a destructiv e influence of lymphocytes with increased cytotoxic activity on either CNS cells or their components in AD.