Altered lymphocyte acetylcholinesterase activity in patients with senile dementia.

Reductions in the acetylcholinesterase (AChE) activity of certain brain areas in patients with senile dementia of Alzheimer type (SDAT) have been found to correlate with the severity of the disease, suggesting a central cholinergic lesion. Since AChE is expressed on the surface of various blood cells too, the AChE activity of lymphocytes and erythrocytes was determined to test the possibility whether the cholinergic lesion is also reflected on these readily available cells. The AChE activity of lymphocytes in SDAT and in alcoholic dementia (AD) were significantly lower as compared to those of the age-matched healthy volunteers. In contrast, there was no significant difference in the activity of lymphocyte AChE between age-matched healthy controls and patients with multi-infarct dementia of vascular origin (MID). No changes could be demonstrated in the erythrocyte AChE activities of the patients studied, and the age-matched healthy individuals, when comparing them to the healthy blood donors. The AChE activity of lymphocytes may thus be a useful marker to follow the alterations in the metabolism of acetylcholine (ACh) in the central nervous system (CNS) of different types of dementia.