Abstract

In patients with the clinical diagnosis of Alzheimer disease (AD), we searched for systemic changes in components of the blood as a diagnostic tool. The acetylcholine-related enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were measured in plasma, erythrocytes, platelets and lymphocytes. Results did not show a general effect; notwithstanding, specific cell types presented alterations either in AChE or BuChE but not in both enzymatic activities. In AD patients, AChE of lymphocytes was reduced by 60% compared with the age-matched controls. However, when patients were divided, the sporadic but not the familial subgroup exhibited a significant reduction. In erythrocytes the BuChE activity was reduced by 45% in sporadic AD. The molecular forms of the lymphocyte AChE were characterized by velocity sedimentation. Both globular forms were subnormal, more so the tetrameric G(4) AChE form than the G(2) form.