Abnormal expression of actin in lymphocytes of Alzheimer's disease and Down's syndrome patients.

Alzheimer's disease (AD) is a degenerative disorder of the central nervous system accompanied by several immunological disturbances and a number of common features exist between AD and Down's syndrome (DS). High resolution two-dimensional electrophoresis of lymphocyte proteins demonstrates an actin abnormality in AD and DS: a double actin spot instead of the single spot observed in controls. This dual form was studied by pulse-chase experiments and seems to be related to extracellular factors which influence the post-translational modification of actin. These results agree with the immunological disturbances observed in AD and DS, and with the well established hypothesis that AD is a systemic as well as cerebral disease.