Senile dementia of Alzheimer's type (SDAT): reduced T8+-cell-mediated suppressor activity.

We compared patients with senile dementia of the Alzheimer's type (SDAT) and age-matched controls with respect to T8+-cell-mediated suppressor function using a pokeweed mitogen (pwm)-induced IgG secretion assay. The responding B cells were allogeneic to the T-regulator cells. T8+-cell-mediated suppression was lower in SDAT patients than the controls when we used either 2 X 10(4) or 5 X 10(4) T8+ cells. Suppressor function was lower in both SDAT and elderly controls than in young adults. SDAT patients and controls did not differ with regard to T4+-cell-mediated helper activity. In SDAT patients, there seems to be an exaggeration of the age-related decline in suppressor-cell function. Whether such changes reflect accelerated changes of intrinsic lymphocyte properties or aberrant neural influences on lymphocytes remains to be resolved.