[Changes in the immunological parameters in Alzheimer's disease: their relation to disease severity]

The peculiarities of the immune system in patients with Alzheimer's dementia (AD) and their relations with some clinical parameters were investigated. 21 patients with AD aged 51-70 and 16 age-matched healthy subjects were included in this study. The following parameters were examined: 1) total lymphocyte numbers, 2) the functional activity of T- and B-lymphocytes under conditions of stimulation by nonspecific mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM) and 3) the production of interleukin-1 (IL-1) and interleukin-2 (IL-2). A statistically significant decrease (p < 0.01) in lymphocyte number and significant increase of proliferative activity of T-lymphocytes, stimulated by PHA (when the small mitogen doses in the range of 1.25-2.5 mg/ml were used) were found in patients with moderate and severe dementia (p < 0.05, p < 0.01). No significant changes of lymphocyte proliferative activity were detected in patients with mild dementia. Some tendency for higher IL-1 production was found in AD patients, but it was not statistically significant. No changes of functional activity of B-cells and of production of IL-2 in AD patients were found in comparison with the control group.