DIFFERENCES IN DEXAMETHASONE-SENSITIVITY BETWEEN LYMPHOCYTES FROM PATIENTS WITH ALZHEIMERS-DISEASE AND PATIENTS WITH MULTIINFARCT DEMENTIA

Peripheral blood mononuclear cells (PBMC) from 40 consecutive patients entering a screening program on cognitive impairment were studied in vitro with respect to their sensitivity to dexamethasone (DEX). Phytoh emagglutinin-induced proliferation by PBMC from patients with senile d ementia of the Alzheimer type (SDAT) was less sensitive to the inhibit ory effect of DEX, compared to PBMC from patients with multi-infarct d ementia (MID) and PBMC from patients with miscellaneous causes of cogn itive impairment (MISC). An intermediate sensitivity was found with PB MC from patients with clinical signs of both MID and SDAT (= MIXED). T hese differences could not be explained by differences in the composit ion of the CD4(+) T cell population, interleukin (IL)-2 or IL-4 produc tion, or quantitative differences in the expression of glucocorticoid receptors as measured by flowcytometry. However, the expression of bcl -2 was higher in PBMC from SDAT patients than in cells from MID patien ts or from MISC patients, whereas the MIXED group showed an intermedia te expression; a high bcl-2 expression correlated with a low DEX-sensi tivity. These findings suggest that characteristics of PBMC reflect re lated changes in the central nervous system and indicate that PBMC may be a useful and accessible tool to obtain more insight into the patho genesis of Alzheimer's disease. (C) 1996 Academic Press, Inc.