Decreased sensitivity to dexamethasone in lymphocytes from patients with Alzheimer's disease.
Nijhuis E., Hinloopen B., van Duijn C., Hofman A., Rozing J., Nagelkerken L.
Cortisol levels in patients with Alzheimer's disease (AD) are relatively unaffected by a challenge with dexamethasone (DEX) in vivo. The present study demonstrates that DEX is less inhibitory for phytohemagglutinin (PHA)-induced T cell proliferation in AD patients as compared to age-matched controls. Since no significant differences were found between AD patients and age-matched controls with regard to the fraction of CD45RA+ or CD45RO+ CD4+ T cells nor the ability of peripheral blood mononuclear cells to produce IL-2 or IL-4, it is unlikely that the difference in DEX sensitivity is due to a changed lymphokine profile or a changed composition of the CD4+ T cell population. Sensitivity to DEX was negatively correlated with the ability to produce IL-2 and IL-4 in the controls but not in AD patients. This suggests that IL-2 and IL-4 synthesis in AD patients is less sensitive to regulation by glucocorticoids.