Cholesterol dysregulation in peripheral blood mononuclear cells of Alzheimer's disease.

Cholesterol and the immune system are involved in Alzheimer's Disease (AD). To investigate the relations among them, we compared the cholesterol content in peripheral blood mononuclear cells (PBMC) of cognitively healthy controls and patients with mild cognitive impairment (MCI) and AD in two independent samples. Free cholesterol content of PBMC was lower in MCI and AD patients, and was modulated by APOE genotype. A decrease of CD8+ and an increase of CD16+ was also found in AD patients. These results suggest that cholesterol levels in PBMCs may represent an early signature of the disease and support the involvement of immune system in AD.