Systemic immune aberrations in Alzheimer's disease patients.

The role of chronic inflammation in the pathogenesis of Alzheimer's disease (AD) has been implied in a plethora of studies. The objective of the present study was to evaluate the immune alterations and the immunological markers in patients suffering from AD. IL-1alpha, IL-2, IL-6, IL-8, IL-10, TNF-alpha cytokine and helper/inducer (CD4), suppressor/cytotoxic (CD8) T lymphocyte levels were investigated in patients with various degrees of cognitive impairment (mild-moderate and severe stage), as well as in age-matched non demented controls. Cytokines were measured using the ELISA immunoassay method and lymphocytes using flow cytometry. Results showed a significant TNF-alpha increase in patients of severe stage serum compared to controls as well as a significant decrease of CD4 lymphocyte subpopulation levels in patients of severe stage compared to those of mild-moderate stage patients and controls. No significant differences were observed on IL-1alpha, IL-2, IL-6, IL-8, IL-10 cytokine levels and on CD8, CD4/CD8 lymphocyte subpopulations levels between patients and controls neither between mild moderate and severe stage patients. CD4 lymphocyte subpopulation and cytokine IL-2 were revealed as having a significant relationship (positive and negative respectively) with the MMSE score of patients. Data suggest the existence of detectable changes of peripheral immune system in AD.