Lymphomonocyte subpopulations, activation and cytokine production in Alzheimer's Disease (AD)

Abstract

AD is a neurodegenerative illness characterized by accumulation of β‐amyloid (A β‐42) and inflammation. To investigate the systemic signs of immune processes in AD we examined lymphomonocyte subpopulations (PBMCs) of 17 patients and 7 age‐matched healthy controls (HC). No differences were observed in T, B and NK subsets between the two groups, whereas an increase of both CD4+ and CD8+ naïve T cells was observed in AD patients. We analyzed AD and HC PBMCs after "in vitro" activation with Aβ‐42 and no differences were observed in the expression of early activation markers CD25 and CD69 on T and B cells, although AD cells show a basic activation. We also evaluated, on monocytes, the expression of the activation markers CD80 and HLA‐DR and of the receptor for fibrillar Aβ‐42, CD36. Here again no differences were observed between the two groups, even if there is a basic high expression of CD36 on AD cells. The evaluation of cytokines production after "in vitro" culture with Aβ‐42 shows an increased production of pro‐ and anti‐inflammatory cytokines and chemokines, in AD when compared to HC. These results, although puzzling, demonstrate an involvement of systemic immunity in AD patients.This work was supported by grants from the Italian Ministry of Education, University and Research (MIUR, ex 60%)