Adenosine A2A Receptor Expression in Peripheral Blood Mononuclear Cells of Patients with Mild Cognitive Impairment

Adenosine suppresses immune responses through the adenosine A(2A) receptors (A(2A)R). We evaluated the expression of A(2A)R in blood mononuclear cells (PBMCs) of patients with mild cognitive impairment (MCI), Alzheimer's disease (AD), and controls in order to verify if it may help distinguish different forms of cognitive decline. There was a significant linear increase in both mRNA levels and receptor density from multiple cognitive domain MCI (mcd-MCI) to amnestic MCI (a-MCI), spanning through AD and controls, without any significant difference between the latter two groups of subjects. These data, which need to be confirmed in a larger number of patients, suggest that expression of A(2A)R in PBMCs may be a valuable means of differentiating a-MCI and mcd-MCI.