RIG-1 is elevated in the plasma of mild cognitive impairment (MCI) patients. Representative immunoblots (A) of plasma (B) and serum (C) from age-matched controls (NCI), MCI and Alzheimer Disease (AD) patients analyzed for RIG-1 expression. 5 μg of protein were loaded for the plasma and serum samples after removal of IgG. Data presented as mean ± SEM. *P < 0.05. N = NCI: 6, MCI: 7 and AD: 10 patients.