We are measuring the biochemical markers of Aβ(1-40) and Aβ(1-42), P-tau and T-tau, matrix metalloproteinases (MMP-2, MMP-9), pro-inflammatory cytokines (IL-1beta, TNF-alpha), and anti-inflammatory cytokines (IL-4 and IL-10) at the start and one year after treatment in the multi-centered, randomized, controlled, trial of disease-modifying drugs rifampicin and/or and doxycycline to slow the progress of Alzheimer's disease by affecting the production of these biomarkers.