A clinical trial comprised of 350 subjects with probable mild to moderate Alzheimer's Disease (AD) will be conducted primarily to determine whether plasmapheresis with infusion of human albumin combined with Intravenous immunoglobulin (IVIG) is able to modify patient's cognitive, functional, behavioral and global domains. There will be 3 treatment groups and one control group. The subjects will be randomized in a 1:1:1:1 proportion.