Now THIS is interesting. In a Phase II trial, a plasmapheresis protocol (removing blood plasma from the body, separating it into plasma and cells, and transfusing the cells + 20% albumin back into the bloodstream) slowed progression of decline by 61% compared to controls in patients with moderate Alzheimer's disease.
Scientists theorize that extracting plasma may flush amyloid-beta peptide from the brain into the plasma, thus limiting the disease's impact on the patient's cognitive functions. Additionally, increasing albumin may represent a multi-modal approach to the management of the disease due to it's binding capacity, antioxidant, immune modulatory and anti-inflammatory properties. You can read the PR here.
Here's a decent primer