The invention provides antibody against p40, IL-12 or IL-23 for the prevention or treatment of Alzheimers disease. It further provides ligands to the pair of interleukin 12 or 23 and its specific receptor, specifically an antibody, an antibody fragment, an antibody-like-molecule, for the prevention or treatment of Alzheimers disease. Similarly, siRNA, antisense or transcription factor modulators of gene expression of p19, p35, p40, IL-12R-β1, IL-12R-β2, and/or IL-23R for the prevention or treatment of Alzheimers disease are provided.