A large number of Alzheimer's disease susceptibility gene candidates, including clusterin and complement receptor 1, as well as diverse interleukins and other cytokines, C reactive protein, HLA-antigens, Fc epsilon and Toll receptors, and the viral-activated kinase PKR, are intimately concerned with pathogen defence and or the immune system, supporting a genetic contribution to the immune pathogenesis of Alzheimer's disease (see http://www.polygenicpathways.co.uk/alzpolys.html). This evidence concerns the gene CRP and early-onset autosomal dominant Alzheimer disease.