PIK3CG and Alzheimer disease: Our hypothesis that infections may increase levels of pathogenic immune proteins was supported and complemented by the finding that infection history, primarily influenza, was also associated with decreases in protective proteins, such as PIK3CG, PACSIN2 and PRKCB: proteins that have been previously implicated in neurodegeneration44–46, and were associated with reduced brain volume loss, preserved cognitive capacities and lower levels of AD pathology in our study.