PIK3CG and dementia: Four protective proteins (PLEK, DAPP1, CSK and CASP3) that decreased postinfection in the BLSA were significantly decreased in dementia cases in the ARIC study, with several other protective proteins (EIF4A1, DSG1, PIK3CG, PRKCB and LYN) showing similar trends (Extended Data Fig. 4 and Supplementary Table 22).