Immune-specific Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed that APOE ε4 proteins were enriched in numerous infection-related pathways, including hepatitis, herpes, measles, Epstein–Barr virus (EBV), and influenza A. There was also significant enrichment for T cell, B cell and inflammatory signaling cascades, including Toll‐like receptor (TLR), tumor necrosis factor (TNF), interleukin 17 (IL-17), JAK/STAT and nuclear factor-κB (NF-κB; Fig. 1h and Supplementary Table 3). Here, IL17A is linked to infection.