Genes enriched in human monocytes and macrophages that affected T cells during human craniotomy infection included those involved in activation (TNFSF12-TNFRSF25, ICOSLG-ICOS, CD86-CTLA4, and CD86-CD28) and adhesion and chemotaxis (LAMC1–integrin-α6β1, CXCL16-CXCR6, CXCL2-DPP4, CCL20-CCR6, and PLAUR–integrin α4β1 complex) (Figure 9D). This evidence concerns the gene DPP4 and infection.