On the other hand, a few mouse models including 5xFAD, TgCRND8, TREM2 KO as well as APOE4 and TREM2 R47H with 5xFAD background manifested molecular signatures of neuroinflammation including neuroinflammatory responses, antigen processing and presentation as well as adaptive immune responses seen in human AD brains (Fig. 3B). Here, TREM2 is linked to Alzheimer disease.