The cell surface markers CD44 and leukocyte common antigen (CD45), and potassium voltage-gated channel subfamily A member 3 (KCNA3, also known as Kv1.3) are expressed at a higher level in the activated microglial cells with a pro-inflammatory phenotype than in the anti-inflammatory microglial cells in AD mouse models. Here, CD44 is linked to Alzheimer disease.