We review the literature pertaining to AD risk factors which contribute to T‐cell dysfunction, including Apolipoprotein E (ApoE), Aβ, α‐secretase, β‐secretase, γ‐secretase, Tau, and neuroinflammation, with a focus on understanding the role of T‐cell dysfunction in AD progression and the possibility of T cells being a target for successful AD treatments. The gene discussed is MAPT; the disease is Alzheimer disease.