In the fourth cohort, the authors revealed the cytotoxic function of clonal TEMRA cells from the CSF of patients with AD, including high expression levels of cytotoxic effectors (granule protein 7, NKG7 and granzymes A, GZMA) and the pro-aging factor (beta-2-microglobulin, B2M). The gene discussed is B2M; the disease is Alzheimer disease.