Extravascular T cell numbers have also been reported to correlate with abundance of tau in AD brain but not in control brains.76 Brain infiltrating CD8+ T cells express higher levels of the cytotoxic proteins granzyme A78 and perforin-179 in AD brains relative to healthy control brains, suggestive of a phenotype poised for degranulation. The gene discussed is PRF1; the disease is Alzheimer disease.