CD8A and Alzheimer disease: Contrarily, a study by Chen et al. demonstrated that microglial recruitment of T-cells in response to tauopathy, but not amyloid deposition, leads to neurodegeneration in AD [72], and a study by Merlini et al. reported CD3 + T-cells, most of which were CD8 + , to correlate with tau, but not amyloid, pathology in the AD brain [10].