We also observed reduced expression of the AD-associated gene Chi3l1, which we expected to increase microglial activation and reduce plaque burden due to our previous report39 However, as these effects were not seen in this study, we suspect that greater suppression of Chi3l1 over a longer time frame as seen for Chi3l1 knockout mice is required to produce this reduction in plaque load. This evidence concerns the gene CHI3L1 and Alzheimer disease.