Density of both resting and activated microglia was previously reported to significantly increase in 12- and 17-month-old 3xTg-AD mouse hippocampi but not at 9-month-old, only based on polyclonal affinity-purified rat antiserum raised against CD11b (MAC-1)-IR density with no further validation by gene signature [64]. The gene discussed is ITGAM; the disease is Alzheimer disease.