Reactive microglia indicated by increased CD68 surrounding amyloid plaques (6E10) were observed and increased in the cortex (2.74 ± 0.50 vs. 1.03 ± 0.29, p = 0.0003) of arcAβ mice at 17 months of age compared to NTL mice (n = 3 per group) and were comparable in the hippocampus (1.57 ± 0.40 vs. 0.82 ± 0.35, p = 0.0734) and thalamus (1.61 ± 0.19 vs. 1.10 ± 0.37, p = 0.2874) (Figure 3). The gene discussed is CD68; the disease is amyloidosis.