Bielschowsky, iC3b, and C9 plaque counts were 2.5- to 3-fold higher in AD specimens than in the other groups (p = 0.0002, 0.0116, and 0.0130 for Bielschowsky, iC3b, and C9 staining, respectively) (Fig. 2), but were similar between AN and MCI specimens. This evidence concerns the gene C9 and Alzheimer disease.