Bielschowsky, iC3b, and C9 plaque staining. Means for Bielschowsky, iC3b, and C9 plaque counts in eight 10× fields of high plaque density were significantly increased in AD specimens vs. other groups. Data are expressed as means ± SEM. Abbreviations: AD, Alzheimer's disease; AN, aged normal; Biel, Bielschowsky staining; MCI, mild cognitive impairment. (*p < 0.05 vs. AN and MCI).