S100A9 and Alzheimer disease: In AD we have shown the similarity of the plaques containing only S100A9 and mixed Aβ-S100A9 senile plaques with regards to their (a) amyloidogenic properties, such as staining with amyloid-specific h-FTAA dye, A11 and OC antibodies, and (b) morphological features shown by AFM (Fig. 5).