The interpretation that treatment of patients with the anti-Aβ monoclonal antibody bapineuzumab had an effect on lowering levels of phospho-tau is consistent with our findings in postmortem studies of the brains of patients actively immunized against Aβ (AN1792). In this study, we found that, as Aβ plaques are cleared from the brain, there is a reduction in the overall level of histologically detectable phospho-tau. Interestingly, the effect seemed to be restricted to phospho-tau in neuronal processes (both in plaque-associated dystrophic neurites and in neuropil threads), but with no change in phospho-tau located in the cell bodies (i.e., in effect, the tangles). As mentioned in this story, we also interpreted our observation as support for the amyloid hypothesis in that, as changing Aβ can alter phospho-tau, then this implies that tau phosphorylation is downstream of Aβ alterations.

References:
Boche D, Donald J, Love S, Harris S, Neal JW, Holmes C, Nicoll JA. Reduction of aggregated Tau in neuronal processes but not in the cell bodies after Aβ42 immunisation in Alzheimer's disease. Acta Neuropathol. 2010;120:13-20. Abstract

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