In reply
The question raised by Tremolizzo and colleagues relates to their recent observation that treatments with acetylcholinesterase inhibitors could impact the circulating levels of anti–amyloid β (Aβ) antibodies.1 As a matter of fact, our observation of significant differences in anti-Aβ antibody levels between patients with typical Alzheimer disease (AD) and patients with posterior cortical atrophy with evidence of AD (PCA-AD)2 could have been influenced by external factors including treatments. However, this possibility may be ruled out for the following 2 main reasons.