Since, in a previous study, we have shown an APOE allele-dependent association between plasma IgA levels and AD pathology [29], and regarding the proposed pivotal role for APOE in brain IAPP accumulation, aggregation, and vasculopathy, we further found it interesting to investigate if IAPP-autoantibody levels are affected by APOE4 status. The gene discussed is IAPP; the disease is Alzheimer disease.