Co-targeting CD33 when conducting passive immunization by using an antibody against post-translationally modified Aβ may have several advantages: (I) combinational therapy results in an add-on effect on passive immunotherapy alone; (II) anti-CD33 antibodies/inhibitors have already been developed for treatment of AML and might be easily repurposed for application in AD; (III) the success rate in clinical trials might be increased by the selection of patients carrying the AD-associated risk allele rs3865444C in the proximal promoter of CD33. The gene discussed is CD33; the disease is Alzheimer disease.