The present invention provides, among other aspects, methods for the treatment of Alzheimer's disease in a subject in need thereof, the method including administration of a therapeutically effective amount of a pooled human immunoglobulin G (IgG) composition to a subject with moderately severe Alzheimer's disease, a subject carrying an ApoE4 allele, or both, where the amount of pooled human IgG is from 300 mg/kg to 800 mg/kg body weight of the subject per two week period, and where the amount is administered in one or more doses during the two week period after initiation of a therapeutic regimen. Also provided, are methods for selecting a treatment regimen for a subject with Alzheimer's disease, including diagnosing the severity of the Alzheimer's disease, determining if the subject carries an APOE4 allele, or both, and assigning a treatment regimen including administration of pooled human immunoglobulin G and/or an anti-beta amyloid monoclonal antibody.