ERAP1 and Alzheimer disease: Second, as the immunoproteasome produces peptides which may be later presented by HLA class I molecules, the TAP1/TAP2 complex transfers these peptides to the endoplasmic reticulum where they may be bound by HLA-class I molecules, and endoplasmic reticulum aminopeptidases ERAP1 and ERAP2 trim these peptides for better binding by HLA class I molecules, it would be interesting to check whether some combinations of LMP and TAP variants together with optimal ERAP variants provide better peptide repertoire for protection against AD development and/or severity.