Within the set of proteins found in at least 3 iTRAQ experiments, α-2 macroglobulin and C4b-binding protein were the two proteins showing the most prominent abundance deficit in HDL from AAA patients compared with controls, whereas PRDX6, HLA-I, retinol-binding protein 4, and PON1 were the proteins showing the largest abundance increases (Fig. 2). This evidence concerns the gene RBP4 and triple-A syndrome.