RBP4 and type 2 diabetes mellitus: In patients with type 2 diabetes, elevated tumor necrosis factor α (TNFα), C-reactive protein (CRP), interleukin (IL) -1, -6, -8, plasminogen activator inhibitor-1 (PAI-1), retinol binding protein 4 (RBP4), chemerin, fetuin-A, visfatin/Nampt, resistin and reduced adiponectin and IL-10 serum concentrations have been reported [7]–[11], reviewed in [1], [5].