PPIB and type 2 diabetes mellitus: To identify the most and the least stable reference gene in PBMCs from T2DM patients, we tested gene-expression stability of 4 potential reference genes (ACTB, YWHAZ, PPIB, and GAPDH) in PBMCs of T2DM patients (n = 39) and compared them to that of NGT subjects (n = 47).