IGFBP6 and AIDS: After normalization by the β-actin, the expression level of IGFBP6 was down-regulated by 65.9% in HIV/AIDS patients relative to normal controls (Fig. 4a, P = 0.04, one sided Mann-Whitney U test) while SATB2 was down-regulated by 57.1% (Fig. 4b, P = 0.027).