Determination of vWF, Flt-1 and KDR mRNA by quantitative real-time RT-PCR. MSCs were differentiated to endothelial cells by VEGF and challenged with HIV-1 strains and gp120 in the presence or absence of anti-gp120 pAb, anti p24 pAb (panel A) and p5p (panel B). Total RNA was extracted and purified at day 7 and vWF, Flt-1 and KDR mRNAs were analysed. The results were expressed by the ratio between samples and the control represented by VEGF-differentiated cell cultures after 18S ribosomial normalization. The VEGF treated control cell culture mRNA was set at 100. The data represent the mean (+SD) of three independent experiments performed in duplicate. Statistical significance was determined using Student's t test with *p < 0.05.