IL6 and pulmonary arterial hypertension: Moreover, primary human lung pericytes isolated based on the expression of 3G5-ganglioside antigen (3G5) show increased proliferative and migratory responses when exposed to conditioned medium from PAH endothelial cells compared with controls, a mechanism that involves fibroblast growth factor 2 (FGF2) and interleukin 6 (IL-6) signaling pathways [27].