with pulmonary arterial hypertension (PAH) and can predict the survival of patients with
idiopathic PAH (IPAH). Previous animal experiments and clinical human studies indicate
that IL-6 is important in PAH; however, the molecular mechanisms of IL-6–mediated
pathogenesis of PAH have been elusive. Here we identified IL-21 as a downstream target of
IL-6 signaling in PAH. First, we found that IL-6 blockade by the monoclonal anti-IL-6 receptor …