Pulmonary Arterial Hypertension or PAH is a progressive condition for which there is no cure. Even with substantial pharmacologic advances in the modern treatment era, survival still remains unacceptably poor, as reported in large PAH registries. Preclinical studies suggest that the administration of allogeneic CDCs have the potential to reduce adverse arteriolar remodeling in PAH which was the basis for the approved investigational new drug (IND). The use of CDCs as an adjunctive therapy in patients comprising 4 sub-groups of patients with PAH in which inflammation and immune dysfunction are key pathophysiologic drivers of PAH.