Regulatory T Cell Dysfunction in Idiopathic, Heritable and Connective Tissue-Associated Pulmonary Arterial Hypertension.

Abstract

Pulmonary arterial hypertension (PAH) encompasses a group of conditions with distinct causes. Immunologic disorders are common features of all forms of PAH and contributes to both disease susceptibility and progression. Regulatory T lymphocytes (Treg) are dysfunctional in patients with idiopathic PAH (iPAH) in a leptin-dependent manner. However, it is not known whether these abnormalities are specific to iPAH. Hence, we hypothesized that (1) Treg dysfunction is also present in heritable (hPAH) and connective tissue disease-associated PAH (CTD-PAH); (2) defective leptin-dependent signaling is present in hPAH and CTD-PAH and could contribute to Treg dysfunction; (3) modulating the leptin axis in vivo could protect against Treg dysfunction; and (4) restoration of Treg activity could limit or reverse experimental chronic hypoxia-induced pulmonary hypertension in vivo.