Volume 149, Issue 6, Pages 1482-1493 (June 2016) Regulatory T Cell Dysfunction in Idiopathic, Heritable and Connective Tissue-Associated Pulmonary Arterial Hypertension  Alice Huertas, MD, PhD, Carole Phan, MS, Jennifer Bordenave, MS, Ly Tu, PhD, Raphaël Thuillet, BS, Morane Le Hiress, PhD, Jérôme Avouac, MD, PhD, Yuichi Tamura, MD, PhD, Yannick Allanore, MD, PhD, Roland Jovan, MD, Olivier Sitbon, MD, PhD, Christophe Guignabert, PhD, Marc Humbert, MD, PhD  CHEST  Volume 149, Issue 6, Pages 1482-1493 (June 2016) DOI: 10.1016/j.chest.2016.01.004 Copyright © 2016 American College of Chest Physicians Terms and Conditions

Figure 1 Treg are dysfunctional in patients with idiopathic, heritable, and connective tissue disease-associated pulmonary arterial hypertension. A, Group data of flow cytometry analysis of intracellular staining with anti-pSTAT3 antibody in Treg, called pSTAT3+ cells, expressed as a percentage of the total Treg population, in control subjects (n = 20), patients with iPAH (n = 30), patients with hPAH (n = 18), and patients with SSc-PAH (n = 14). B, Group data of flow cytometry analysis of pSTAT3+ cells, expressed as a percentage of the total Treg population, in patients with SSc-PAH (n = 14) and patients with SSc (n = 7). C, Group data of flow cytometry analysis of intracellular staining with anti-pSTAT3 antibody in Treg expressing the ObR, called pSTAT3+ cells, expressed as a percentage of the total Treg ObR+ population, in control subjects (n = 20), patients with iPAH (n = 30), patients with hPAH (n = 18), and patients with SSc-PAH (n = 14). D, Group data of flow cytometry analysis of pSTAT3+ cells, expressed as a percentage of the total Treg ObR+ population, in patients with SSc-PAH (n = 14) and patients with SSc (n = 7). Values are expressed as mean ± SEM. ∗P < .05; ∗∗P < .01. hPAH = heritable pulmonary arterial hypertension; iPAH = idiopathic pulmonary arterial hypertension; NS = not significant; ObR = leptin receptor; PAH = pulmonary arterial hypertension; pSTAT3 = phosphorylated STAT3; SSc = systemic sclerosis; STAT3 = signal transducer and activator of transcription 3; Treg = regulatory T lymphocytes. CHEST 2016 149, 1482-1493DOI: (10.1016/j.chest.2016.01.004) Copyright © 2016 American College of Chest Physicians Terms and Conditions

Figure 2 Normal Treg count in patients with idiopathic, heritable, and connective tissue disease-associated pulmonary arterial hypertension. A, Group data of circulating Treg cell count, expressed as percentage of the total CD4+ lymphocyte population, in control subjects (n = 20), patients with iPAH (n = 30), patients with hPAH (n = 18), and patients with SSc-PAH (n = 14). B, Group data of circulating Treg cell count, expressed as percentage of the total CD4+ lymphocyte population, in patients with SSc-PAH (n = 14), and patients with SSc (n = 7). Values are expressed as mean ± SEM. See Figure 1 legend for expansion of abbreviations. CHEST 2016 149, 1482-1493DOI: (10.1016/j.chest.2016.01.004) Copyright © 2016 American College of Chest Physicians Terms and Conditions

Figure 3 Circulating leptin is increased in patients with iPAH and SSc-PAH but not in patients with hPAH. A, Group data of leptin level in serum from control subjects (n = 20), patients with iPAH (n = 30), patients with hPAH (n = 18), and patients with SSc-PAH (n = 14). B, Group data of leptin level in serum from patients with SSc-PAH (n = 14) and patients with SSc (n = 7). Values are expressed as mean ± SEM. ∗P < .05. ∗∗P < .01. See Figure 1 legend for expansion of abbreviations. CHEST 2016 149, 1482-1493DOI: (10.1016/j.chest.2016.01.004) Copyright © 2016 American College of Chest Physicians Terms and Conditions

Figure 4 ObR is differentially expressed in patients with PAH and SSc. A, Group data of ObR expression on circulating Treg, called ObR+ cells, expressed as a percentage of the total Treg population, in control subjects (n = 20), patients with iPAH (n = 30), patients with hPAH (n = 18), and patients with SSc-PAH (n = 14). B, Group data of ObR expression on circulating Treg, called ObR+ cells, expressed as a percentage of the total Treg population, in patients with SSc-PAH (n = 14) and patients with SSc (n = 7). C-D, Correlation between ObR+ cells, expressed as percentage of the total Treg population, and leptin in patients with iPAH (n = 30), patients with hPAH (n = 18), patients with SSc-PAH (n = 14), and patients with SSc (n = 7) (C) and in control subjects (n = 20) (D). E-F, Correlation between ObR+ cells, expressed as a percentage of the total Treg population, and BMI in patients with iPAH (n = 30), patients with hPAH (n = 18), patients with SSc-PAH (n = 14), and patients with SSc (n = 7) (E) and in control subjects (n = 20) (F). Values are expressed as mean ± SEM. ∗P < .05. ∗∗∗P < .001. See Figure 1 legend for expansion of abbreviations. CHEST 2016 149, 1482-1493DOI: (10.1016/j.chest.2016.01.004) Copyright © 2016 American College of Chest Physicians Terms and Conditions

Figure 5 Leptin inhibition attenuates the decrease in Treg function in chronic hypoxia-induced pulmonary hypertension in rats. A, Group data of flow cytometry analysis of intracellular staining with anti-pSTAT3 antibody in Treg, called pSTAT3+ cells, expressed as a percentage of the total Treg population, in wild-type and ZDF rats, exposed to either normoxia or 3 weeks of chronic hypoxia (hypoxia). B, Group data of Treg cell count, expressed as a percentage of the total CD4+ lymphocyte population, in wild-type and ZDF rats, exposed to either normoxia or hypoxia. Values are expressed as mean ± SEM. ∗P < .05. ZDF = Zucker diabetic fatty rats (ZDF/Lepr fa/fa). See Figure 1 legend for expansion of other abbreviations. CHEST 2016 149, 1482-1493DOI: (10.1016/j.chest.2016.01.004) Copyright © 2016 American College of Chest Physicians Terms and Conditions