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

BACKGROUND: 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. METHODS: We analyzed 62 patients with PAH (30 with iPAH, 18 with hPAH, and 14 with CTD-PAH), 7 patients with CTD without PAH, and 20 healthy control subjects. RESULTS: Our results indicate that Treg are dysfunctional in all PAH forms tested, as well as in patients with CTD without PAH. Importantly, the leptin axis is crucial in Treg dysfunction in patients with iPAH and those with CTD (with or without PAH), whereas in patients with hPAH, Treg are altered in a leptin-independent manner. We found that leptin receptor-deficient rats, which develop less severe hypoxia-induced pulmonary hypertension, are protected against decreased Treg function after hypoxic exposure. CONCLUSIONS: Taken together, our results suggest that Treg dysfunction is common to all forms of PAH and may contribute to the development and the progression of the disease.

Pulmonary Hypertension Complicating Fibrosing Mediastinitis.

Fibrosing mediastinitis is caused by a proliferation of fibrous tissue in the mediastinum with encasement of mediastinal viscera and compression of mediastinal bronchovascular structures. Pulmonary hypertension (PH) is a severe complication of fibrosing mediastinitis caused by extrinsic compression of the pulmonary arteries and/or veins.We have conducted a retrospective observational study reviewing clinical, functional, hemodynamic, radiological characteristics, and outcome of 27 consecutive cases of PH associated with fibrosing mediastinitis diagnosed between 2003 and 2014 at the French Referral Centre for PH.Fourteen men and 13 women with a median age of 60 years (range 18-84) had PH confirmed on right heart catheterization. The causes of fibrosing mediastinitis were sarcoidosis (n = 13), tuberculosis-infection confirmed or suspected (n = 9), mediastinal irradiation (n = 2), and idiopathic (n = 3). Sixteen patients (59%) were in NYHA functional class III and IV. Right heart catheterization confirmed moderate to severe PH with a median mean pulmonary artery pressure of 42 mm Hg (range 27-90) and a median cardiac index of 2.8 L/min/m (range 1.6-4.3). Precapillary PH was found in 22 patients, postcapillary PH in 2, and combined postcapillary and precapillary PH in 3. Severe extrinsic compression of pulmonary arteries (>60% reduction in diameter) was evidenced in 2, 8, and 12 patients at the main, lobar, or segmental levels, respectively. Fourteen patients had at least one severe pulmonary venous compression with associated pleural effusion in 6 of them. PAH therapy was initiated in 7 patients and corticosteroid therapy (0.5-1 mg/kg/day) was initiated in 3 patients with sarcoidosis, with 9 other being already on low-dose corticosteroids. At 1-year follow-up, 3 patients had died and among the 21 patients evaluated, 3 deteriorated, 14 were stable, and only 4 patients with sarcoidosis improved (4 receiving corticosteroids and 1 receiving corticosteroids and PAH therapy). Survival was 88%, 73%, and 56% at 1, 3, and 5 years, respectively.We found no clear clinical improvement with the use of specific PAH therapy. Corticosteroid therapy may be associated with clinical improvement, in some patients with fibrosing mediastinitis due to sarcoidosis. Although never performed for this indication, lung transplantation may be proposed in eligible patients with severe PH and fibrosing mediastinitis.

[Venous thromboembolism during pregnancy]. / Maladie veineuse thromboembolique et grossesse.

Pulmonary embolism is one of the most common cause of maternal death in developed countries. Pregnancy is associated with a hypercoagulable state, increased especially in patients with thrombophilia. The post-partum period is the period carrying the highest risk of venous thromboembolism, especially after caesarean delivery. The diagnosis is essential, applying strategies validated in the non-pregnant population, as none of the diagnostic tests is contra-indicated during pregnancy. These strategies use a combination of empirical evaluation of clinical probability, D-Dimer measurement. In case of positive D-Dimer testing (or high clinical probability), ultrasonography of the legs should be performed first; if there is no proximal deep vein thrombosis, pulmonary CT scan or lung scan should be performed. Low molecular weight heparin is the treatment of choice until 6 weeks after the delivery, for a minimal total duration of 6 months. The prophylaxis must be individually decided according to histories and risk factors of the patient.

Pulmonary arterial hypertension in patients treated with interferon.

Isolated cases of pulmonary arterial hypertension (PAH) in patients treated with interferon (IFN) α or ß have been reported in the literature. The aim of this study was to describe all consecutive cases of PAH patients with a history of IFN exposure identified in the French reference centre for severe pulmonary hypertension between 1998 and 2012. A total of 53 patients with PAH and a history of IFN therapy were identified. 48 patients had been treated with IFNα for chronic hepatitis C. Most of them had portal hypertension (85%) and 56% had HIV co-infection. Five additional patients had been treated with IFNß for multiple sclerosis. The diagnosis of PAH was made within 3 years after IFN therapy in 66% of patients. Repeated haemodynamic assessment was available in 13 out of 16 patients exposed to IFN after the diagnosis of PAH. Increased pulmonary vascular resistance >20% was observed in 11 out of 13 cases (median 43% increase; IQR 32-67%). In five of these patients, IFN withdrawal resulted in spontaneous haemodynamic improvement. This retrospective analysis suggests that IFN therapy may trigger PAH. However, most of these patients had other risk factors for PAH. A prospective case-control study is necessary to definitively establish a link between IFN exposure and PAH.