Increasing evidence points towards an inflammatory component underlying pulmonary hypertension. However, the conclusive characterisation of multiple inflammatory cell populations in the lung is challenging due to the complexity of marker specificity and tissue inaccessibility. We used an unbiased computational flow cytometry approach to delineate the inflammatory landscape of idiopathic pulmonary arterial hypertension (IPAH) and healthy donor lungs.Donor and IPAH samples were discriminated clearly using principal component analysis to reduce the multidimensional data obtained from single-cell flow cytometry analysis. In IPAH lungs, the predominant CD45 cell type switched from neutrophils to CD3 T-cells, with increases in CD4, CD8 and γδT-cell subsets. Additionally, diversely activated classical myeloid-derived dendritic cells (CD14HLA-DRCD11cCD1a) and nonclassical plasmacytoid dendritic cells (pDCs; CD14CD11cCD123HLA-DR), together with mast cells and basophils, were more abundant in IPAH samples. We describe, for the first time, the presence and regulation of two cell types in IPAH, γδT-cells and pDCs, which link innate and adaptive immunity.With our high-throughput flow cytometry with multidimensional dataset analysis, we have revealed the interactive interplay between multiple inflammatory cells is a crucial part of their integrative network. The identification of γδT-cells and pDCs in this disease potentially provides a missing link between IPAH, autoimmunity and inflammation.

In patients at risk for PH and/or with unexplained dyspnea, CART analysis detects prognostic thresholds at a resting mPAP of 17 mm Hg and 26 mm Hg, and values between 20 mm Hg and 25 mm Hg represent an independent predictor of poor survival. Clinical trial registered with www.clinicaltrials.gov (NCT 01607502).

Chronic thromboembolic pulmonary hypertension (CTEPH) is associated with chronic inflammation but the pathological mechanisms are largely unknown. Our study aimed to simultaneously profile a broad range of cytokines in the supernatant of pulmonary endarterectomy (PEA) surgical material, as well as prospectively in patients with CTEPH to investigate whether circulating cytokines are associated with haemodynamic and physical characteristics of CTEPH patients.Herein, we show that PEA specimens revealed a significant upregulation of interleukin (IL)-6, monocyte chemoattractant protein-1, interferon-c-induced protein-10 (IP)-10, macrophage inflammatory protein (MIP)1a and RANTES compared to lung tissue from healthy controls.In prospectively collected serum, levels of IL-6, IL-8, IP-10, monokine induced by interferon-c (MIG) and MIP1a were significantly elevated in CTEPH patients compared to age-and sex-matched healthy controls. In serum of idiopathic pulmonary arterial hypertension (IPAH) patients, only IP-10 and MIG were significantly increased. In CTEPH but not in IPAH, IP-10 was negatively correlated with cardiac index, 6-min walking distance and carbon monoxide diffusion capacity. In vitro, IP-10 significantly increased migration of freshly isolated adventitial fibroblasts.Our study is the first to show that IP-10 secretion is associated with poor pulmonary haemodynamics and physical capacity in CTEPH and might be involved in the pathological mechanism of PEA tissue formation. @ERSpublications Increased circulating IP-10 associated with poor pulmonary haemodynamics and physical capacity in CTEPH patients

No abstract