TY - JOUR T1 - Inflammatory biomarkers in pulmonary arterial hypertension: ready for clinical implementation? JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.00018-2023 VL - 61 IS - 3 SP - 2300018 AU - Thomas Koudstaal AU - Karin A. Boomars Y1 - 2023/03/01 UR - http://erj.ersjournals.com/content/61/3/2300018.abstract N2 - Boucly and colleagues provide further evidence for the involvement of the immune system in PAH and potential clinical applicability for three inflammatory biomarkers: β-NGF, CXCL9 and TRAIL https://bit.ly/3CEgpDzDespite novel therapies, pulmonary arterial hypertension (PAH) remains a disease with poor survival and a high burden of symptoms and impact on daily life. One of the complicating factors is that patients commonly present themselves with advanced stages of PAH. As shown by Brown et al. [1], 21.1% of the PAH patients in the REVEAL registry reported symptoms for longer than 2 years before recognition and diagnosis of their disease. Therefore, there is an increasing need for earlier detection of PAH. Furthermore, there is a growing call for biomarkers to determine disease severity and act as predictors of prognosis. An increasing body of evidence supports dysregulated immunity in the pathobiology of PAH [2–5]. Histological studies have shown increased perivascular presence of various immune cells, such as T-cells, B-cells and dendritic cells, in the lungs of patients with idiopathic PAH [5]. Moreover, several studies have provided evidence for the pathophysiological involvement of immune cells in both the innate and the adaptive immune system [2, 5]. ER -