Elevated levels of IL-17A (> 2 ng/L) were found in five of 32 patients with IPAH (16%), with a mean level of 7.44 ± 5.56 ng/L. In comparison, two healthy subjects also showed detectable IL-17A levels of 6.4 and 9.4 ng/L, respectively. Characteristics of patients related to elevated IL-17A levels are given in Table 1. No significant correlation with clinical disease severity marker, such as 6MWDs or NT-proBNP, time to clinical worsening, or 2-year overall survival, was detected. Merely, the association with tricuspid annular plane systolic excursions raised the question about a protective role for IL-17A in cardiovascular diseases.