Detectable interleukin-9 plasma levels are associated with impaired cardiopulmonary functional capacity and all-cause mortality in patients with chronic heart failure.

Inflammatory activation plays a pivotal role in chronic heart failure (CHF) through the increased expression of pro-inflammatory cytokines [1]. Decreased plasma levels of Interleukin (IL-) 5, IL-7 and Interferon-γ (IFN-γ) and increased levels of IL-9 have been already described in CHF [2], and a negative correlation was also reported between IL-9 and left ventricular ejection fraction (LVEF) [2]. Yet, there are only limited data exploring the association between cytokines and functional capacity in CHF and their prognostic role [3]; therefore, primary end-point of the current study was to evaluate all-cause mortality according to changes in cytokines plasma levels in CHF patients.