The Human leukocyte antigen G (HLA-G) is a non-classical, major histocompatibility complex class I (MHC-I) protein that modulates the immune response, inhibiting it in most cases. Physiologically expressed in the cells of some tissues, it increases in inflammatory reactions. Inflammation appears to play an important role in the development of chronic heart failure. This study aims to evaluate the levels of soluble HLA-G in patients with heart failure and to investigate the relationships between HLA-G and other clinical-functional parameters of the disease. Investigators hypothesize that the plasma levels of HLA-G could correlate with the clinical status of heart failure and could provide indications on patient's prognosis.

Inclusion Criteria:

• Patients with recent diagnosis of chronic heart failure as defined by the guidelines of the European Society of Cardiology (ESC) and with cardiac ejection fraction <40.
• Clinical stability in the previous month prior to recruitment.
• Absence of coexisting autoimmune diseases.

Exclusion Criteria:

• Subjects with over one year chronic heart failure diagnosis and in clinical stability for less than 1 month.
• Presence of autoimmune diseases.

40 subjects with chronic stable heart failure with ejection fraction <40, diagnosed according to the European Society of Cardiology Guidelines