Human leukocyte antigen-G is upregulated in heart failure patients: a potential novel biomarker.

Immune activation and inflammation play critical roles in the development of heart failure (HF). Human leukocyte antigen-G (HLA-G) is a nonclassical, major histocompatibility complex class I (MHC-I) protein, upregulated in the context of transplantation, malignancy, and inflammation, and has been correlated with various clinical outcomes. We sought to evaluate the utility of plasma HLA-G in identifying patients with HF. We conducted a single-center, cross-sectional pilot study involving 82 patients diagnosed with HF and 10 healthy controls. Concentrations of circulating HLA-G and inflammatory markers were detected with specific enzyme-linked immunosorbent assay kits and quantified according to purified protein standards. The mean age of the patients was 49.1 ± 12.0 years and 62.2% were male. The median and interquartile range of HLA-G levels (U/ml) were significantly higher (p < 0.001) in HF patients (63, 36-98) compared with controls (28, 22-40). Moreover, HLA-G levels that were similarly (p = 0.766) upregulated across all New York Heart Association functional classes. There was no significant correlation between serum HLA-G and other biomarkers. In conclusion, HLA-G is upregulated in patients diagnosed with HF. Its marked elevation even in New York Heart Association class I patients might indicate that serum HLA-G is a more sensitive marker than other classical HF biomarkers.