Elevated plasma histone H4 level predicts increased risk of mortality in patients with sepsis.

Background: Histones play a vital role in the pathogenesis of sepsis. However, studies on histones and the prognosis of sepsis patients are scarce. This study aims to investigate the relationship between histones and other biomarkers of sepsis. Furthermore, we aim to determine the role histones play in the prognosis of sepsis patients to explore the possibility of using them as a potential biomarker of sepsis.

Methods: We performed a prospective observational study on 136 patients. One hundred twenty-six of them had sepsis, and 10 were enrolled as healthy controls. Baseline blood samples were collected for plasma histone H4, cardiac troponin I (TnI), N-terminal pro-b-type natriuretic peptide (NT-proBNP), procalcitonin (PCT), and lactate. The site of infection, the use of vasopressor, and assessment scores of sequential organ failure were documented within 24 hours of admission. The duration of ICU stay and mortality was also recorded.

Results: The mean plasma histone levels of the patients were significantly higher than the healthy controls (P<0.001). Compared with the 89 survivors, the 37 patients who died had a higher rate of sequential organ failure assessment (SOFA) scores (P=0.002), more frequent use of vasopressors (P=0.033), and higher levels of histone H4 (P<0.001). Binary logistic regression analysis showed that high plasma histone H4 levels were independent risk factors for predicting mortality. The area under the receiver operating characteristic curve (0.731) verified that high plasma histone H4 level significantly predicted mortality. Plasma histone H4 levels positively correlated with the SOFA score, and plasma cardiac TnI.

Conclusions: For patients with sepsis in the ICU, an elevated level of plasma histone H4 could be a risk factor associated with an increased mortality rate. Therefore, plasma histone H4 may be a useful biomarker for determining the prognosis of these patients.