Heparin Binding Protein in Sepsis—A Comprehensive Overview of Pathophysiology, Clinical Usage and Utility as Biomarker

The heparin-binding protein (HBP) is an enzymatically inactive protein of the serine protease family that plays an important role in host response to stress, especially infection and sepsis. It is produced by activated neutrophils due to a variety of stimuli and is part of the immune response that leads to macrophage, lymphocyte, and neutrophil activation and monocyte adhesion. Its most common repository is the azurophilic granules of the neutrophils. HBP has been studied as a biomarker for several infections, including central nervous system infection, respiratory tract infection, and urinary tract infection, and in several settings, including the Emergency Department and Intensive Care Unit, with promising results. As a biomarker for infection and sepsis, HBP has been compared to other commonly used biomarkers such as Neutrophil to Lymphocyte Ratio, White Blood Count, C-reactive protein, and Procalcitonin, with at least comparable performance. Its sharp increase is promising for the early detection of sepsis. The ability to differentiate inflammatory conditions from infections and bacterial from non-bacterial causes of infection has also been demonstrated. The sepsis-related organ damage, as it is represented by the Sequential Organ Failure Assessment score, can also be reflected by the proportional increase in HBP. Consequently, HBP could be a helpful and promising biomarker for sepsis and infection.