Association between elevation of plasma biomarkers and monocyte dysfunction and their combination in predicting sepsis: An observational single-centre cohort study

This study aimed to investigate the possible relationship between the two biomarkers presepsin and procalcitonin (PCT) and monocyte immune function, and to explore their combination in mortality prediction in the early stage of sepsis. A total of 198 patients with bacterial infection and diagnosed with sepsis and 40 healthy control subjects were included. Blood samples were collected on admission within 24 h. Plasma concentrations of presepsin and PCT were measured. Expression of monocyte surface CD14, programmed cell death receptor ligand-1 (PD-L1) and human leucocyte Ag (HLA)-DR were determined using flow cytometry. Levels of plasma presepsin and PCT were significantly higher under septic conditions, and increased with the progression of sepsis. Monocyte CD14 and HLA-DR expression were decreased, while PD-L1 was overexpressed in sepsis compared to control. Presepsin and PCT concentrations were positively correlated with Sequential Organ Failure Assessment score, Acute Physiology and Chronic Health Evaluation System II score and PD-L1, while they were negatively correlated with CD14 and HLA-DR. Presepsin plus monocyte HLA-DR mean fluorescence intensity had the highest prognostic value over other parameters alone or in combination. Presepsin and PCT had a weak correlation with monocyte dysfunction during early sepsis. The combination of presepsin and monocyte HLA-DR could help improve prognostic value.