Use of Fc Mannose-Binding Lectin to Detect and Monitor the Presence of Pathogen-Associated Molecular Patterns During Septic Shock

Septic shock still represent a major cause of admission in intensive care unit, incidence of severe sepsis is increasing, even in western countries, due to aging populations and comorbidities. Definition of septic shock was revised in 2016 by a task force, which emphasizes the need for future iterations. Indeed, there are no simple clinical or biological criteria ton diagnose septic patients with high risk of shock, or to prognose its severity. C-reactive protein (CRP) and procalcitonin (PCT) are the wider biomarkers used to monitor septic patients. But they do not correlate with sepsis severity and moreover do not distinguish unequivocally between infection and noninfected systemic inflammatory response syndrome (SIRS). Each microorganism has number of PAMPs, cell wall components (lipopolysaccharide endotoxin, peptidoglycan, outer membrane vesicles), flagella, mannan... High levels of these pathogen fragments are released in the bloodstream during sepsis. They trigger release of inflammatory cytokines that drive the sepsis cascade. Mannose binding lectin plays a pivotal role in innate immunity, binding with surface sugars of wide range of pathogens and their fragments. Thus MBL promotes opsonophagocytosis and activates the lectin-complement pathway. Fc-MBL, an engineered version of MBL has been developed to capture microorganism and treat sepsis. An ELISA, using Fc-MBL was developed to measure PAMPs in whole blood during sepsis. This assay will use Fc-MBL ELISA to quantify PAMPs during septic shock, to improve diagnostic and monitoring. But also, identifying patients with high levels of PAMPs for dialysis-like sepsis therapies.

PAMP's level will be compared to clinical, biological, microbiological and therapeutic outcomes. Its sensitivity will be evaluated by its kinetic among a septic shock (defined with Sepsis-3 criteria) and by correlation with CRP (C-Reactive Protein) and PCT (Procalcitonin). Its specificity will be evaluated by comparing its levels during septic and non-septic shocks.