B-075 Biophysical Changes of Leukocyte Activation (and NETosis) in the Cellular Host Response to Sepsis

Abstract Background During sepsis, neutrophils, upon activation, undergo biophysical and biochemical changes that may terminate in the release of neutrophil extracellular traps (NETs) (1–3). The IntelliSep test is a rapid sepsis diagnostic assesses immune activation by quantifying properties leukocytes from whole blood <10 minutes. results Index (ISI), ranging between 0.1–10.0, stratified into three interpretation bands (Band 1, Band 2, 3) based on probability clinical syndrome (4, 5). We investigated correlation result immunological observed during leukocyte through in-vitro studies using samples non-septic septic patients. Methods In-vitro Studies: Healthy were collected April - August 2022 18 volunteers at donor center. Aliquots each sample incubated for 10 minutes with phorbol myristate acetate (PMA) phosphate-buffered saline one 3 concentrations: 0, 200, 400 nM prior to (3 repeats per concentration). Clinical Subjects signs or symptoms infection enrolled Emergency Departments (EDs) similar but distinct prospective cohort (February 2016—September 2019) (1, 2). was performed aliquot fresh subject, remnant plasma prepared frozen later analysis. Plasma levels elastase-DNA (NE DNA) citrullinated histone H3-DNA (Cit-H3 complexes quantified previously reported custom ELISAs 3,6. retrospectively adjudicated as sick (adjudicated SOFA scores peaking day enrollment compared two subsequent days) “healthy” (SOFA <2, hospital length stay <3 days). Results Significant increases ISI increasing concentration PMA healthy (0 200: P < 10−10; 0 400: 10−10). analysis consisted 39 “sick” 42 subjects. Linear NE DNA Cit-H3 quantities significant across Interpretation Bands 1 3: 0.001). Conclusion Correlation supports hypothesis measured activation. Observed NET suggest formation pathways ISI. Together these experiments support cellular host response could provide window patient’s state dysregulated immunity have potential aid ED physicians timely diagnosis sepsis.