PT  - JOURNAL ARTICLE
AU  - Annika Hummersgaard Hansen
AU  - Joachim Høg Mortensen
AU  - Sarah Rank Rønnow
AU  - Morten Karsdal
AU  - Anne-Christine Bay-Jensen
AU  - Diana Julie Leeming
AU  - Jannie Marie Bülow Sand
TI  - Neutrophil activity assessed using a novel serological marker of human neutrophil elastase degraded calprotectin is elevated in patients with COPD or IPF
AID  - 10.1183/13993003.congress-2021.PA3697
DP  - 2021 Sep 05
TA  - European Respiratory Journal
PG  - PA3697
VI  - 58
IP  - suppl 65
4099  - http://erj.ersjournals.com/content/58/suppl_65/PA3697.short
4100  - http://erj.ersjournals.com/content/58/suppl_65/PA3697.full
SO  - Eur Respir J2021 Sep 05; 58
AB  - Background: Neutrophils are part of the first cellular response to acute inflammation prompting neutrophil extracellular traps (NETs) triggered by microorganisms and proinflammatory stimuli. Among others, NETs release calprotectin (CP) and human neutrophil elastase (HNE). The aim of this study was to develop a neoepitope-specific assay for HNE degraded CP to serologically assess neutrophil activity in patients with chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF).Methods: A neoepitope-specific monoclonal antibody was raised towards an HNE cleavage site in the calprotectin domain S100A9, which was used to develop a competitive ELISA (CPa9-HNE). Following validation, CPa9-HNE serum levels were evaluated in IPF (n=16), COPD (n=67), and healthy controls (n=39).Results: The CPa9-HNE assay was technically robust with high sensitivity, accuracy, and precision for quantification in serum. Serum CPa9-HNE levels were significantly elevated in patients with COPD (median 247.4 [IQR 179.2-334.7] ng/mL, p<0.0001) or IPF (median 161.0 [IQR 82.86-238.5] ng/mL) compared to healthy controls (median 18.94 [IQR 18.32-32.29] ng/mL). ROC analysis showed almost complete separation of COPD (AUC 0.9996, p<0.0001) and IPF (AUC 0.9679, p<0.0001) from healthy controls.Conclusions: CPa9-HNE was shown to be a technically robust assay, which may be used as a serological marker of neutrophil activity. IPF and COPD patients had increased CPa9-HNE levels compared to healthy controls, indicating that a measure of neutrophil activity is a potential marker for identifying chronic lung disease with a neutrophilic component.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA3697.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).