{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:21:45Z","timestamp":1785424905336,"version":"3.56.0"},"reference-count":41,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T00:00:00Z","timestamp":1777334400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100023969","name":"Hellenic Thoracic Society","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100023969","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/05f32qs32","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background and Aims: Plasma fibrinogen and fractional exhaled nitric oxide (FeNO) reflect neutrophilic and eosinophilic airway inflammation, respectively, and are associated with disease activity and severity in different directions in bronchiectasis. This study aimed to concurrently investigate fibrinogen and FeNO and further evaluate the clinical importance of fibrinogen-to-FeNO ratio (FFR) as a composite biomarker in bronchiectasis. Methods: This was a two-centre, observational, cross-sectional study involving stable bronchiectasis patients. Fibrinogen, FeNO, and the ratio of their normalised values (FFR) were investigated in relation to clinical indicators of disease activity and severity, including respiratory symptoms, inflammatory markers, pulmonary function, radiological extent, airway infection, severity scores, and patient-reported outcomes. Results: FFR was correlated with both circulating neutrophils (r = 0.36, p = 0.04) and eosinophils (r = \u22120.39, p = 0.03) and, more strongly compared to fibrinogen and FeNO, with the percentage of predicted forced expiratory volume in the 1st second (r = \u22120.61, p &lt; 0.001). Interestingly, only FFR was found to be higher in patients with Pseudomonas aeruginosa isolation in respiratory secretions (p &lt; 0.01). In receiver operating characteristic curves, FFR showed good discriminatory ability to differentiate patients with any level (AUC: 0.80, 95% CI: 0.64\u20130.96) or a severe level (AUC: 0.83, 95% CI: 0.64\u20131.00) of pulmonary functional impairment and patients with severe disease (AUC: 0.78, 95% CI: 0.62\u20130.94). Conclusions: FFR emerges as a candidate biomarker capturing the balance between neutrophilic and eosinophilic inflammation and the net disease activity and severity in bronchiectasis.<\/jats:p>","DOI":"10.3390\/jcm15093383","type":"journal-article","created":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T07:43:51Z","timestamp":1777448631000},"page":"3383","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Plasma Fibrinogen-to-Fractional Exhaled Nitric Oxide Ratio (FFR) as an Emerging Biomarker in Bronchiectasis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1941-0213","authenticated-orcid":false,"given":"Andreas M.","family":"Matthaiou","sequence":"first","affiliation":[{"name":"Laboratory of Molecular and Cellular Pneumonology, School of Medicine, University of Crete, 70013 Heraklion, Greece"},{"name":"Department of Respiratory Medicine, University Hospital of Heraklion, 71500 Heraklion, Greece"},{"name":"5th Department of Respiratory Medicine, Sotiria Thoracic Diseases General Hospital of Athens, 11527 Athens, Greece"},{"name":"Respiratory Physiology Laboratory, Medical School, University of Cyprus, Nicosia 2029, Cyprus"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5199-1519","authenticated-orcid":false,"given":"Nikoleta","family":"Bizymi","sequence":"additional","affiliation":[{"name":"Laboratory of Molecular and Cellular Pneumonology, School of Medicine, University of Crete, 70013 Heraklion, Greece"},{"name":"Department of Respiratory Medicine, University Hospital of Heraklion, 71500 Heraklion, Greece"},{"name":"5th Department of Respiratory Medicine, Sotiria Thoracic Diseases General Hospital of Athens, 11527 Athens, Greece"},{"name":"Department of Nursing, School of Health Sciences, National and Kapodistrian University of Athens, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9978-4823","authenticated-orcid":false,"given":"Ioannis","family":"Tomos","sequence":"additional","affiliation":[{"name":"5th Department of Respiratory Medicine, Sotiria Thoracic Diseases General Hospital of Athens, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Konstantina","family":"Symvoulaki","sequence":"additional","affiliation":[{"name":"School of Medicine, European University Cyprus, Nicosia 2404, Cyprus"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christos","family":"Skiadas","sequence":"additional","affiliation":[{"name":"Department of Medical Imaging, University Hospital of Heraklion, 71500 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-3836-9390","authenticated-orcid":false,"given":"Georgios","family":"Pitsidianakis","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, University Hospital of Heraklion, 71500 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adamantia","family":"Liapikou","sequence":"additional","affiliation":[{"name":"5th Department of Respiratory Medicine, Sotiria Thoracic Diseases General Hospital of Athens, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nikolaos","family":"Tzanakis","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, University Hospital of Heraklion, 71500 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katerina M.","family":"Antoniou","sequence":"additional","affiliation":[{"name":"Laboratory of Molecular and Cellular Pneumonology, School of Medicine, University of Crete, 70013 Heraklion, Greece"},{"name":"Department of Respiratory Medicine, University Hospital of Heraklion, 71500 Heraklion, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"880","DOI":"10.1016\/S0140-6736(18)31767-7","article-title":"Advances in Bronchiectasis: Endotyping, Genetics, Microbiome, and Disease Heterogeneity","volume":"392","author":"Flume","year":"2018","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1001\/jama.2025.2680","article-title":"Non-Cystic Fibrosis Bronchiectasis in Adults: A Review","volume":"334","author":"Barker","year":"2025","journal-title":"JAMA"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Campisi, R., Nolasco, S., Mancuso, M., Spinella, M., Vignera, F., Crimi, N., Vancheri, C., and Crimi, C. 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