{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,11]],"date-time":"2026-10-11T02:13:36Z","timestamp":1791684816629,"version":"4.3.4"},"reference-count":30,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,5,23]],"date-time":"2025-05-23T00:00:00Z","timestamp":1747958400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Transplant."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Long-term survival after lung transplantation is significantly shorter compared with other solid organ transplantations. Chronic lung allograft dysfunction (CLAD), including bronchiolitis obliterans syndrome (BOS), remains the major barrier to survival. CLAD is diagnosed according to ISHLT's guidelines: a 20% drop in FEV<jats:sub>1<\/jats:sub> using spirometry for CLAD grade 1. Given the difficulties of confounders using spirometry, other methods for precise diagnostics are being explored. Exhaled breath particles (EBP) measured as particle flow rate (PFR) from the airways have been explored as a potential method to diagnose lung injury in preclinical and clinical settings of acute respiratory distress syndrome (ARDS) and primary graft dysfunction (PGD). In fact, PFR has been shown to indicate early signs of lung injury in both ARDS and PGD settings. In the present study, we explored whether PFR could be used as a marker for BOS.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Lung transplant patients with different BOS grades were included. All patients were in stable condition without ongoing infections and &amp;gt;2 years posttransplantation. PFR (in particles per liter) was measured using a Particles in Exhaled Air (PExA) 2.0 device (PExA, Gothenburg, Sweden), containing an optical particle counter, at the start of the study and then 1 year out, in total two time points (0 and 1 year). Particles in the diameter range of 0.41\u20134.55\u2005\u00b5m were measured.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>At both the start of the study and 1 year out, patients with BOS grade 0 had significantly higher PFR than patients with BOS grades 2\u20133. During the study period, patients who progressed in their BOS grade all expressed lower PFR as they progressed in BOS grade, while patients who remained stable in BOS grade did not. The particle distribution between the different BOS grades had a similar pattern; however, it significantly decreased PFR with severity in the BOS grade.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>EBP expressed as PFR could be used to distinguish severity in BOS grade and could be used to follow the progression of BOS over time. PFR could be used as a new diagnostic tool for BOS and to follow the development of lung function over time.<\/jats:p><\/jats:sec>","DOI":"10.3389\/frtra.2025.1516728","type":"journal-article","created":{"date-parts":[[2025,5,23]],"date-time":"2025-05-23T05:30:34Z","timestamp":1747978234000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Exhaled breath particles as a diagnostic tool for bronchiolitis obliterans syndrome in lung transplant recipients: a longitudinal study"],"prefix":"10.3389","volume":"4","author":[{"given":"Runchuan","family":"Gu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Embla","family":"Bod\u00e9n","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandra","family":"Lindstedt","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Franziska","family":"Olm","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,5,23]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"268","DOI":"10.1097\/MOT.0000000000000753","article-title":"Survival in adult lung transplantation: where are we in 2020?","volume":"25","author":"Bos","year":"2020","journal-title":"Curr Opin Organ Transplant"},{"key":"B2","doi-asserted-by":"publisher","first-page":"1016","DOI":"10.1016\/j.healun.2020.07.009","article-title":"The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: 37th adult lung transplantation report\u20142020; focus on deceased donor characteristics","volume":"39","author":"Chambers","year":"2020","journal-title":"J Heart Lung Transplant"},{"key":"B3","doi-asserted-by":"publisher","first-page":"853","DOI":"10.1016\/j.jtcvs.2020.09.097","article-title":"Factors associated with short- versus long-term survival after lung transplant","volume":"163","author":"Jawitz","year":"2022","journal-title":"J Thorac Cardiovasc Surg"},{"key":"B4","doi-asserted-by":"publisher","first-page":"394","DOI":"10.1097\/MAT.0000000000001469","article-title":"Primary graft dysfunction in heart transplant recipients-risk factors and longitudinal outcomes","volume":"68","author":"Smith","year":"2022","journal-title":"Asaio j"},{"key":"B5","doi-asserted-by":"publisher","first-page":"897581","DOI":"10.3389\/fmed.2022.897581","article-title":"Impact of lung function decline on mortality in lung transplant recipients: long-term results from the L-CsA-i study for the prevention of bronchiolitis obliterans syndrome","volume":"9","author":"Kneidinger","year":"2022","journal-title":"Front Med (Lausanne)"},{"key":"B6","doi-asserted-by":"publisher","first-page":"1126697","DOI":"10.3389\/fmed.2023.1126697","article-title":"Systems prediction of chronic lung allograft dysfunction: results and perspectives from the cohort of lung transplantation and systems prediction of chronic lung allograft dysfunction cohorts","volume":"10","author":"Pison","year":"2023","journal-title":"Front Med (Lausanne)"},{"key":"B7","doi-asserted-by":"publisher","first-page":"S305","DOI":"10.1016\/j.healun.2021.01.864","article-title":"Factors associated with long-term CLAD-free survival in lung transplantation","volume":"40","author":"Rajagopala","year":"2021","journal-title":"J Heart Lung Transplant"},{"key":"B8","doi-asserted-by":"crossref","DOI":"10.21037\/jtd.2019.03.83","article-title":"Detection, classification, and management of rejection after lung transplantation","author":"Parulekar","year":""},{"key":"B9","doi-asserted-by":"publisher","first-page":"1479","DOI":"10.1183\/09031936.00107514","article-title":"An international ISHLT\/ATS\/ERS clinical practice guideline: diagnosis and management of bronchiolitis obliterans syndrome","volume":"44","author":"Meyer","year":"2014","journal-title":"Eur Respir J"},{"key":"B10","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1007\/978-1-4614-7636-8_4","article-title":"The role of thoracic imaging in the diagnosis of BOS and related disorders","volume-title":"Bronchiolitis Obliterans Syndrome in Lung Transplantation","author":"Kanne","year":"2013"},{"key":"B11","doi-asserted-by":"crossref","DOI":"10.1513\/AnnalsATS.201410-471CME","article-title":"An international ISHLT\/ATS\/ERS clinical practice guideline: summary for clinicians. 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