Pulmonary epithelial markers in phenotypes of chronic lung allograft dysfunction

https://doi.org/10.1016/j.healun.2023.03.009Get rights and content

Background

Airway epithelial injury is thought to be a key event in the pathogenesis of chronic lung allograft dysfunction (CLAD). We investigated whether markers of epithelial activity and injury in bronchoalveolar lavage fluid (BAL) correlate with CLAD diagnosis and major CLAD phenotypes: bronchiolitis obliterans syndrome (BOS) vs restrictive allograft syndrome (RAS)-related phenotypes (including RAS, mixed phenotype, and all other patients with RAS-like opacities).

Methods

CLAD status and phenotypes were retrospectively determined in a cohort of all consecutive adult, first, bilateral lung transplants performed 2010-2015, with available BAL samples. All patients with RAS-related phenotypes were included and 1:1 matched with BOS patients based on the time from transplant to CLAD-onset. Subjects who were CLAD-free for a minimum of 3 years post-transplant were 1:1 matched to CLAD patients and included as controls. Proteins that maintain the barrier function of the airway epithelial mucosa (club cell secretory protein, surfactant protein-D and epithelial mucins: MUC1, MUC5AC, MUC5B, MUC16), as well as epithelial cell death markers (M30&M65 representing epithelial cell apoptosis and overall death, respectively), were measured in BAL obtained within 6-months post CLAD onset using a double-sandwich ELISA or a multiplex bead assay. Protein levels were compared using Mann-Whitney-U-test. Association between protein levels and graft survival was assessed using Cox proportional hazards models, adjusted for CMV serology mismatch status and CLAD phenotype.

Results

Fifty-four CLAD (27 BOS, 11 RAS, 7 mixed, 9 others with RAS-like opacities) patients and 23 CLAD-free controls were included. Median BAL levels were significantly higher in patients with CLAD compared to CLAD-free controls for M30 (124.5 vs 88.7 U/L), MUC1 (6.8 vs 3.2 pg/mL), and MUC16 (121.0 vs 30.1 pg/mL). When comparing CLAD phenotypes, M30 was significantly higher in patients with RAS-related phenotypes than BOS (160.9 vs 114.6 U/L). In multivariable models, higher M30 and MUC5B levels were associated with decreased allograft survival after CLAD onset independent of phenotype (p < 0.05 for all).

Conclusions

Airway epithelial mucins and cell death markers are enhanced in the BAL of patients with CLAD and can assist in differentiating between CLAD phenotypes and post-CLAD outcomes. Abnormal airway mucin expression and epithelial cell death may be involved in the pathogenesis of CLAD, and therefore their detection may aid in future selection of targeted therapies.

Section snippets

Study design and patient selection

This was a single-center, retrospective cohort study approved by the Institutional Research Ethics Board. The study population was drawn from all first, adult, bilateral, LT recipients at Toronto General Hospital who underwent a LT operation between January 1, 2010, and December 31, 2015: this cohort is a subset of a previously-published CLAD cohort.17 All patients with RAS, mixed phenotype and undefined or unclassified with RLO, who had a BAL sample obtained within 6 months after CLAD onset,

Patient cohort characteristics

Of the 506 adult, bilateral, first LT recipients who had a transplant operation between January 1, 2010, and December 31, 2015, 39 were excluded due to insufficient PFT data precluding CLAD diagnosis and 19 because the diagnosis of CLAD was incompletely substantiated or unconfirmed. Fifty-four patients who had a BAL sample obtained within 6 months after CLAD onset (27 BOS, 11 RAS, 7 Mixed, 9 other-RLO) and 23 CLAD-free controls who were alive and CLAD-free for a minimum of 3 years

Discussion

In this study, we evaluated the utility of pulmonary epithelial markers of injury or death in BAL fluid for the diagnosis and phenotyping of CLAD. We used BAL fluid obtained within 6 months after CLAD onset to assess differences in levels of various epithelial markers comparing CLAD vs CLAD-free controls and comparing CLAD phenotypes, BOS vs combined RAS, mixed and other-RLO. We tested an array of epithelial markers selected based on existing literature. We demonstrate elevated BAL levels of

Disclosure statement

TM has received CCSP-related research material from APCBio Innovations, Inc. and collaborates with Trove Therapeutics, Inc. on CCSP-related research. These companies were not involved in the design or analysis of the study. The other authors of this manuscript have no conflicts of interest to disclose.

This research was supported in part by a grant from The Canadian Institutes of Health Research (to TM, #149094), a grant from The Physicians' Services Inc. Foundation (to LL and TM), a Cystic

References (44)

  • N Festjens et al.

    Necrosis, a well-orchestrated form of cell demise: signalling cascades, important mediators and concomitant immune response

    Biochim Biophys Acta

    (2006)
  • A Gadducci et al.

    The predictive and prognostic value of serum CA 125 half-life during paclitaxel/platinum-based chemotherapy in patients with advanced ovarian carcinoma

    Gynecol Oncol

    (2004)
  • S Cedres et al.

    Serum tumor markers CEA, CYFRA21-1, and CA-125 are associated with worse prognosis in advanced non-small-cell lung cancer (NSCLC)

    Clin Lung Cancer

    (2011)
  • CG Glasgow et al.

    CA-125 in disease progression and treatment of lymphangioleiomyomatosis

    Chest

    (2018)
  • ES Kim et al.

    The clinical significance of CA-125 in pulmonary tuberculosis

    Tuberculosis (Edinb)

    (2013)
  • AD Jackson

    Airway goblet-cell mucus secretion

    Trends Pharmacol Sci

    (2001)
  • J Goerke

    Pulmonary surfactant: functions and molecular composition

    Biochim Biophys Acta

    (1998)
  • E Ofek et al.

    Restrictive allograft syndrome post lung transplantation is characterized by pleuroparenchymal fibroelastosis

    Mod Pathol

    (2013)
  • LA Borthwick et al.

    Epithelial to mesenchymal transition (EMT) and airway remodelling after human lung transplantation

    Thorax

    (2009)
  • C Ward et al.

    Phenotype of airway epithelial cells suggests epithelial to mesenchymal cell transition in clinically stable lung transplant recipients

    Thorax

    (2005)
  • SS Weigt et al.

    Bronchiolitis obliterans syndrome: the Achilles' heel of lung transplantation

    Semin Respir Crit Care Med

    (2013)
  • L Levy et al.

    Epithelial cell death markers in bronchoalveolar lavage correlate with chronic lung allograft dysfunction subtypes and survival in lung transplant recipients-a single-center retrospective cohort study

    Transpl Int

    (2019)

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