Prognostic significance of early pulmonary function changes after onset of chronic lung allograft dysfunction

COVID-19 infection is mild and has minimal impact on lung function in well vaccinated and widely treated lung transplant recipients

BACKGROUND

COVID-19 has become a common infection affecting lung transplant recipients (LTR), who are at high risk for poor outcomes. Outcomes early in the pandemic were poor, but since the rollout of vaccination and novel COVID-19 treatments, outcomes of LTR have not been well described. Our aim was to evaluate the effect of COVID-19 on the clinical course and lung function trajectory in an Australian cohort of LTR.

METHODS

Data were retrospectively collected from LTR with confirmed COVID-19 managed at Alfred Health, between August 2020 and December 2022. Baseline demographics, COVID-19 disease details (including severity) and spirometry pre- and postinfection have been analyzed.

RESULTS

A total of 279 LTR were included. The cohort was comorbid, but well vaccinated, with 275/279 (98.6%) having ≥2 COVID-19 vaccines at symptom onset. Severe disease occurred in only 17 cases (6%) and overall mortality was very low (4%). Prompt treatment with antivirals, particularly remdesevir (OR 0.18, 95% CI 0.04-0.81, p = 0.02) and vaccination (OR 0.24, CI 0.08-0.81, p = 0.01), was protective. There was not a clinically significant drop in lung function post-COVID-19 with the median absolute decline in forced expiratory volume (FEV1) being 40 ml (IQR 5-120 ml, p < 0.001), with a decline of >10% occurring in only 42 patients (17%). After multivariate adjustment, only rejection before COVID-19 was significantly associated with FEV1 decline afterward (OR 3.74, 1.12-11.86, p = 0.03).

CONCLUSIONS

In our highly COVID-19 vaccinated, promptly treated LTR, the majority of COVID-19 infections were mild and did not result in a clinically significant decline in lung function.

Extracorporeal photopheresis (ECP) in the treatment of chronic lung allograft dysfunction (CLAD): a prospective, multicentre, open-label, randomised controlled trial studying the addition of ECP to standard care in the treatment of bilateral lung transplant patients with CLAD (E-CLAD UK)

BACKGROUND

Long-term survival after lung transplantation is limited compared with other organ transplants. The main cause is development of progressive immune-mediated damage to the lung allograft. This damage, which can develop via multiple immune pathways, is captured under the umbrella term chronic lung allograft dysfunction (CLAD). Despite the availability of powerful immunosuppressive drugs, there are presently no treatments proven to reverse or reliably halt the loss of lung function caused by CLAD. The aim of the E-CLAD UK trial is to determine whether the addition of immunomodulatory therapy, in the form of extracorporeal photopheresis (ECP), to standard care is more efficacious at stabilising lung function in CLAD compared with standard care alone.

METHODS AND ANALYSIS

E-CLAD UK is a Phase II clinical trial of an investigational medicinal product (Methoxsalen) delivered to a buffy coat prepared via an enclosed ECP circuit. Target recruitment is 90 bilateral lung transplant patients identified as having CLAD and being treated at one of the five UK adult lung transplant centres. Participants will be randomised 1:1 to intervention plus standard of care, or standard of care alone. Intervention will comprise nine ECP cycles spread over 20 weeks, each course involving two treatments of ECP on consecutive days. All participants will be followed up for a period of 24 weeks.The primary outcome is lung function stabilisation derived from change in forced expiratory volume in one second and forced vital capacity at 12 and 24 weeks compared with baseline at study entry. Other parameters include change in exercise capacity, health-related quality of life and safety. A mechanistic study will seek to identify molecular or cellular markers linked to treatment response and qualitative interviews will explore patient experiences of CLAD and the ECP treatment.A patient and public advisory group is integral to the trial from design to implementation, developing material to support the consent process and interview materials.

ETHICS AND DISSEMINATION

The East Midlands-Derby Research Ethics Committee has provided ethical approval (REC 22/EM/0218). Dissemination will be via publications, patient-friendly summaries and presentation at scientific meetings.

TRIAL REGISTRATION NUMBER

EudraCT number 2022-002659-20; ISRCTN 10615985.

Prognostic Value of Chest CT Findings at BOS Diagnosis in Lung Transplant Recipients

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) after lung transplantation is characterized by fibrotic small airway remodeling, recognizable on high-resolution computed tomography (HRCT). We studied the prognostic value of key HRCT features at BOS diagnosis after lung transplantation.

METHODS

The presence and severity of bronchiectasis, mucous plugging, peribronchial thickening, parenchymal anomalies, and air trapping, summarized in a total severity score, were assessed using a simplified Brody II scoring system on HRCT at BOS diagnosis, in a cohort of 106 bilateral lung transplant recipients transplanted between January 2004 and January 2016. Obtained scores were subsequently evaluated regarding post-BOS graft survival, spirometric parameters, and preceding airway infections.

RESULTS

A high total Brody II severity score at BOS diagnosis (P = 0.046) and high subscores for mucous plugging (P = 0.0018), peribronchial thickening (P = 0.0004), or parenchymal involvement (P = 0.0121) are related to worse graft survival. A high total Brody II score was associated with a shorter time to BOS onset (P = 0.0058), lower forced expiratory volume in 1 s (P = 0.0006) forced vital capacity (0.0418), more preceding airway infections (P = 0.004), specifically with Pseudomonas aeruginosa (P = 0.002), and increased airway inflammation (P = 0.032).

CONCLUSIONS

HRCT findings at BOS diagnosis after lung transplantation provide additional information regarding its underlying pathophysiology and for future prognosis of graft survival.

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

Background

Chronic lung allograft dysfunction (CLAD) is defined by a progressive loss of FEV1 and is associated with premature mortality. The aim of this study was to investigate the direct association between FEV1 decline and risk of mortality in patients after lung transplantation (LTx).

Methods

10-year follow up data from lung transplant recipients participating in randomized placebo-controlled clinical trial investigating the role of liposomal Cyclosporine A for inhalation (L-CsA-i) in the prevention of bronchiolitis obliterans syndrome (NCT01334892) was used. The association between the course of FEV1 over time and the risk of mortality was assessed using joint modeling and Cox regression analysis.

Results

A total of 130 patients were included. Predictors of FEV1 decline were a higher absolute FEV1 at baseline and male sex. The joint model analysis indicated a significant association of change of FEV1 and risk of mortality (p < 0.001), with a predicted 3.4% increase in mortality risk for each 1% decline in FEV1. Significant predictors of a progressive phenotype were single LTx and treatment with placebo (as opposed to L-CsA-i). At the end of follow-up, 82 patients (63.1%) were still alive. Cox regression analyses for mortality identified only single LTx as a predictor of higher risk.

Conclusion

Based on our observation of a close association between FEV1 and mortality over a period of 10 years we suggest FEV1 as a valid predictor of mortality and a suitable surrogate endpoint in the investigation of early interventions.

Novel biomarkers of chronic lung allograft dysfunction: is there anything reliable?

PURPOSE OF REVIEW

Chronic lung allograft dysfunction (CLAD) remains a major barrier preventing long-term survival following lung transplantation. As our clinical knowledge regarding its definition and presentation has significantly improved over the last years, adequate biomarkers to predict development of CLAD, phenotype of CLAD or prognosis post-CLAD diagnosis are definitely needed.

RECENT FINDINGS

Radiological and physiological markers are gradually entering routine clinical practice. In-depth investigation of biological samples including broncho-alveolar lavage, biopsy and serum has generated potential biomarkers involved in fibrogenesis, airway injury and inflammation but none of these are universally accepted or implemented although progress has been made, specifically regarding donor-derived cell-free DNA and donor-specific antibodies.

SUMMARY

Although a lot of promising biomarkers have been put forward, a very limited number has made it to routine clinical practice. Nevertheless, a biomarker that leads to earlier detection or more adequate disease phenotyping would advance the field enormously.

Multi-omics profiling predicts allograft function after lung transplantation

RATIONALE

Lung transplantation is the ultimate treatment option for patients with end-stage respiratory diseases but bears the highest mortality rate among all solid organ transplantations due to chronic lung allograft dysfunction (CLAD). The mechanisms leading to CLAD remain elusive due to an insufficient understanding of the complex post-transplant adaptation processes.

OBJECTIVES

To better understand these lung adaptation processes after transplantation and to investigate their association with future changes in allograft function.

METHODS

We performed an exploratory cohort study of bronchoalveolar lavage samples from 78 lung recipients and donors. We analysed the alveolar microbiome using 16S rRNA sequencing, the cellular composition using flow cytometry, as well as metabolome and lipidome profiling.

MEASUREMENTS AND MAIN RESULTS

We established distinct temporal dynamics for each of the analysed data sets. Comparing matched donor and recipient samples, we revealed that recipient-specific as well as environmental factors, rather than the donor microbiome, shape the long-term lung microbiome. We further discovered that the abundance of certain bacterial strains correlated with underlying lung diseases even after transplantation. A decline in forced expiratory volume during the first second (FEV1) is a major characteristic of lung allograft dysfunction in transplant recipients. By using a machine learning approach, we could accurately predict future changes in FEV1 from our multi-omics data, whereby microbial profiles showed a particularly high predictive power.

CONCLUSION

Bronchoalveolar microbiome, cellular composition, metabolome and lipidome show specific temporal dynamics after lung transplantation. The lung microbiome can predict future changes in lung function with high precision.

Graft dysfunction and rejection of lung transplant, a review on diagnosis and management

Introduction

Lung transplantation has proven to be an effective treatment option for end‐stage lung disease. However, early and late complications following transplantation remain significant causes of high mortality.

Objectives

In this review, we focus on the time of onset in primary graft dysfunction and rejection complications, as well as emphasize the role of imaging manifestations and pathological features in early diagnosis, thus assisting clinicians in the early detection and treatment of posttransplant complications and improving patient quality of life and survival.

Data source

We searched electronic databases such as PubMed, Web of Science, and EMBASE. We used the following search terms: lung transplantation complications, primary graft dysfunction, acute rejection, chronic lung allograft dysfunction, radiological findings, and diagnosis and treatment.

Conclusion

Primary graft dysfunction, surgical complications, immune rejection, infections, and neoplasms represent major posttransplant complications. As the main posttransplant survival limitation, chronic lung allograft dysfunction has a characteristic imaging presentation; nevertheless, the clinical and imaging manifestations are often complex and overlap, so it is essential to understand the temporal evolution of these complications to narrow the differential diagnosis for early treatment to improve prognosis.

Early and late complications after lung transplantation remain essential causes of high mortality. In this review, we focus on the timing of the onset of primary graft dysfunction and rejection complications and highlight the role of imaging manifestations and clinicopathologic features in early diagnosis, thus assisting clinicians in the early detection and treatment of posttransplant complications and improving patient quality of life and survival.

Twelve-month effects of everolimus on renal and lung function in lung transplantation: differences in chronic lung allograft dysfunction phenotypes

Background:

Chronic lung allograft dysfunction (CLAD), a complication affecting the survival of lung transplanted patients, includes two clinical phenotypes: bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). Everolimus is used in CLAD because of its antiproliferative mechanism. In lung transplant patients treated with everolimus, the clinical course of renal and lung function has not yet been assessed systematically in CLAD, BOS and RAS patients for more than 6 months.

Methods:

We retrospectively evaluated the 12-month follow-up of renal and lung function of lung-transplanted patients switched to everolimus and evaluated the reduction in immunosuppressant dosage (ISD) and mortality. Subgroups were based on indication for everolimus treatment: CLAD and non-CLAD patients, BOS and RAS among CLAD patients.

Results:

We included 26 patients, 17 with CLAD (10 BOS, seven RAS). After 1 year from the everolimus switch, we observed renal function improvement (serum creatinine −17%, estimated glomerular filtration rate +24%) and stable pulmonary function [forced expiratory volume in the first second (FEV₁) −0.5%, forced vital capacity (FVC) +0.05%]. RAS patients had progressive functional loss, whereas BOS patients had FEV₁ improvement and FVC stability. All-cause mortality was higher in the CLAD versus non-CLAD group (41% versus 11%), without differences between BOS and RAS patients (p > 0.05). All patients had significant and persistent ISD reduction.

Conclusion:

Lung transplant patients treated with everolimus had improvements in renal function and reduced ISD. We observed sustained improvements in lung function for CLAD related to BOS subgroup results, whereas RAS confirmed the 1-year worsening functional trend. Data seem to suggest one more piece of the puzzle in CLAD phenotyping.

Longitudinal lung function measurements in single lung transplant recipients with chronic lung allograft dysfunction

BACKGROUND

Phenotyping chronic lung allograft dysfunction (CLAD) in single lung transplant (SLTX) recipients is challenging. The aim of this study was to assess the diagnostic and prognostic value of longitudinal lung function tests in SLTX recipients with CLAD.

METHODS

A total of 295 SLTX recipients were analyzed and stratified according to native lung physiology. In addition to spirometry, measurements of static lung volumes and lung capacities were used to phenotype patients and to assess their prognostic value. Outcome was survival after CLAD onset. Patients with insufficient clinical information were excluded (n = 71).

RESULTS

Of 224 lung transplant recipients, 105 (46.9%) developed CLAD. Time to CLAD onset (hazard ratio [HR]: 0.82, 95% CI: 0.74-0.90; p < 0.001), severity of CLAD at onset (HR: 0.97, 95% CI: 0.94-0.99; p = 0.009), and progression after onset of CLAD (HR: 1.03, 95% CI: 1.00-1.05; p = 0.023) were associated with outcome. Phenotypes at onset were bronchiolitis obliterans syndrome (BOS) (59.1%), restrictive allograft syndrome (RAS) (12.4%), mixed phenotype (6.7%), and undefined phenotype (21.9%). Survival estimates differed significantly between phenotypes (p = 0.004), with RAS and mixed phenotype being associated with the worst survival, followed by BOS and undefined phenotype. Finally, a higher hazard for mortality was noticed for RAS (HR: 2.34, 95% CI: 0.99-5.52; p = 0.054) and mixed phenotype (HR: 3.30, 95% CI: 1.20-9.11; p = 0.021) while controlling for time to CLAD onset and severity of CLAD at onset.

CONCLUSIONS

Phenotyping CLAD in SLTX remains challenging with a high number of patients with an undefined phenotype despite comprehensive lung function testing. However, phenotyping is of prognostic value. Furthermore, early, severe, and progressive CLADs are associated with worse survival.

Bronchoalveolar bile acid and inflammatory markers to identify high-risk lung transplant recipients with reflux and microaspiration

BACKGROUND

Gastroesophageal reflux disease (GERD) is a risk factor for chronic lung allograft dysfunction. Bile acids-putative markers of gastric microaspiration-and inflammatory proteins in the bronchoalveolar lavage (BAL) have been associated with chronic lung allograft dysfunction, but their relationship with GERD remains unclear. Although GERD is thought to drive chronic microaspiration, the selection of patients for anti-reflux surgery lacks precision. This multicenter study aimed to test the association of BAL bile acids with GERD, lung inflammation, allograft function, and anti-reflux surgery.

METHODS

We analyzed BAL obtained during the first post-transplant year from a retrospective cohort of patients with and without GERD, as well as BAL obtained before and after Nissen fundoplication anti-reflux surgery from a separate cohort. Levels of taurocholic acid (TCA), glycocholic acid, and cholic acid were measured using mass spectrometry. Protein markers of inflammation and injury were measured using multiplex assay and enzyme-linked immunosorbent assay.

RESULTS

At 3 months after transplantation, TCA, IL-1β, IL-12p70, and CCL5 were higher in the BAL of patients with GERD than in that of no-GERD controls. Elevated TCA and glycocholic acid were associated with concurrent acute lung allograft dysfunction and inflammatory proteins. The BAL obtained after anti-reflux surgery contained reduced TCA and inflammatory proteins compared with that obtained before anti-reflux surgery.

CONCLUSIONS

Targeted monitoring of TCA and selected inflammatory proteins may be useful in lung transplant recipients with suspected reflux and microaspiration to support diagnosis and guide therapy. Patients with elevated biomarker levels may benefit most from anti-reflux surgery to reduce microaspiration and allograft inflammation.

Chronic lung allograft dysfunction: light at the end of the tunnel?

PURPOSE OF REVIEW

Chronic lung allograft dysfunction (CLAD) has been recently introduced as an umbrella-term encompassing all forms of chronic pulmonary function decline posttransplant with bronchiolitis obliterans syndrome and restrictive allograft syndrome as the most important subtypes. Differential diagnosis and management, however, remains complicated.

RECENT FINDINGS

Herein, we provide an overview of the different diagnostic criteria (pulmonary function, body plethysmography and radiology) used to differentiate bronchiolitis obliterans syndrome and restrictive allograft syndrome, their advantages and disadvantages as well as potential problems in making an accurate differential diagnosis. Furthermore, we discuss recent insights in CLAD management and treatment and advances in the search for accurate biomarkers of CLAD.

SUMMARY

Careful dissection of CLAD phenotypes is of utmost importance to assess patient prognosis, but uniform diagnostic criteria are desperately needed. There is a long way ahead, but the first steps towards this goal are now taken; tailored individualized therapy will be the golden standard to treat CLAD in the future, but randomized placebo-controlled and multicentre trials are needed to identify new and powerful therapeutic agents.