Chronic lung allograft dysfunction is associated with an increased number of non-HLA antibodies

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is the major cause of adverse outcomes in lung transplant recipients. Multiple factors, such as infection, alloimmunity, and autoimmunity, may lead to CLAD. Here, we aim to examine the role of non-human leukocytes antigen (HLA) antibodies in CLAD in a large retrospective cohort.

METHODS

We analyzed non-HLA antibodies in the pre- and post-transplant sera of 226 (100 CLAD, 126 stable) lung transplant recipients from 5 centers, and we used a separate cohort to confirm our findings.

RESULTS

A panel of 18 non-HLA antibodies was selected for analysis based on their significantly higher positive rates in CLAD vs stable groups. The panel-18 non-HLA antibodies (n > 3) may be positive pre- or post-transplant; the risk for CLAD is higher in the latter. The presence of both non-HLA antibody and HLA donor-specific antibody (DSA) was associated with an augmented risk of CLAD (HR=25.09 [5.52-14.04], p < 0.001), which was higher than that for single-positive patients. In the independent confirmatory cohort of 61 (20 CLAD, 41 stable) lung transplant recipients, the risk for CLAD remained elevated in double-positive patients (HR=10.67 [0.98-115.68], p = 0.052). After adjusting for nonstandard immunosuppression, patients with double-positive DSA/Non-HLA antibodies had an elevated risk for graft loss (HR=2.53 [1.29-4.96], p = 0.007).

CONCLUSIONS

Circulating non-HLA antibodies (n > 3) were independently associated with a higher risk for CLAD. Furthermore, when non-HLA antibodies and DSA were detected concomitantly, the risk for CLAD and graft loss was significantly increased. These results show that humoral immunity to HLA and non-HLA antigens may contribute to CLAD development.

Case Report: Bilateral Lung Transplantation for Rapidly Progressive Undifferentiated Interstitial Lung Disease—A Cautionary Tale

Interstitial lung disease is fast becoming one of the most common indications for lung transplantation (LTx); however, LTx for Goodpasture's syndrome with pulmonary involvement has not been previously described in the literature. In this report, we outline the case of a young male with undifferentiated rapidly progressive interstitial lung disease who ultimately received a bilateral sequential LTx after deterioration requiring extracorporeal membrane oxygenation. The original disease soon recurred in the graft, and unfortunately, the patient did not survive. The diagnosis of Goodpasture's syndrome was made postmortem and was not clearly evident on examination of the native explanted tissue, nor was there an elevated titer of antiglomerular basement membrane antibodies during his initial work-up. We hypothesize that the donor and recipient's HLA profile made him more susceptible to aggressive disease. In hindsight, active Goodpasture's disease would have been a contraindication to proceed to transplantation. This case is a cautionary reminder of the high stakes of performing LTx without a certain diagnosis.

Airway oscillometry parameters in baseline lung allograft dysfunction: Associations from a multicenter study

BACKGROUND

Baseline lung allograft dysfunction (BLAD), the failure to achieve ≥80%-predicted spirometry after lung transplant (LTx), is associated with impaired survival. Physiologic abnormalities in BLAD are poorly understood. Airway oscillometry measures respiratory system mechanics and may provide insight into understanding the mechanisms of BLAD.

OBJECTIVES

This study aims to describe and measure the association between airway oscillometry parameters [Reactance (X_rs5, Ax), Resistance (R_rs5, R_rs5-19)] (1) stable LTx recipients, comparing those with normal spirometry and those with BLAD; and (2) in recipients with chronic lung allograft dysfunction (CLAD), comparing those with normal baseline spirometry and those with BLAD.

METHODS

A multi-center cross-sectional study was performed including bilateral LTx between January 2020 and June 2021. Participants performed concurrent airway oscillometry and spirometry. Multivariable logistic regression was performed to measure the association between oscillometry parameters and BLAD.

RESULTS

A total of 404 LTx recipients performed oscillometry and 253 were included for analysis. Stable allograft function was confirmed in 149 (50.2%) recipients (92 (61.7%) achieving normal spirometry and 57 (38.3%) with BLAD). Among stable LTx recipients, lower X_rs5 Z-Score (aOR 0.50 95% CI 0.37-0.76, p = 0.001) was independently associated with BLAD. CLAD was present in 104 (35.0%) recipients. Among recipients with CLAD, lower X_rs5 Z-Score (aOR 0.73 95% CI 0.56-0.95, p = 0.02) was associated with BLAD.

CONCLUSIONS

Oscillometry provides novel physiologic insights into mechanisms of BLAD. The independent association between X_rs5 and BLAD, in both stable recipients and those with CLAD suggests that respiratory mechanics, in particular abnormal elastance, is an important physiologic feature. Further longitudinal studies are needed to understand the trajectory of oscillometry parameters in relation to allograft outcomes.

Rescue Everolimus Post Lung Transplantation is Not Associated With an Increased Incidence of CLAD or CLAD-Related Mortality

Everolimus (EVE) has been used as a calcineurin inhibitor (CNI) minimization/ elimination agent or to augment immunosuppression in lung transplant recipients (LTR) with CNI-induced nephrotoxicity or neurotoxicity. The long-term evidence for survival and progression to chronic lung allograft dysfunction (CLAD) is lacking. The primary aim was to compare survival outcomes of LTR starting EVE-based immunosuppression with those remaining on CNI-based regimens. The secondary outcomes being time to CLAD, incidence of CLAD and the emergence of obstructive (BOS) or restrictive (RAS) phenotypes. Single center retrospective study of 91 LTR starting EVE-based immunosuppression matched 1:1 with LTR remaining on CNI-based immunosuppression. On multivariate analysis, compared to those remaining on CNI-based immunosuppression, starting EVE was not associated with poorer survival [HR 1.04, 95% CI: 0.67-1.61, p = 0.853], or a statistically significant faster time to CLAD [HR 1.34, 95% CI: 0.87-2.04, p = 0.182]. There was no difference in the emergence of CLAD (EVE, [n = 57, 62.6%] vs. CNI-based [n = 52, 57.1%], p = 0.41), or the incidence of BOS (p = 0.60) or RAS (p = 0.16) between the two groups. Introduction of EVE-based immunosuppression does not increase the risk of death or accelerate the progression to CLAD compared to CNI-based immunosuppression.

Survival and left ventricular dysfunction post lung transplantation for pulmonary arterial hypertension

PURPOSE

Bilateral lung transplantation for end-stage pulmonary arterial hypertension (PAH) is traditionally associated with higher early post-transplant mortality when compared with other indications. Changes in perioperative management, including the growing use of perioperative extracorporeal membrane oxygenation (ECMO) and an increased awareness of postoperative left ventricular dysfunction (LVD), have resulted in outcomes that are uncertain.

MATERIALS AND METHODS

We conducted a single-center, retrospective observational study at a lung transplantation center in Melbourne, Australia, from 2006 to 2019. ECMO use was categorized as preoperative, prophylactic, or rescue. Postoperative LVD was defined as a reduction in left ventricular function on echocardiography or using strict clinical criteria.

RESULTS

50 patients underwent lung transplantation for PAH. 12-month survival was 48/50 (96%). ECMO was used in 26 (52%) patients, and the use of prophylactic VA-ECMO increased over the study period. Postoperative LVD was diagnosed in 21 (42%) patients. 12-month survival and left ventricular function was no different between LVD and non-LVD groups.

CONCLUSIONS

This study showed that high survival rates can be achieved following lung transplantation for PAH. We found that ECMO utilization was common, and indications have changed over time. LVD was common but did not impact 12-month survival.

Review: immunosuppression for the lung transplant patient

Lung transplantation (LTx) has evolved significantly since its inception and the improvement in LTx outcomes over the last three decades has predominantly been driven by advances in immunosuppression management. Despite the lack of new classes of immunosuppression medications, immunosuppressive strategies have evolved significantly from a universal method to a more targeted approach, reflecting a greater understanding of the need for individualized therapy and careful consideration of all factors that are influenced by immunosuppression choice. This has become increasingly important as the demographics of lung transplant recipients have changed over time, with older and more medically complex candidates being accepted and undergoing LTx. Furthermore, improved survival post lung transplant has translated into more immunosuppression related comorbidities long-term, predominantly chronic kidney disease (CKD) and malignancy, which has required further nuanced management approaches. This review provides an update on current traditional lung transplant immunosuppression strategies, with modifications based on pre-existing recipient factors and comorbidities, peri-operative challenges and long term complications, balanced against the perpetual challenge of chronic lung allograft dysfunction (CLAD). As we continue to explore and understand the complexity of LTx immunology and the interplay of different factors, immunosuppression strategies will require ongoing critical evaluation and personalization in order to continue to improve lung transplant outcomes.

A GLIMmer of insight into lung transplant nutrition: Enhanced detection of malnutrition in lung transplant patients using the GLIM criteria

BACKGROUND & AIMS

The Global Leadership Initiative on Malnutrition (GLIM) is a novel framework for diagnosing malnutrition and requires evaluation in wide-ranging clinical settings. This study aimed to assess the prevalence of malnutrition and its phenotypic characteristics among lung transplantation (LTx) candidates comparing GLIM to International Classification of Diseases, 10th Revision (ICD-10) criteria.

METHODS

A retrospective analysis was conducted of all adult patients assessed for LTx in a one-year period. Phenotypic criteria included body mass index (BMI), unintentional loss of weight (LOW) over a 12-month period and fat-free mass index (FFMI) using bioelectrical impedance analysis (BIA). Systemic inflammation associated with severe end-stage lung disease met GLIM's etiological criterion. Diagnosis of malnutrition, and its severity, were classified according to each of GLIM and ICD-10.

RESULTS

Of 130 patients, 112 (86%) had all data to classify malnutrition. Malnutrition prevalence according to GLIM was 59%, which was markedly greater than using ICD-10 criteria (26%). Half of the LTx patients were moderately malnourished using GLIM, compared to 19% using ICD-10. A similar proportion were severely malnourished using GLIM (9%) and ICD-10 (7%). Fat-free mass (FFM) depletion (47% of all patients) was a major contributor to GLIM-malnutrition. Over 60% of LTx patients with GLIM-malnutrition were not detected as malnourished using ICD-10 criteria.

CONCLUSION

Malnutrition diagnosis using GLIM was higher than using ICD-10 in LTx patients, primarily attributable to the incorporation of quantitative evaluation of FFM depletion. This highlights the utility of the GLIM framework and the importance of including body composition in malnutrition assessment.

Outcomes Of Non-Cystic Fibrosis Related Bronchiectasis Post Lung Transplantation

BACKGROUND

Lung transplantation is a recognised treatment for end-stage lung disease due to bronchiectasis. Non-CF bronchiectasis and CF are often combined into one cohort, however outcomes for non-CF bronchiectasis patients varies between centres, and in comparison to those for CF.

AIMS

To compare lung transplantation mortality and morbidity of bronchiectasis (non-CF) patients to those with CF and other indications.

METHODS

Retrospective analysis of patients undergoing lung transplantation between 01 January 2008-31 December 2013. Time to and cause of lung allograft loss was censored on 01 April 2018. A case-note review was conducted on a sub-group of 78 patients, to analyse hospital admissions as a marker of morbidity.

RESULTS

341 patients underwent lung transplantation, 22 (6%) had bronchiectasis compared to 69 (20%) with CF. The 5-year survival for the bronchiectasis group was 32%, compared to CF 69%, obstructive lung disease (OLD) 64%, pulmonary hypertension 62% and ILD 55% (p = 0.008). Lung allograft loss due to CLAD with predominant infection was significantly higher in the bronchiectasis group at 2 years. The rate of acute admissions was 2.24 higher in the bronchiectasis group when compared to OLD (p = 0.01). Patients with bronchiectasis spent 45.81 days in hospital per person year after transplantation compared with 18.21 days for CF.

CONCLUSIONS

Bronchiectasis patients in this study had a lower 5-year survival and poorer outcomes in comparison to other indications including CF. Bronchiectasis should be considered a separate entity to CF in survival analysis. This article is protected by copyright. All rights reserved.

Long-term management of elderly patients taking immunosuppressive medications

BACKGROUND

General practitioners are increasingly likely to encounter elderly patients who are receiving immunosuppressants for the management of autoimmune diseases or solid organ transplants.

OBJECTIVE

The aim of this article is to provide an overview of the long-term management of the elderly patient treated with immunosuppressants. Recommendations for monitoring, preventing and managing adverse effects of immunosuppressants are summarised.

DISCUSSION

Elderly patients prescribed immunosuppressants may present a number of unique challenges. Immunosenescence, altered pharmacokinetics and the presence of multiple comorbidities can all affect response to immunosuppressants. Through close collaboration with tertiary care providers and regular screening, the general physician is well placed to recognise medication-related complications.

Molecular T-cell‒mediated rejection in transbronchial and mucosal lung transplant biopsies is associated with future risk of graft loss

BACKGROUND

We previously developed molecular assessment systems for lung transplant transbronchial biopsies (TBBs) with high surfactant and bronchial mucosal biopsies, identifying T-cell‒mediated rejection (TCMR) on the basis of the expression of rejection-associated transcripts, but the relationship of rejection to graft loss is unknown. This study aimed to develop molecular assessments for TBBs and mucosal biopsies and to establish the impact of molecular TCMR on graft survival.

METHODS

We used microarrays and machine learning to assign TCMR scores to an expanded cohort of 457 TBBs (367 high surfactant plus 90 low surfactant) and 314 mucosal biopsies. We tested the score agreement between TBB-TBB, mucosal-mucosal, and TBB-mucosal biopsy pairs in the same patient. We also assessed the association of molecular TCMR scores with graft loss (death or retransplantation) and compared it with the prognostic associations for histology and donor-specific antibodies.

RESULTS

The molecular TCMR scores assigned in all the TBBs performed similarly to those in high-surfactant TBBs, indicating that variation in alveolation in TBBs does not prevent the detection of TCMR. Mucosal biopsy pieces showed less piece-to-piece variation than TBBs. TCMR scores in TBBs agreed with those in mucosal biopsies. In both TBBs and mucosal biopsies, molecular TCMR was associated with graft loss, whereas histologic rejection and donor-specific antibodies were not.

CONCLUSIONS

Molecular TCMR can be detected in TBBs regardless of surfactant and in mucosal biopsies, which show less variability in the sampled tissue than TBBs. On the basis of these findings, molecular TCMR appears to be an important predictor of the risk of future graft failure.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02812290.

Consequences of donor-derived passengers (pathogens, cells, biological molecules and proteins) on clinical outcomes

It is recognized that donor factors contribute to lung transplant outcomes. Recent observations and studies have started to elucidate potential mechanisms behind explaining these observations. This perspective piece summarizes evolving lung transplant literature on the subject, focusing on donor "passenger" organisms, cells, hormones, and proteins transferred to the recipient. Many extrinsic and intrinsic donor features or properties have important consequences for subsequent allograft function in the recipient. Potentially, a better understanding of these features may provide useful novel therapeutic targets to enhance allograft outcomes.

Donation after Brain Death versus Donation after Circulatory Death: Lung Donor Management Issues

Lung transplantation (LTx) has traditionally been limited by a lack of suitable donor lungs. With the recognition that lungs are more robust than initially thought, the size of the donor pool of available lungs has increased dramatically in the past decade. Donation after brain death (DBD) and donation after circulatory death (DCD) lungs, both ideal and extended are now routinely utilized. DBD lungs can be damaged. There are important differences in the public's understanding, legal and consent processes, intensive care unit strategies, lung pathophysiology, logistics, and potential-to-actual donor conversion rates between DBD and DCD. Notwithstanding, the short- and long-term outcomes of LTx from any of these DBD versus DCD donor scenarios are now similar, robust, and continue to improve. Large audits suggest there remains a large untapped pool of DCD (but not DBD) lungs that may yet further dramatically increase lung transplant numbers. Donor scoring systems that might predict the donor conversion rates and lung quality, the role of ex vivo lung perfusion as an assessment and lung resuscitation tool, as well as the potential of donor lung quality biomarkers all have immense promise for the clinical field.

Domiciliary non-invasive ventilation post lung transplantation

BACKGROUND AND OBJECTIVE

The benefits of domiciliary non-invasive ventilation (NIV) post lung transplantation (LTx) have not previously been described. This was a single-centre retrospective audit of patients requiring domiciliary NIV post-LTx. Our aim was to describe indications for NIV and outcomes in chronic lung allograft dysfunction (CLAD) and diaphragmatic palsy.

METHODS

All patients requiring domiciliary NIV post-LTx between 2010 and June 2016 were assessed. NIV indications, respiratory function and patient outcomes were collected.

RESULTS

Out of 488 LTx recipients, 20 patients were identified as requiring NIV over the 6.5-year study period. The most common indications for NIV were CLAD and diaphragmatic palsy. Hypercapnia improved significantly with NIV. Patient outcomes were poor with nine (45%) patients dying, four (20%) undergoing redo-LTx, four (20%) continuing domiciliary NIV and only three (15%) patients weaned off NIV.

CONCLUSION

This is the first case series to describe the use of domiciliary NIV post-LTx. Patients commenced on NIV post-LTx had severely impaired lung function and severe hypercapnia. Patients with diaphragmatic palsy often recovered. The mortality rate was high in chronic allograft dysfunction.