Surrogate markers and risk factors for chronic lung allograft dysfunction

Optimization of Transbronchial Cryobiopsy in Lung Transplant Recipients

BACKGROUND

Previous studies suggest that transbronchial lung biopsy using a cryoprobe is superior to transbronchial lung biopsy using forceps for evaluating lung grafts, although the technique can be associated an increase in complications. Because cryoprobe experience is limited, assessment of a greater number of cases is warranted. This prospective study evaluates the diagnostic yield, complications, and risk factors associated with the cryoprobe technique.

METHODS

From April 2013 to April 2016, 321 consecutive cryoprobe transbronchial biopsies were indicated in single or bilateral lung transplant patients with acute or chronic clinical lung injury or in asymptomatic patients before hospital discharge after lung transplantation.

RESULTS

With a mean of 4.32 lung parenchyma specimens per procedure, adequate alveolar lung parenchyma was obtained in 96.6% (84.27 ± 44.14 mm²) of cases. Obtaining at least 4 samples increased the histological diagnostic certainty (P < .001). Moderate to severe bleeding was observed in 7.48% of patients and was significantly more frequent in patients with unilateral transplantation (odds ratio, 0.10; 95% confidence interval, 0.02-0.30; P < .001) and in those with high blood pressure during scanning (odds ratio, 0.31; 95% confidence interval, 0.12-0.86; P = .019). Pneumothorax was observed in 7.7% of the patients, but only 3.7% of these patients required pleural drainage.

CONCLUSIONS

Obtaining 4 or more cryobiopsy samples is valuable and safe for lung allograft monitoring. Being a recipient of a unilateral lung transplant or having arterial hypertension during bronchoscopy seem to be risk factors associated with increased bleeding.

High circulating CD4+CD25hiFOXP3+ T-cell sub-population early after lung transplantation is associated with development of bronchiolitis obliterans syndrome

BACKGROUND

Chronic bronchiolitis obliterans syndrome (BOS) remains a major limitation for long-term survival after lung transplantation. The immune mechanisms involved and predictive biomarkers have yet to be identified. The purpose of this study was to determine whether peripheral blood T-lymphocyte profile could predict BOS in lung transplant recipients.

METHODS

An in-depth profiling of CD4⁺ and CD8⁺ T cells was prospectively performed on blood cells from stable (STA) and BOS patients with a longitudinal follow-up. Samples were analyzed at 1 and 6 months after transplantation, at the time of BOS diagnosis, and at an intermediate time-point at 6 to 12 months before BOS diagnosis.

RESULTS

Although no significant difference was found for T-cell compartments at BOS diagnosis or several months beforehand, we identified an increase in the CD4⁺CD25^hiFoxP3⁺ T-cell sub-population in BOS patients at 1 and 6 months after transplantation (3.39 ± 0.40% vs 1.67 ± 0.22% in STA, p < 0.001). A CD4⁺CD25^hiFoxP3⁺ T-cell threshold of 2.4% discriminated BOS and stable patients at 1 month post-transplantation. This was validated on a second set of patients at 6 months post-transplantation. Patients with a proportion of CD4⁺CD25^hiFoxP3⁺ T cells up to 2.4% in the 6 months after transplantation had a 2-fold higher risk of developing BOS.

CONCLUSIONS

This study is the first to report an increased proportion of circulating CD4⁺CD25^hiFoxP3⁺ T cells early post-transplantation in lung recipients who proceed to develop BOS within 3 years, which supports its use as a BOS predictive biomarker.

[Specific infections in organ transplantation]

This article is concerned with the important topic of infections associated with organ transplantation and includes a discussion on four subtopics. The first section describes the current options in the prevention and therapy of viral hepatitis in association with liver transplantation. Infections with hepatitis B, C, D (delta) and E are discussed with special emphasis on the interferon-free treatment of hepatitis C with the new antiviral drugs.The second section deals with Pseudomonas aeruginosa (PA) infections following lung transplantation (LuTx), which is one of the most frequently detected pathogens in the airway after LuTx. Patients with cystic fibrosis are particularly affected. This is important because studies have shown a clear correlation between chronic PA infections after LuTx and development of chronic transplant failure. Even if the data are still sparse, recommendations on prevention and therapeutic strategies are given. The theme of the third section is the high importance of viral infections after kidney transplantation. In addition to acquired infections, the transplanted organ as well as the recipient can be the source of the infection. The better the transplanted organ is tolerated under moderate immunosuppression, the less common and severe virus infections are. The focus of this section is on three common pathogens: cytomegalovirus, polyomavirus BK and hepatitis viruses.The final section deals with Aspergillus infections following transplantation of various organs. In this context Aspergillus spp. are one of the most commonly occurring fungal diseases. The epidemiology, risk factors, diagnostics, prophylaxis and therapy of invasive aspergillosis are presented.

Lung Transplantation for Idiopathic Pulmonary Fibrosis

Despite advances in the development of novel pharmaceutical agents to treat idiopathic pulmonary fibrosis (IPF), there are no medical therapies known to resolve fibrosis or improve lung function in IPF. Therefore, lung transplantation remains the only life-saving therapy available to treat patients with IPF. However, a shortage of suitable donor organs limits the number of affected individuals who can undergo this procedure, and this shortage highlights the need to allocate donor lungs to those who are in the greatest need of a life-saving therapy yet ensure that those who undergo transplantation will have a reasonable expectation of long-term survival. Still, outcomes remain relatively poor for many patients after lung transplantation, although a sizable minority of patients can enjoy long-term survival after lung transplantation.

Interstitial pneumonitis and the risk of chronic allograft rejection in lung transplant recipients

BACKGROUND

The presence of interstitial pneumonitis (IP) on surveillance lung biopsy specimens in lung transplant recipients is poorly described, and its impact on posttransplant outcomes is not established. The following study assessed the association of posttransplant IP with the development of bronchiolitis obliterans syndrome (BOS).

METHODS

We examined all recipients of primary cadaveric lung transplants at our institution between January 1, 2000, and December 31, 2007 (N = 145). Patients had bronchoscopies with BAL, and transbronchial biopsies performed for surveillance during posttransplant months 1, 3, 6, and 12 as well as when clinically indicated. Patients were given a diagnosis of IP if, in the absence of active infection and organizing pneumonia, they showed evidence of interstitial inflammation and fibrosis on two or more biopsy specimens.

RESULTS

IP was a significant predictor of BOS (OR, 7.84; 95% CI, 2.84-21.67; P < .0001) and was significantly associated with time to development of BOS (hazard ratio, 3.8; 95% CI, 1.93-7.39; P = .0001) within the first 6 years posttransplant. The presence of IP did not correlate with a significantly higher risk of mortality or time to death. There was no association between the presence of IP and the development of or time to acute rejection.

CONCLUSIONS

The presence of IP on lung transplant biopsy specimens suggests an increased risk for BOS, which is independent of the presence of acute cellular rejection.

Managing complications following lung transplantation

Lung transplantation has become a proven therapeutic option for patients with end-stage lung disease, extending life and providing improved quality of life to those who otherwise would continue to be breathless and oxygen-dependent. Over the past 20 years, considerable experience has been gained in understanding the multitude of medical and surgical issues that impact upon patient survival. Today, clinicians have an armamentarium of tools to manage diverse problems such as primary graft dysfunction, acute and chronic allograft rejection, airway anastomotic issues, infectious complications, renal dysfunction, diabetes and osteoporosis, hematological and gastrointestinal problems, malignancy, and other unique issues that confront immunosuppressed solid organ transplant recipients.

Spirometrically significant acute rejection increases the risk for BOS and death after lung transplantation

Acute rejection (AR) is a common complication following lung transplantation and is an established risk factor for bronchiolitis obliterans syndrome (BOS). AR clinical presentation varies considerably and is sometimes associated with an acute decrease in forced expiratory volume in 1 s (FEV1). We hypothesized that lung transplant recipients who experience such spirometrically significant AR (SSAR), as defined by a ≥10% decline in FEV1 relative to the prior pulmonary function test, are subsequently at increased risk for BOS and worse overall survival. In a large single center cohort (n = 339), SSAR occurred in 79 subjects (23%) and significantly increased the risk for BOS (p < 0.0001, HR = 3.2, 95% CI 2.3-4.6) and death (p = 0.0001, HR = 2.3, 95% CI 1.5-3.5). These effects persisted after multivariate adjustment for pre-BOS AR and lymphocytic bronchiolitis burden. An analysis of the subset of patients who experienced severe SSAR (≥20% decline in FEV1) resulted in even greater hazards for BOS and death. Thus, we demonstrate a novel physiological measure that allows discrimination of patients at increased risk for worse posttransplant outcomes. Further studies are needed to determine mechanisms of airflow impairment and whether aggressive clinical interventions could improve post-SSAR outcomes.

Mesenchymal stromal cells in bronchoalveolar lavage as predictors of bronchiolitis obliterans syndrome

RATIONALE

Bronchoalveolar lavage fluid (BAL) from human lung allografts demonstrates the presence of a multipotent mesenchymal stromal cell population. However, the clinical relevance of this novel cellular component of BAL and its association with bronchiolitis obliterans syndrome (BOS), a disease marked by progressive airflow limitation secondary to fibrotic obliteration of the small airways, remains to be determined.

OBJECTIVES

In this study we investigate the association of number of mesenchymal stromal cells in BAL with development of BOS in human lung transplant recipients.

METHODS

Mesenchymal colony-forming units (CFUs) were quantitated in a cohort of 405 BAL samples obtained from 162 lung transplant recipients. Poisson generalized estimating equations were used to determine the predictors of BAL mesenchymal CFU count.

MEASUREMENTS AND MAIN RESULTS

Higher CFU counts were noted early post-transplantation; time from transplant to BAL of greater than 3 months predicted 0.4-fold lower CFU counts (P = 0.0001). BOS diagnosis less than or equal to 365 days before BAL was associated with a 2.11-fold higher CFU count (P = 0.02). There were 2.62- and 2.70-fold higher CFU counts noted in the presence of histologic diagnosis of bronchiolitis obliterans (P = 0.05) and organizing pneumonia (0.0003), respectively. In BAL samples obtained from BOS-free patients greater than 6 months post-transplantation (n = 173), higher mesenchymal CFU counts (≥10) significantly predicted BOS onset in both univariate (hazard ratio, 5.61; 95% CI, 3.03-10.38; P < 0.0001) and multivariate (hazard ratio, 5.02; 95% CI, 2.40-10.51; P < 0.0001) Cox regression analysis.

CONCLUSIONS

Measurement of mesenchymal CFUs in the BAL provides predictive information regarding future BOS onset.

Optimizing post-transplant outcomes in lung transplantation

Lung transplant recipients are at risk of numerous complications, which range from early events, such as primary graft dysfunction, to late events, including opportunistic infection or graft loss caused by chronic rejection. Although lung transplantation is often the only therapeutic option that can improve quality of life and prolong survival for many forms of end-stage lung disease, survival following lung transplantation is significantly worse than survival following transplantation of other solid organs. Carefully choosing potential recipients for listing, maximizing the likelihood that donor organs will function well following implantation, appropriate use of immunosuppressive agents to prevent allograft rejection, prophylactic or pre-emptive strategies to prevent allograft infection and appropriate surveillance to detect significant complications are key to maximizing the likelihood of prolonged graft and patient survival while avoiding significant complications following lung transplantation. Post-transplant outcomes will be optimized by a team approach to comprehensive management of the lung transplantation recipient combined with vigilant surveillance to detect complications in a timely fashion.

Endoscopic narrow-band imaging-quantitative assessment of airway vascularity after lung transplantation

In lung transplant recipients, the submucosal vascular plexus of the airway wall potentially represents one of the key structures of graft injury. Narrow band imaging is a novel endoscope technique that allows visual enhancement of the mucosa vasculature. It was our aim to investigate the ability of narrow-band imaging in combination with computerized image analysis to quantitatively assess airway vascularity in lung transplant recipients. In consecutive lung transplant recipients, in addition to the routine procedures, optical analysis of the main carina (autologous tissue) and the upper lobe carina (allogeneic tissue) were performed. From every site, three representative pictures were chosen. A total of 63 bronchoscopies were analyzed. The intraclass correlation coefficient (measure for test-retest reliability) of the three measurements were 0.69 and 0.74 for the main carina and the upper lobe carina, respectively. A mixed linear regression revealed increased vascularity in autologous tissue of patients with cystic fibrosis (p=0.06) and decreased vascularity in allogeneic tissue with time after transplantation (p=0.09). Endoscopic narrow-band imaging (NBI) in combination with computerized image analysis allows consistent assessment of airway vascularity in vivo. In lung transplant recipients, there might be differences in airway vascularity in both autologous and allogeneic large airways.

Primary graft dysfunction and long-term pulmonary function after lung transplantation

BACKGROUND

Severe primary graft dysfunction (PGD) is associated with poor early outcomes after lung transplantation (LTx). Less is known about lingering effects of severe PGD on pulmonary function. The study's aim was to determine whether development of severe primary graft dysfunction in the perioperative period was associated with reduced long term rates of survival or with diminished long term pulmonary function.

METHODS

A retrospective review was performed on LTx recipients who received their transplant during the period from 1992 through 2005. PGD severity over the first 48 hours post-transplant was graded using International Society for Heart Lung Transplantation criteria. Pulmonary function was evaluated yearly, and bronchiolitis obliterans syndrome (BOS) was determined from measurements of forced expiratory volume in 1 second (FEV(1)).

RESULTS

A total of 374 patients survived at least 90 days post-transplant. Overall survival rates were worse in patients with Grade 3 PGD: 51% at 5 years and 11% at 10 years for patients with Grade 3 PGD; 64% at 5 years and 35% at 10 years for those with Grade 2 PGD; and 66% at 5 years and 38% at 10 years for Grade 0 to 1 PGD (p = 0.001). BOS-free survival rate for patients with Grade 3 PGD was lower compared to those with Grade 0 to 2 for bilateral lung recipients, but not for single-lung recipients. Bilateral lung recipients who developed Grade 3 PGD had a significantly worse mean FEV(1) than those who did not. For single-lung recipients, PGD grade did not correlate with post-transplant pulmonary function.

CONCLUSIONS

Development of Grade 3 PGD in the early post-operative period negatively affects long-term survival, BOS-free survival and pulmonary function of bilateral lung transplant recipients who survive the peri-operative period.

Mucoviscidose : du bon usage des explorations fonctionnelles respiratoires

INTRODUCTION

Neonatal screening for cystic fibrosis (CF) leads to early dedicated specialist care for all patients.

BACKGROUND

Pulmonary function tests (PFT) are mandatory for routine monitoring of CF patients. The aim of this article is to review the current guidelines for PFTs in CF, particularly the type of test, the age and the clinical status of the patient.

VIEWPOINT

The regular use of spirometry is generally accepted. Many other tests are used but their clinical value in the routine follow-up of CF patients remains to be established.

CONCLUSION

Further efforts should be made to evaluate the value of PFTs in CF, particularly in very young children.

Disparities in solid organ transplantation for ethnic minorities: facts and solutions

The Diversity and Minority Affairs Committee of the American Society of Transplantation (AST) convened a symposium to examine organ transplantation in underserved and minority populations. The goals of the meeting included 'benchmarking' of solid organ transplantation among minority populations, review of the epidemiology of end-organ damage, exploration of barriers to transplantation services and development of approaches to eliminate disparities. Participants noted that minority populations were more likely to be adversely affected by limited preventive medical care, lack of counseling regarding transplant options, and delays in transplant referrals for organ transplantation. These features largely reflect economic disadvantage as well as the reduced presence of minority professionals with training in transplant-related specialties. Participants in the conference noted that recent changes in organ allocation policies had improved access to minority individuals once listed for renal transplantation. Similar advances will be needed for other organs to address inequities in pretransplant care and underrepresentation of minorities among transplant professionals. The biologic basis of differences in transplant outcomes for minority recipients has not been adequately studied. Research funds must be targeted to address biologic mechanisms underlying disparate transplant outcomes including the impacts of environment, education, poverty and lifestyle choices.

Sequential gene expression profiling in lung transplant recipients with chronic rejection

STUDY OBJECTIVES

Chronic allograft rejection is the leading cause of morbidity and mortality for long-term survivors of lung transplantation. Previous studies have implicated only isolated genes in the development of chronic rejection and have not examined multiple pathways in an individual concurrently. Using microarray technology, we identified and compared gene expression profiling in lung transplant recipients with and without chronic rejection, and follow sequential expression of genes differentially expressed between the two groups.

DESIGN

Prospective, cohort study.

SETTING

Single lung transplant center.

PATIENTS OR PARTICIPANTS

Eleven transplant recipients with chronic rejection were matched with 9 control transplant recipients.

INTERVENTIONS

All recipients underwent surveillance bronchoscopies at predetermined times to rule out infection and/or acute rejection. Gene expression profiling was obtained from hybridizing BAL fluid cell RNA to a 96-gene microarray.

MEASUREMENTS AND RESULTS

Fifteen genes were found to be significantly differentially expressed between the two patient groups, and they are involved in inflammatory, fibrotic, and apoptotic pathways. Temporal expression of the significant genes demonstrated a change in their levels at the onset of chronic rejection, with normalization to prerejection levels as rejection continued.

CONCLUSIONS

We conclude that microarray technology is valuable in studying the mechanism of chronic lung rejection, and the expression of genes in multiple pathways is elevated in patients with chronic lung rejection.

Lung Transplantation: Current Status and Challenges

The lung is an anatomically complex vital organ whose normal physiology depends on actively regulated ventilation and perfusion, and maintenance of a delicate blood-air barrier over a huge surface area in direct contact with a potentially hostile environment. Despite significant progress over the past 25 years, both short- and long-term outcomes remain significantly inferior for lung recipients relative to other "solid" organs. This review summarizes the current status of lung transplantation so as to frame the principle challenges currently facing end-stage lung-failure patients and the practitioners who care for them.

Everolimus in Pulmonary Transplantation: Pharmacokinetics and Exposure–Response Relationships

BACKGROUND

In this study we evaluated exposure, safety and efficacy data from an international trial of everolimus. We sought to identify a tolerated and efficacious range for blood levels of this agent in maintenance lung transplant recipients.

METHODS

In a randomized, double-blind, multicenter trial, 213 maintenance lung transplant recipients received either everolimus 1.5 mg twice daily (n = 101) or azathioprine 1 to 3 mg/kg/day (n = 112) with cyclosporine and corticosteroids. At 15 visits over the first 2 years of the trial, we obtained 826 everolimus trough (C0) blood samples. We used median-effect analysis to assess relationships between everolimus C0 vs efficacy and safety responses.

RESULTS

Everolimus administration began at 1.5 mg twice daily and was progressively lowered over the first 2 months to an average of 1.2 +/- 0.4 mg twice daily, which was maintained thereafter. This dose yielded median C0 levels of 6.6 ng/ml (10th to 90th percentiles: 2.8 to 11.8 ng/ml). Over this range of everolimus C0, freedom from a decline in pulmonary function with bronchiolitis obliterans syndrome and freedom from biopsy-proven acute rejection were both > or = 88%. The incidence of increased cholesterol (> 6.5 mmol/liter), increased triglycerides (> 2.9 mmol/liter) and transiently decreased platelet count (< 100 x 10(9)/liter) rose significantly with increasing C0. Infections and drug-related adverse events were not significantly related to exposure.

CONCLUSIONS

A tolerated and efficacious concentration range for everolimus in maintenance lung transplantation appears to be 3 to 12 ng/ml when used in conjunction with cyclosporine and corticosteroids. This range should be prospectively assessed with possible refinement as more clinical experience is gained.