Course of FEV(1) after onset of bronchiolitis obliterans syndrome in lung transplant recipients

Effective Extracorporeal Photopheresis of Patients with Transplantation Induced Acute Intestinal GvHD and Bronchiolitis Obliterans Syndrome

Background: Patients with steroid-refractory intestinal acute graft-versus-host disease (aGvHD) and bronchiolitis obliterans syndrome (BOS) represent a population with a high need for alternative and effective treatment options. Methods: We report real-life data from 18 patients treated with extracorporeal photopheresis (ECP). This cohort consisted of nine patients with steroid-refractory intestinal aGvHD and nine patients with BOS. Results: We document partial or complete clinical response and reduction of symptoms in half of the patients with intestinal acute GvHD and patients with BOS treated ECP. Responding patients tended to stay on treatment longer. In patients with BOS, stabilization of lung function and forced expiratory volume was observed, whereas, less abdominal pain, less diarrhea, and a reduction of systemic corticosteroids were seen in patients with intestinal acute GvHD. Conclusions: ECP might not only abrogate symptoms but also reduce mortality caused by complications from high-dose steroid treatment. Taken together, ECP offers a serious treatment avenue for patients with steroid-refractory intestinal acute GvHD and BOS.

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.

A randomized controlled trial of liposomal cyclosporine A for inhalation in the prevention of bronchiolitis obliterans syndrome following lung transplantation

Long-term survival after lung transplantation is limited by chronic allograft dysfunction. The aim of this study was to investigate the effect of locally augmented immunosuppression with liposomal cyclosporine A for inhalation (L-CsA-i) for the prevention of bronchiolitis obliterans syndrome (BOS). In a randomized, double-blind, placebo-controlled, multi-center Phase 3 study, 180 LT recipients in BOS grade 0 were planned to receive L-CsA-i or placebo in addition to triple-drug immunosuppression. L-CsA-i was administered twice daily via an Investigational eFlow nebulizer to recipients of single (SLT) and bilateral lung transplants (BLT) within 6-32 weeks posttransplant, and continued for 2 years. The primary endpoint was BOS-free survival. 130 patients were enrolled before the study was prematurely terminated for business reasons. Despite a 2-year actuarial difference in BOS-free survival of 14.1% in favor of L-CsA-i in the overall study population, the primary endpoint was not met (p = .243). The pre-defined per protocol analysis of SLT recipients (n = 24) resulted in a treatment difference of 58.2% (p = .053). No difference was observed in the BLT (n = 48) subpopulation (p = .973). L-CsA-i inhalation was well tolerated. Although this study failed to meet its primary endpoint, the results warrant additional investigation of L-CsA-i in lung transplant recipients.

Disease progression in patients with the restrictive and mixed phenotype of Chronic Lung Allograft dysfunction-A retrospective analysis in five European centers to assess the feasibility of a therapeutic trial

BACKGROUND

Chronic Lung Allograft Dysfunction (CLAD) is a major obstacle for long term survival after lung transplantation (LTx). Besides Bronchiolitis Obliterans Syndrome, two other phenotypes of CLAD, restrictive allograft syndrome (RAS) and mixed phenotype, have been described. Trials to test in these conditions are desperately needed and analyzing natural outcome to plan such trials is essential.

METHODS

We performed a retrospective analysis of functional outcome in bilateral LTx recipients with RAS and mixed phenotype, transplanted between 2009 and 2018 in five large European centers with follow- up spirometry up to 12 months after diagnosis. Based on these data, sample size and power calculations for randomized therapeutic trial was estimated using two imputation methods for missing values.

RESULTS

Seventy patients were included (39 RAS and 31 mixed phenotype), median 3.1 years after LTx when CLAD was diagnosed. Eight, 13 and 25 patients died within 6, 9 and 12 months after diagnosis and a two patients underwent re-transplantation within 12 months leading to a graft survival of 89, 79 and 61% six, nine and 12 months after diagnosis, respectively. Observed FEV1 decline was 451 ml at 6 months and stabilized at 9 and 12 months, while FVC showed continuous decline. Using two methods of imputation, a progressive further decline after 6 months for FEV1 was noted.

CONCLUSION

The poor outcome of these two specific CLAD phenotypes suggests the urgent need for future therapeutic randomized trials. The number of missing values in a potential trial seems to be high and most frequently attributed to death. Survival may be used as an endpoint in clinical trials in these distinct phenotypes and imputation techniques are relevant if graft function is used as a surrogate of disease progression in future trials.

The association of lung function changes with outcomes in children with bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a life-threatening respiratory complication of allogeneic hematopoietic stem cell transplantation (HSCT). Although pulmonary function testing is crucial for monitoring BOS, little information exists on the association of these test results with outcomes in children with BOS.

OBJECTIVES

The purpose of this study was to determine the correlation between changes in lung function after BOS diagnosis and long-term outcomes.

METHODS

A total of 428 children underwent allogeneic HSCT from January 2006 to December 2017 at Asan Medical Center. Twenty-three (5.4%) were diagnosed with BOS after allogeneic HSCT, and their clinical data were reviewed. Twenty-one subjects underwent regular pulmonary function testing for 24 months after BOS diagnosis.

RESULTS

Among the 21 children with BOS, 8 died, 5 underwent lung transplantation (TPL), and 15 required oxygen (O₂ ) therapy. The FEV₁ % predicted (pred), FVC% pred, and FEF_25%-75% pred were 37.8 ± 12.7% (mean ± SD), 62.2 ± 16.2%, and 16.4 ± 9.6%, respectively, at the time of BOS diagnosis. Changes in the FEV₁ % pred were greater in the death and lung TPL groups (-24.8 ± 22.3%) than in the survival without lung TPL group (5.7 ± 21.8%) and greater in the O₂ therapy (-19.4 ± 23.4%) group than in the group without O₂ therapy (14.2 ± 20.0%) during the first 3 months after BOS diagnosis.

CONCLUSION

The change in FEV₁ during the first 3 months after BOS diagnosis correlated with outcomes including survival, lung TPL, and O₂ therapy. These results suggest that more active intervention in the first 3 months after BOS diagnosis may be needed to improve prognosis.

Chronic Lung Allograft Dysfunction: Evolving Concepts and Therapies

The primary factor that limits long-term survival after lung transplantation is chronic lung allograft dysfunction (CLAD). CLAD also impairs quality of life and increases the costs of medical care. Our understanding of CLAD continues to evolve. Consensus definitions of CLAD and the major CLAD phenotypes were recently updated and clarified, but it remains to be seen whether the current definitions will lead to advances in management or impact care. Understanding the potential differences in pathogenesis for each CLAD phenotype may lead to novel therapeutic strategies, including precision medicine. Recognition of CLAD risk factors may lead to earlier interventions to mitigate risk, or to avoid risk factors all together, to prevent the development of CLAD. Unfortunately, currently available therapies for CLAD are usually not effective. However, novel therapeutics aimed at both prevention and treatment are currently under investigation. We provide an overview of the updates to CLAD-related terminology, clinical phenotypes and their diagnosis, natural history, pathogenesis, and potential strategies to treat and prevent CLAD.

Donor-derived cell-free DNA accurately detects acute rejection in lung transplant patients, a multicenter cohort study

BACKGROUND

Acute rejection, which includes antibody-mediated rejection and acute cellular rejection, is a risk factor for lung allograft loss. Lung transplant patients often undergo surveillance transbronchial biopsies to detect and treat acute rejection before irreversible chronic rejection develops. Limitations of this approach include its invasiveness and high interobserver variability. We tested the performance of percent donor-derived cell-free DNA (%ddcfDNA), a non-invasive blood test, to detect acute rejection.

METHODS

This multicenter cohort study monitored 148 lung transplant subjects over a median of 19.6 months. We collected serial plasma samples contemporaneously with TBBx to measure %ddcfDNA. Clinical data was collected to adjudicate for acute rejection. The primary analysis consisted of computing the area-under-the-receiver-operating-characteristic-curve of %ddcfDNA to detect acute rejection. Secondary analysis determined %ddcfDNA rule-out thresholds for acute rejection.

RESULTS

ddcfDNA levels were high after transplant surgery and decayed logarithmically. With acute rejection, ddcfDNA levels rose six-fold higher than controls. ddcfDNA levels also correlated with severity of lung function decline and histological grading of rejection. %ddcfDNA area-under-the-receiver-operating-characteristic-curve for acute rejection, AMR, and ACR were 0.89, 0.93, and 0.83, respectively. ddcfDNA levels of <0.5% and <1.0% showed a negative predictive value of 96% and 90% for acute rejection, respectively. Histopathology detected one-third of episodes with ddcfDNA levels ≥1.0%, even though >90% of these events were coincident to clinical complications missed by histopathology.

CONCLUSIONS

This study demonstrates that %ddcfDNA reliably detects acute rejection and other clinical complications potentially missed by histopathology, lending support to its use as a non-invasive marker of allograft injury.

Chronic Lung Allograft Dysfunction: Review of CT and Pathologic Findings

Chronic lung allograft dysfunction (CLAD) is the most common cause of mortality in lung transplant recipients after the 1st year of transplantation. CLAD has traditionally been classified into two distinct obstructive and restrictive forms: bronchiolitis obliterans syndrome and restrictive allograft syndrome. However, CLAD may manifest with a spectrum of imaging and pathologic findings and a combination of obstructive and restrictive physiologic abnormalities. Although the initial CT manifestations of CLAD may be nonspecific, the progression of findings at follow-up should signal the possibility of CLAD and may be present on imaging studies prior to the development of functional abnormalities of the lung allograft. This review encompasses the evolution of CT findings in CLAD, with emphasis on the underlying pathogenesis and pathologic condition, to enhance understanding of imaging findings. The purpose of this article is to familiarize the radiologist with the initial and follow-up CT findings of the obstructive, restrictive, and mixed forms of CLAD, for which early diagnosis and treatment may result in improved survival. Supplemental material is available for this article. © RSNA, 2021.

Self-reactive antibodies associated with bronchiolitis obliterans syndrome subtype of chronic lung allograft dysfunction

BACKGROUND

Chronic Lung Allograft Dysfunction (CLAD) remains the major limitation in long term survival after lung transplantation. Our objective is to evaluate for the presence of autoantibodies to self-antigens, which is a pathway along with complex interplay with immune as well as non-immune mechanisms that leads to a fibroproliferative process resulting in CLAD.

METHODS

Serum profiles of IgG autoantibodies were evaluated using customized proteomic microarray with 124 antigens. Output from microarray analyzed as antibody scores is correlated with bronchiolitis obliterans (BOS) subtype of CLAD using Mann-Whitney U test or Fisher exact test. Autoantibodies were evaluated for their predictive value for progressive BOS using a Cox proportional hazard model. BOS free survival and overall survival was analyzed using Kaplan-Meier survival analysis.

RESULTS

Forty- two patients included in the study are grouped into "stable BOS" and "progressive BOS" for comparisons. Pulmonary fibrosis is the major indication for lung transplantation in our cohort. Progressive BOS group had significantly worse survival (p < 0.005). Sixteen IgG autoantibodies are significantly elevated at baseline in progressive BOS group. Six among them correlated with worse BOS free survival (p < 0.05). In addition, these six IgG autoantibodies remain elevated at three months and one year after lung transplantation.

CONCLUSION

Pre-existing IgG autoantibodies correlate with progressive BOS and survival in a single center, small cohort of lung transplant recipients. Further validation with larger sample size, external cohort and confirmation with additional tissue, bronchoalveolar lavage samples are necessary to confirm the preliminary findings in our study.

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.

A randomised single-centre trial of inhaled liposomal cyclosporine for bronchiolitis obliterans syndrome post-lung transplantation

Introduction

No proven treatments exist for bronchiolitis obliterans syndrome (BOS) following lung transplantation. Inhaled liposomal cyclosporine (L-CsA) may prevent BOS progression.

Methods

A 48-week phase IIb randomised clinical trial was conducted in 21 lung transplant patients with BOS assigned to either L-CsA with standard-of-care (SOC) oral immunosuppression (L-CsA group) or SOC (SOC-alone group). Efficacy end-points were BOS progression-free survival (defined as absence of ≥20% decline in forced expiratory volume in 1 s (FEV₁) from randomisation, re-transplantation or death) and BOS grade change.

Results

BOS progression-free survival was 82% for L-CsA versus 50% for SOC-alone (p=0.1) and BOS grade worsened in 18% for L-CsA versus 60% for SOC-alone (p=0.05). Mean changes in ΔFEV₁ and forced vital capacity, respectively, stabilised with L-CsA: +0.005 (95% CI −0.004– +0.013) and −0.005 (95% CI −0.015– +0.006) L·month⁻¹, but worsened with SOC-alone: −0.023 (95% CI −0.033– −0.013) and −0.026 (95% CI −0.039– −0.014) L·month⁻¹ (p<0.0001 and p=0.009). Median survival (4.1 versus 2.9 years; p=0.03) and infection rate (45% versus 60%; p=0.7) improved with L-CsA versus SOC-alone; creatinine and tacrolimus levels were similar.

Conclusions

L-CsA was well tolerated and stabilised lung function in lung transplant recipients affected by BOS without systemic toxicity, providing a basis for a global phase III trial using L-CsA.

Liposomal aerosol cyclosporine (L-CsA) was well tolerated and stabilised lung function in lung transplant recipients affected by BOS. The data provide evidence for an ongoing global phase III trial using L-CsA for BOS.http://bit.ly/2HB8w5j

Long-term effect of azithromycin in bronchiolitis obliterans syndrome

Introduction

Azithromycin stabilises and improves lung function forced expiratory volume in one second (FEV₁) in lung transplantation patients with bronchiolitis obliterans syndrome (BOS). A post hoc analysis was performed to assess the long-term effect of azithromycin on FEV₁, BOS progression and survival .

Methods

Eligible patients recruited for the initial randomised placebo-controlled trial received open-label azithromycin after 3 months and were followed up until 6 years after inclusion (n=45) to assess FEV₁, BOS free progression and overall survival.

Results

FEV₁ in the placebo group improved after open-label azithromycin and was comparable with the treatment group by 6 months. FEV₁ decreased after 1 and 5 years and was not different between groups. Patients (n=18) with rapid progression of BOS underwent total lymphoid irradiation (TLI). Progression-free survival (log-rank test p=0.40) and overall survival (log-rank test p=0.28) were comparable. Survival of patients with early BOS was similar to late-onset BOS (log-rank test p=0.74).

Discussion

Long-term treatment with azithromycin slows down the progression of BOS, although the effect of TLI may affect the observed attenuation of FEV₁ decline. BOS progression and long-term survival were not affected by randomisation to the placebo group, given the early cross-over to azithromycin and possibly due to TLI in case of further progression. Performing randomised placebo-controlled trials in lung transplantation patients with BOS with a blinded trial duration is feasible, effective and safe.

Rabbit antithymocyte globulin for the treatment of chronic lung allograft dysfunction

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is the leading cause of death beyond the first year after lung transplantation. Several treatments have been used to prevent the progression or reverse the effects of CLAD. Cytolytic therapy with rabbit antithymocyte globulin (rATG) has previously shown to be a potential option. However, the effect on patients with restrictive allograft syndrome (RAS) versus bronchiolitis obliterans syndrome (BOS) and the effect of cumulative dosing are unknown.

METHODS

The charts of lung transplant patients treated with rATG at Barnes-Jewish Hospital from 2009 to 2016 were retrospectively reviewed. The primary outcome was response to rATG; patients were deemed responders if their FEV₁ improved in the 6 months after rATG treatment. Safety endpoints included incidence of serum sickness, cytokine release syndrome, malignancy, and infectious complications.

RESULTS

108 patients were included in this study; 43 (40%) patients were responders who experienced an increase in FEV₁ after rATG therapy. No predictors of response to rATG therapy were identified. Serum sickness occurred in 22% of patients, 15% experienced cytokine release syndrome, and 19% developed an infection after therapy.

CONCLUSION

40% of patients with CLAD have an improvement in lung function after treatment with rATG although the improvement was typically minimal.

MRI-derived regional flow-volume loop parameters detect early-stage chronic lung allograft dysfunction

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is a major cause for the low long-term survival rates after lung transplantation (LTx). Early detection of CLAD may enable providing medical treatment before a nonreversible graft dysfunction has occurred. MRI is advantageous to pulmonary function testing (PFT) in the ability to assess regional function changes, and thus have the potential in detecting very early stages of CLAD before changes in global forced expiratory volume during the first second (FEV1%) occur.

PURPOSE

To examine whether early stages of CLAD (diagnosed based on PFT values) could also be detected using MRI-derived parameters of regional flow-volume dynamics.

STUDY TYPE

Retrospective.

POPULATION

62 lung transplantation recipients were included in the study, 29 of which had been diagnosed with CLAD at various stages.

FIELD STRENGTH/SEQUENCE

MRI datasets were acquired with a 1.5T Siemens scanner using a spoiled gradient echo sequence.

ASSESSMENT

MRI datasets were retrospectively preprocessed and analyzed by a blinded radiologist according to the phase resolved functional lung MRI (PREFUL-MRI) approach, resulting in fractional ventilation (FV) maps and regional flow-volume loops (rFVL). FV- and rFVL-based parameters of regional lung ventilation were estimated.

STATISTICAL TESTS

Differences between groups were compared by Mann-Whitney U-test with a Bonferroni correction for multiple comparisons (n = 2).

RESULTS

rFVL-CC-based parameters discriminated significantly between the presence or absence of CLAD (P < 0.003).

DATA CONCLUSION

Using the contrast media-free PREFUL-MRI technique, parameters of ventilation dynamics and its regional heterogeneity were shown to be sensitive for the detection of early CLAD stages.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 3 J. Magn. Reson. Imaging 2019;50:1873-1882.

Diagnosis, Pathophysiology and Experimental Models of Chronic Lung Allograft Rejection

Chronic rejection is the Achilles heel of modern lung transplantation, characterized by a slow, progressive decline in allograft function. Clinically, this manifests as obstructive disease, restrictive disease, or a mixture of the 2 depending on the underlying pathology. The 2 major phenotypes of chronic rejection include bronchiolitis obliterans syndrome and restrictive allograft syndrome. The last decade of research has revealed that each of these phenotypes has a unique underlying pathophysiology which may require a distinct treatment regimen for optimal control. Insights into the intricate alloimmune pathways contributing to chronic rejection have been gained from both large and small animal models, suggesting directions for future research. In this review, we explore the pathological hallmarks of chronic rejection, recent insights gained from both clinical and basic science research, and the current state of animal models of chronic lung rejection.

EXERCISE CAPACITY IN CHILDREN AND ADOLESCENTS WITH POST-INFECTIOUS BRONCHIOLITIS OBLITERANS: A SYSTEMATIC REVIEW

Objective:

To evaluate exercise capacity in children and adolescents with post-infectious bronchiolitis obliterans.

Data source:

This is a systematic review based on data from PubMed, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Scientific Electronic Library Online (SciELO), and Physiotherapy Evidence Database (PEDro). We used the following search strategy: “Exercise capacity OR Exercise Test OR Physical fitness OR Functional capacity OR Six-minute walk test OR Shuttle walk test OR Cardiopulmonary exercise test AND Bronchiolitis obliterans.” We selected studies that evaluated exercise capacity through maximal/submaximal testing in children and adolescents with post-infectious bronchiolitis obliterans, and no other associated disease. We searched articles in English, Portuguese, and Spanish, without restrictions regarding the period of publication. The methodological quality was assessed by the Agency for Healthcare Research and Quality (AHRQ) protocol.

Data synthesis:

Out of the 81 articles found, only 4 were included in this review. The studies totaled 135 participants (121 with post-infectious bronchiolitis obliterans and 14 healthy), with sample sizes between 14 and 58 subjects. All patients underwent spirometry to evaluate pulmonary function, indicating an obstructive ventilatory pattern. Among them, 3/4 had their physical performance assessed by the six-minute walk test and 2/4 by the cardiopulmonary exercise testing. These test results were compared to those of a control group (1/4) and presented as percentage of predicted and/or in meters (3/4). Lastly, 3/4 of the studies showed reduced exercise capacity in this population. The studies included were classified as having high methodological quality.

Conclusions:

Findings of the study demonstrate that children and adolescents with post-infectious bronchiolitis obliterans have reduced exercise capacity.

Extracorporeal Photopheresis for Bronchiolitis Obliterans Syndrome After Lung Transplantation

BACKGROUND

Lung transplantation is a therapeutic option for select patients with end-stage lung disease. However, successful lung transplantation is hampered by chronic lung allograft dysfunction, in particular bronchiolitis obliterans syndrome (BOS). Although there is no approved or standard treatment for BOS, which may have several distinct phenotypes, extracorporeal photopheresis (ECP) has shown promising results in patients who develop BOS refractory to azithromycin treatment.

METHODS

We reviewed all relevant clinical data indexed on PubMed from 1987 to 2017 to evaluate the role of ECP in patients with BOS.

RESULTS

Seven small studies investigated the immunomodulatory effects of ECP in patients after solid organ transplant, and 12 studies reported clinical data specific to ECP therapy for BOS. Studies indicate that ECP triggers an apoptotic cellular cascade that exerts various immunomodulatory effects mediated via increases in anti-inflammatory cytokines, a decrease in proinflammatory cytokines, and an increase in tolerogenic regulatory T cells. Clinical evidence derived from relatively small single-center studies suggests that ECP therapy is associated with improvement or stabilization in lung function and sustainable, statistically significant, decreases in the rate of lung function decline in patients with BOS. Additionally, when adverse event data were reported, ECP was generally well tolerated. None of the comparative studies were randomized.

CONCLUSIONS

Immunomodulation mediated via ECP is a rational therapeutic option that may improve clinical outcomes in patients with BOS, particularly in the context of in-depth patient phenotyping as part of a stratified approach to treatment; good quality randomized controlled trials are needed to confirm observational findings.

Donor-derived cell-free DNA predicts allograft failure and mortality after lung transplantation

Background

Allograft failure is common in lung-transplant recipients and leads to poor outcomes including early death. No reliable clinical tools exist to identify patients at high risk for allograft failure. This study tested the use of donor-derived cell-free DNA (%ddcfDNA) as a sensitive marker of early graft injury to predict impending allograft failure.

Methods

This multicenter, prospective cohort study enrolled 106 subjects who underwent lung transplantation and monitored them after transplantation for the development of allograft failure (defined as severe chronic lung allograft dysfunction [CLAD], retransplantation, and/or death from respiratory failure). Plasma samples were collected serially in the first three months following transplantation and assayed for %ddcfDNA by shotgun sequencing. We computed the average levels of ddcfDNA over three months for each patient (avddDNA) and determined its relationship to allograft failure using Cox-regression analysis.

Findings

avddDNA was highly variable among subjects: median values were 3·6%, 1·6% and 0·7% for the upper, middle, and low tertiles, respectively (range 0·1%–9·9%). Compared to subjects in the low and middle tertiles, those with avddDNA in the upper tertile had a 6·6-fold higher risk of developing allograft failure (95% confidence interval 1·6–19·9, p = 0·007), lower peak FEV1 values, and more frequent %ddcfDNA elevations that were not clinically detectable.

Interpretation

Lung transplant patients with early unresolving allograft injury measured via %ddcfDNA are at risk of subsequent allograft injury, which is often clinically silent, and progresses to allograft failure.

Fund

National Institutes of Health.

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

BACKGROUND

Chronic lung allograft dysfunction (CLAD), including the phenotypes of bronchiolitis obliterans syndrome (BOS) and restrictive CLAD (R-CLAD), represents the leading cause of late death after lung transplantation. Little is known, however, regarding the natural history or prognostic significance of pulmonary function changes after the onset of these conditions. We examined changes in forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) over the first 18 months after CLAD. We also sought to determine whether lung function changes occurring early after CLAD impact longer term outcomes.

METHODS

We performed a retrospective analysis of 216 bilateral lung recipients with CLAD, which included those with R-CLAD (n = 65) or BOS (n = 151). The course of FEV₁ and FVC after CLAD was described. Cox proportional hazards models were used to evaluate the impact of a ≥10% decline in FEV₁ or FVC within the first 6 months of CLAD on graft loss after that time.

RESULTS

Lung recipients with CLAD, whether BOS or R-CLAD, had the largest decreases in FEV₁ and FVC within the first 6 months after onset. Moreover, a decline in FEV₁ or FVC of ≥10% within the first 6 months after CLAD was associated with a significantly increased hazard for graft loss after that time (hazard ratio [HR] = 3.17, 95% confidence interval [CI] 1.56 to 6.42, p = 0.001, and HR = 2.80, 95% CI 1.66 to 4.70, p ≤ 0.001, respectively), an effect observed in both BOS and R-CLAD patients.

CONCLUSIONS

Early physiologic changes after CLAD were independently associated with graft loss. This suggests lung function changes after CLAD, specifically a ≥10% decline in FEV₁ or FVC, could be a surrogate measure of graft survival.

Lung Function Trajectory in Bronchiolitis Obliterans Syndrome after Allogeneic Hematopoietic Cell Transplant

RATIONALE

The natural history of lung function in patients with bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic cell transplant is poorly characterized. Understanding the trajectory of lung function is necessary for prompt clinical recognition and treatment and also for the rational design of prospective studies.

OBJECTIVES

To describe the longitudinal trajectory of lung function parameters, including FEV₁, in patients with BOS after hematopoietic cell transplant.

METHODS

Subjects with BOS defined by National Institutes of Health consensus guidelines criteria from a recent multicenter prospective trial of combination treatment with fluticasone, azithromycin and montelukast and a retrospective cohort from Fred Hutchinson Cancer Research Center were included. Longitudinal change in FEV₁ for each patient was calculated on the basis of available pulmonary function tests in three periods: pre-BOS, from BOS diagnosis to 6 months, and 6-18 months after diagnosis. The effect of treatment on FEV₁ trajectory was analyzed by univariate and multivariate linear regression. The Kaplan-Meier method was used to estimate survival.

MEASUREMENTS AND MAIN RESULTS

The FEV₁ percent predicted value at diagnosis was 46% (interquartile range, 35-57%) for trial participants and 53% (interquartile range, 41-64%) for the retrospective cohort. There was a concomitant mild reduction in FVC, as well as a marked reduction in forced expiratory flow, midexpiratory phase, at diagnosis. While there was individual heterogeneity, the overall FEV₁ trajectory was characterized by a marked decline within 6 months prior to BOS diagnosis, followed by stability of FEV₁ early after diagnosis and a slow rate of decline beyond 6 months. The effect of the trial medications on FEV₁ trajectory after BOS diagnosis was a mean rate of change of 0.92% predicted per month (95% confidence interval, -0.53 to 2.37) compared with the retrospective cohort, but this was not statistically significant. Two-year overall survival rates were 76% and 72% for the study participants and the retrospective cohort patients, respectively. Earlier time to diagnosis after hematopoietic cell transplant and severity of FVC at diagnosis were significantly associated with reduced survival.

CONCLUSIONS

The FEV₁ trajectory in patients with BOS after hematopoietic cell transplant in a contemporary era of management follows a predominant pattern of rapid FEV₁ decline in the 6 months prior to diagnosis, followed by FEV₁ stabilization after diagnosis.

Update in Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation to posttransplant survival. This review highlights the evolving definition of CLAD, risk factors, treatment, and expected outcomes after the development of CLAD.

Parametric Response Mapping as an Imaging Biomarker in Lung Transplant Recipients

RATIONALE

The predominant cause of chronic lung allograft failure is small airway obstruction arising from bronchiolitis obliterans. However, clinical methodologies for evaluating presence and degree of small airway disease are lacking.

OBJECTIVES

To determine if parametric response mapping (PRM), a novel computed tomography voxel-wise methodology, can offer insight into chronic allograft failure phenotypes and provide prognostic information following spirometric decline.

METHODS

PRM-based computed tomography metrics quantifying functional small airways disease (PRM^fSAD) and parenchymal disease (PRM^PD) were compared between bilateral lung transplant recipients with irreversible spirometric decline and control subjects matched by time post-transplant (n = 22). PRM^fSAD at spirometric decline was evaluated as a prognostic marker for mortality in a cohort study via multivariable restricted mean models (n = 52).

MEASUREMENTS AND MAIN RESULTS

Patients presenting with an isolated decline in FEV₁ (FEV₁ First) had significantly higher PRM^fSAD than control subjects (28% vs. 15%; P = 0.005), whereas patients with concurrent decline in FEV₁ and FVC had significantly higher PRM^PD than control subjects (39% vs. 20%; P = 0.02). Over 8.3 years of follow-up, FEV₁ First patients with PRM^fSAD greater than or equal to 30% at spirometric decline lived on average 2.6 years less than those with PRM^fSAD less than 30% (P = 0.004). In this group, PRM^fSAD greater than or equal to 30% was the strongest predictor of survival in a multivariable model including bronchiolitis obliterans syndrome grade and baseline FEV_1% predicted (P = 0.04).

CONCLUSIONS

PRM is a novel imaging tool for lung transplant recipients presenting with spirometric decline. Quantifying underlying small airway obstruction via PRM^fSAD helps further stratify the risk of death in patients with diverse spirometric decline patterns.

Development of a Multivariate Prediction Model for Early-Onset Bronchiolitis Obliterans Syndrome and Restrictive Allograft Syndrome in Lung Transplantation

BACKGROUND

Chronic lung allograft dysfunction and its main phenotypes, bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS), are major causes of mortality after lung transplantation (LT). RAS and early-onset BOS, developing within 3 years after LT, are associated with particularly inferior clinical outcomes. Prediction models for early-onset BOS and RAS have not been previously described.

METHODS

LT recipients of the French and Swiss transplant cohorts were eligible for inclusion in the SysCLAD cohort if they were alive with at least 2 years of follow-up but less than 3 years, or if they died or were retransplanted at any time less than 3 years. These patients were assessed for early-onset BOS, RAS, or stable allograft function by an adjudication committee. Baseline characteristics, data on surgery, immunosuppression, and year-1 follow-up were collected. Prediction models for BOS and RAS were developed using multivariate logistic regression and multivariate multinomial analysis.

RESULTS

Among patients fulfilling the eligibility criteria, we identified 149 stable, 51 BOS, and 30 RAS subjects. The best prediction model for early-onset BOS and RAS included the underlying diagnosis, induction treatment, immunosuppression, and year-1 class II donor-specific antibodies (DSAs). Within this model, class II DSAs were associated with BOS and RAS, whereas pre-LT diagnoses of interstitial lung disease and chronic obstructive pulmonary disease were associated with RAS.

CONCLUSION

Although these findings need further validation, results indicate that specific baseline and year-1 parameters may serve as predictors of BOS or RAS by 3 years post-LT. Their identification may allow intervention or guide risk stratification, aiming for an individualized patient management approach.

Early extracellular matrix changes are associated with later development of bronchiolitis obliterans syndrome after lung transplantation

Background

Chronic lung allograft dysfunction in the form of bronchiolitis obliterans syndrome (BOS) is the main cause of death beyond 1-year post-lung transplantation. The disease-initiating triggers as well as the molecular changes leading to fibrotic alterations in the transplanted lung are largely unknown. The aim of this study was to identify potential early changes in the extracellular matrix (ECM) in different compartments of the transplanted lung prior to the development of BOS.

Methods

Transbronchial biopsies from a cohort of 58 lung transplantation patients at the Copenhagen University hospital between 2005 and 2006, with or without development of BOS in a 5-year follow-up, were obtained 3 and 12 months after transplantation. Biopsies were assessed for total collagen, collagen type IV and biglycan in the alveolar and small airway compartments using Masson's Trichrome staining and immunohistochemistry.

Results

A time-specific and compartment-specific pattern of ECM changes was detected. Alveolar total collagen (p=0.0190) and small airway biglycan (p=0.0199) increased between 3 and 12 months after transplantation in patients developing BOS, while collagen type IV (p=0.0124) increased in patients without BOS. Patients with early-onset BOS mirrored this increase. Patients developing grade 3 BOS showed distinct ECM changes already at 3 months. Patients with BOS with treated acute rejections displayed reduced alveolar total collagen (p=0.0501) and small airway biglycan (p=0.0485) at 3 months.

Conclusions

Patients with future BOS displayed distinct ECM changes compared with patients without BOS. Our data indicate an involvement of alveolar and small airway compartments in post-transplantation changes in the development of BOS.

Comparison of extracorporeal photopheresis and alemtuzumab for the treatment of chronic lung allograft dysfunction

BACKGROUND

Survival after lung transplantation is limited by chronic lung allograft dysfunction (CLAD). Immunomodulatory therapies such as extracorporeal photopheresis (ECP) and alemtuzumab (AL) have been described for refractory CLAD, but comparative outcomes are not well defined.

METHODS

We retrospectively reviewed spirometric values and clinical outcomes after therapy with ECP, AL, or no treatment (NT) in patients with CLAD who underwent transplant between January 2005 and December 2014. We used inverse probability-weighted regression adjustment (IPWRA) to adjust for potential confounders affecting treatment choice.

RESULTS

Of 267 patients, 31 received immunomodulatory therapies for CLAD, and 78 received NT. The slope of forced expiratory volume in 1 second (FEV₁) decline significantly improved after treatment with AL and with ECP compared with pre-treatment FEV₁ slope; however, there was no significant change in slope of forced vital capacity (FVC). Comparison with NT was limited because of clinical differences in treatment groups. After IPWRA, we found no significant difference in mean difference of FEV₁ slope (ml/month) when comparing treatment with NT, suggesting stabilization of lung function in the treatment group. We found no difference between the 2 immunomodulatory therapies 1, 3, and 6 months post-treatment (-49.9 [95% CI -581.8, +482.0], p = 0.85; +27.7 [95% CI -167.6, +223.0], p = 0.78; -9.6 [95% CI -167.5, +148.2], p = 0.91). We found no difference in mean FVC slope or differences between ECP and AL in infection rates or survival after treatment.

CONCLUSIONS

Immunomodulatory therapy for CLAD with ECP or AL was associated with a significant change in FEV₁ slope post-treatment compared with pre-treatment slope, with minimal effect on FVC. There was no difference between the 2 therapies in their effect on pulmonary function.

Longitudinal Forced Vital Capacity Monitoring as a Prognostic Adjunct after Lung Transplantation

RATIONALE

After lung transplantation, spirometric values are routinely followed to assess graft function. FEV1 is used to characterize chronic allograft dysfunction, whereas the course of FVC change has been less acknowledged and rarely used.

OBJECTIVES

To better understand the temporal relationship and prognostic ability of FEV1 and FVC decline after lung transplantation.

METHODS

Serial FEV1 and FVC values were studied among 205 bilateral lung transplant recipients. Different decline patterns were characterized and evaluated for prognostic value via restricted mean modeling of mortality and times to other pertinent events.

MEASUREMENTS AND MAIN RESULTS

Baseline FEV1 was achieved earlier than baseline FVC (median, 296 vs. 378 d; P < 0.0001). Decline in FEV1 or FVC from their respective post-transplant baselines occurred in 85 patients (41%). Fifty-nine of 85 (69%) had an isolated FEV1 decline, with 80% later meeting the FVC decline criterion. This subsequent FVC decline was associated with worsening FEV1 and lower median survival. Twenty-five of 85 patients (29%) demonstrated concurrent FEV1 and FVC decline. Patients with concurrent decline had higher 1- and 5-year mortality rates (1-yr, 53% vs. 18%, P < 0.0001; 5-yr, 61% vs. 48%, P = 0.001). These patients were more likely to have rapid-onset of spirometry decline (P = 0.05) and lower FEV1% predicted (P = 0.04) at presentation.

CONCLUSIONS

FVC decline from its post-transplant baseline provides valuable prognostic information. Concurrent FEV1 and FVC decline identifies patients with fulminant, rapid deterioration and is the strongest clinical predictor of poor survival. Subsequent FVC decline in patients with an initial isolated FEV1 decline identifies disease progression and portends poor prognosis.

Chronic obstructive pulmonary disease

COPD is characterized by airflow limitation that is not fully reversible. The morphological basis for airflow obstruction results from a varying combination of obstructive changes in peripheral conducting airways and destructive changes in respiratory bronchioles, alveolar ducts, and alveoli. A reduction of vascularity within the alveolar septa has been reported in emphysema. Typical physiological changes reflect these structural abnormalities. Spirometry documents airflow obstruction when the FEV1/FVC ratio is reduced below the lower limit of normality, although in early disease stages FEV1 and airway conductance are not affected. Current guidelines recommend testing for bronchoreversibility at least once and the postbronchodilator FEV1/FVC be used for COPD diagnosis; the nature of bronchodilator response remains controversial, however. One major functional consequence of altered lung mechanics is lung hyperinflation. FRC may increase as a result of static or dynamic mechanisms, or both. The link between dynamic lung hyperinflation and expiratory flow limitation during tidal breathing has been demonstrated. Hyperinflation may increase the load on inspiratory muscles, with resulting length adaptation of diaphragm. Reduction of exercise tolerance is frequently noted, with compelling evidence that breathlessness and altered lung mechanics play a major role. Lung function measurements have been traditionally used as prognostic indices and to monitor disease progression; FEV1 has been most widely used. An increase in FVC is also considered as proof of bronchodilatation. Decades of work has provided insight into the histological, functional, and biological features of COPD. This has provided a clearer understanding of important pathobiological processes and has provided additional therapeutic options.

An international ISHLT/ATS/ERS clinical practice guideline: diagnosis and management of bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is a major complication of lung transplantation that is associated with poor survival. The International Society for Heart and Lung Transplantation, American Thoracic Society, and European Respiratory Society convened a committee of international experts to describe and/or provide recommendations for 1) the definition of BOS, 2) the risk factors for developing BOS, 3) the diagnosis of BOS, and 4) the management and prevention of BOS. A pragmatic evidence synthesis was performed to identify all unique citations related to BOS published from 1980 through to March, 2013. The expert committee discussed the available research evidence upon which the updated definition of BOS, identified risk factors and recommendations are based. The committee followed the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) approach to develop specific clinical recommendations. The term BOS should be used to describe a delayed allograft dysfunction with persistent decline in forced expiratory volume in 1 s that is not caused by other known and potentially reversible causes of post-transplant loss of lung function. The committee formulated specific recommendations about the use of systemic corticosteroids, cyclosporine, tacrolimus, azithromycin and about re-transplantation in patients with suspected and confirmed BOS. The diagnosis of BOS requires the careful exclusion of other post-transplant complications that can cause delayed lung allograft dysfunction, and several risk factors have been identified that have a significant association with the onset of BOS. Currently available therapies have not been proven to result in significant benefit in the prevention or treatment of BOS. Adequately designed and executed randomised controlled trials that properly measure and report all patient-important outcomes are needed to identify optimal therapies for established BOS and effective strategies for its prevention.

Pediatric lung transplantation: promise being realized

PURPOSE OF REVIEW

Lung transplantation for infants and children is an accepted but rarely exercised option for the treatment of end-stage lung disease, with outcomes equivalent to those for adults. However, widespread misconceptions regarding pediatric outcomes often confound timely and appropriate referral to specialty centers. We present the updated information for primary pediatricians to utilize when counseling families with children confronted by progressive end-stage pulmonary or cardiovascular disease.

RECENT FINDINGS

We provide general guidelines to consider for referral, and discuss allocation of organs in children, information regarding standard treatment protocols, and survival outcomes.

SUMMARY

Lung transplantation is a worthwhile treatment option to consider in children with end-stage lung disease. The treatment is complex, but lung transplant provides substantial survival benefit and markedly improved quality of life for children and their families. This timely review provides comprehensive information for pediatricians who are considering options for treatment of children with end-stage lung disease.

Improving survival outcomes in lung transplant recipients through early detection of bronchiolitis obliterans: Daily home spirometry versus standard pulmonary function testing

BACKGROUND

Long-term lung transplant success is limited by bronchiolitis obliterans syndrome (BOS), a form of chronic allograft rejection that manifests in the majority of patients by five years post-transplant. Frequent monitoring of pulmonary function measurements through the use of daily home spirometry may have the capability to detect the onset of BOS sooner than standard pulmonary function testing. Early detection of BOS would confer a treatment advantage that may improve survival outcomes for lung transplant recipients.

METHODS

A systematic review of current evidence was used to determine the effectiveness of daily home spirometry as a BOS detection tool, in addition to its impact and survival outcomes. Articles were included in the present systematic review if they were randomized control studies and if their purpose(s) included investigation of spirometry as a BOS detection tool in lung transplant patients.

RESULTS

A primary search of databases yielded 115 unique citations, with an additional four citations identified through a secondary review of the reference lists of retrieved articles. After application of all inclusion and exclusion criteria through abstract and full-text review, eight randomized controlled trials were included in the review.

DISCUSSION

Forced expiratory volume in 1 s (FEV1) has been identified as the most reliable diagnostic tool for detecting the onset of BOS. Two studies compared the use of traditionally scheduled pulmonary function testing with daily home spirometry and found BOS stage 1 to appear 341 days earlier with home spirometry (P<0.001). Other studies that investigated the impact early detection had on survival showed a positive trend toward freedom from BOS and reduced rates of retransplantation, although these results did not reach statistical significance (P<0.07).

CONCLUSION

Daily home spirometry has been shown to lead to earlier detection and staging of BOS when compared with standard pulmonary function testing. Although FEV1 has been shown to be the most sensitive and reliable marker of BOS onset, the impact of earlier staging via home spirometry on survival has not been reliably determined.

A new classification system for chronic lung allograft dysfunction

Although survival after lung transplantation has improved significantly during the last decade, chronic rejection is thought to be the major cause of late mortality. The physiologic hallmark of chronic rejection has been a persistent fall in forced expiratory volume in 1 second associated with an obstructive ventilatory defect, for which the term bronchiolitis obliterans syndrome (BOS) was defined to allow a uniformity of description and grading of severity throughout the world. Although BOS was generally thought to be irreversible, recent evidence suggests that some patients with BOS may respond to azithromycin with > 10% improvement in their forced expiratory volume in 1 second. In addition, a restrictive form of chronic rejection has recently been described that does not fit the strict definition of BOS as an obstructive defect. Hence, the term chronic lung allograft dysfunction (CLAD) has been introduced to cover all forms of graft dysfunction, but CLAD has yet to be defined. We propose a definition of CLAD and a flow chart that may facilitate recognition of the different phenotypes of CLAD that can complicate the clinical course of lung transplant recipients.

Fitting and interpreting continuous-time latent Markov models for panel data

Multistate models characterize disease processes within an individual. Clinical studies often observe the disease status of individuals at discrete time points, making exact times of transitions between disease states unknown. Such panel data pose considerable modeling challenges. Assuming the disease process progresses accordingly, a standard continuous-time Markov chain (CTMC) yields tractable likelihoods, but the assumption of exponential sojourn time distributions is typically unrealistic. More flexible semi-Markov models permit generic sojourn distributions yet yield intractable likelihoods for panel data in the presence of reversible transitions. One attractive alternative is to assume that the disease process is characterized by an underlying latent CTMC, with multiple latent states mapping to each disease state. These models retain analytic tractability due to the CTMC framework but allow for flexible, duration-dependent disease state sojourn distributions. We have developed a robust and efficient expectation-maximization algorithm in this context. Our complete data state space consists of the observed data and the underlying latent trajectory, yielding computationally efficient expectation and maximization steps. Our algorithm outperforms alternative methods measured in terms of time to convergence and robustness. We also examine the frequentist performance of latent CTMC point and interval estimates of disease process functionals based on simulated data. The performance of estimates depends on time, functional, and data-generating scenario. Finally, we illustrate the interpretive power of latent CTMC models for describing disease processes on a dataset of lung transplant patients. We hope our work will encourage wider use of these models in the biomedical setting.

Bronchiolitis obliterans syndrome: the Achilles' heel of lung transplantation

Lung transplantation is a therapeutic option for patients with end-stage pulmonary disorders. Unfortunately, chronic lung allograft dysfunction (CLAD), most commonly manifest as bronchiolitis obliterans syndrome (BOS), continues to be highly prevalent and is the major limitation to long-term survival. The pathogenesis of BOS is complex and involves alloimmune and nonalloimmune pathways. Clinically, BOS manifests as airway obstruction and dyspnea that are classically progressive and ultimately fatal; however, the course is highly variable, and distinguishable phenotypes may exist. There are few controlled studies assessing treatment efficacy, but only a minority of patients respond to current treatment modalities. Ultimately, preventive strategies may prove more effective at prolonging survival after lung transplantation, but their remains considerable debate and little data regarding the best strategies to prevent BOS. A better understanding of the risk factors and their relationship to the pathological mechanisms of chronic lung allograft rejection should lead to better pharmacological targets to prevent or treat this syndrome.

Phenotyping established chronic lung allograft dysfunction predicts extracorporeal photopheresis response in lung transplant patients

Chronic lung allograft dysfunction (CLAD) remains the leading cause of mortality in lung transplant recipients after the first year. Treatment remains limited and unpredictable. Existing data suggests extracorporeal photopheresis (ECP) may be beneficial. This study aimed to identify factors predicting treatment response and the prognostic implications. A single center retrospective analysis of all patients commencing ECP for CLAD between November 1, 2007 and September 1, 2011 was performed. In total 65 patients were included, 64 of whom had deteriorated under azithromycin. Median follow-up after commencing ECP was 503 days. Upon commencing ECP, all patients were classified using proposed criteria for emerging clinical phenotypes, including "restrictive allograft syndrome (RAS)", "neutrophilic CLAD (nCLAD)" and "rapid decliners". At follow-up, 8 patients demonstrated ≥10% improvement in FEV1 , 27 patients had stabilized and 30 patients exhibited ≥10% decline in FEV1 . Patients fulfilling criteria for "rapid decliners" (n=21, p=0.005), RAS (n=22, p=0.002) and those not exhibiting neutrophilia in bronchoalveolar lavage (n=44, p=0.01) exhibited poorer outcomes. ECP appears an effective second line treatment in CLAD patients progressing under azithromycin. ECP responders demonstrated improved progression-free survival (median 401 vs. 133 days). Proposed CLAD phenotypes require refinement, but appear to predict the likelihood of ECP response.

Critical role for IL-17A/F in the immunopathogenesis of obliterative airway disease induced by Anti-MHC I antibodies

BACKGROUND

The IL-17 axis is implicated in pathogenesis of chronic rejection after human lung transplantation. Using a murine model of obliterative airway disease (OAD), we recently demonstrated that Abs to MHC class I antigens can induce immune responses to self-antigens that contributes to immunopathogenesis of chronic rejection. Using a murine model of OAD, we determined the role of IL-17 family members in induction of autoimmunity leading to OAD after ligation of MHC class I.

METHODS

Anti-MHC class I or control antibodies (Abs) were administered intrabronchially to wild-type (WT) and IL-17a knock out (IL-17A-/-) C57BL/6.

RESULTS

By day 30, anti-MHC I administered endobronchially in IL-17A-/- mice demonstrated significant reduction in cellular infiltration, a 36.8% reduction in CD4 T cells, 62.7% in CD11b macrophages, 37.5% in degree of fibrosis, 1.94 fold and 2.17 fold decrease in anti-KAT and anti-Col-V, respectively, when compared with wild-type mice. Analysis of lung infiltrating cells in anti-MHC I WT revealed increase in IL-17A (KAT:92+21,Col-V:103+19spm) and IL-17F (KAT:5.03%,Col-V:2.75%) secreting CD4+ T cells. However, administration of anti-MHC I in IL-17A-/- demonstrated increase only in IL-17F for KAT (13.70%) and Col-V (7.08%). Anti-IL-17(A-F) mAb administration after anti-MHC I abrogated OAD in both WT and IL-17A-/-.

CONCLUSION

Our findings indicate that IL-17A and IL-17F secreted by CD4+Th17 cells specific to lung self-antigens are critical mediators of autoimmunity leading to the pathogenesis of OAD.

Time-dependent changes in the risk of death in pure bronchiolitis obliterans syndrome (BOS)

BACKGROUND

The timing of disease onset may affect the prognosis in chronic lung allograft dysfunction (CLAD). The relationship between the timing of disease onset and the prognosis of CLAD and its sub-types, bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS), was examined.

METHODS

Clinical records and pulmonary function data of 597 patients who underwent bilateral lung transplantation from 1996 to 2010 and survived for >3 months were examined.

RESULTS

Among 155 patients with a final diagnosis of BOS, patient survival after disease onset was significantly different according to disease-onset timing (BOS onset/post-BOS median survival: overall/1,438 days; <1 year/511 days; 1-2 years/1,199 days; 2-3 years/1,403 days; >3 years/did not reach median survival; p < 0.0001). The prognosis of RAS was generally poorer than that of BOS (overall post-RAS median survival, 377 days). Treating non-CLAD, CLAD, BOS, and RAS as time-dependent covariates, recipient sex-adjusted and age-adjusted Cox regression analysis demonstrated an overall mortality risk of BOS (reference: no CLAD) of 6.7 (95% confidence interval, 4.6-9.9). However, when patients survived 3 years without CLAD, the mortality risk of subsequent BOS was only 1.9 (95% confidence interval, 0.8-4.4) compared with no CLAD. The number of RAS patients was too small to obtain sufficient power to estimate time-dependent mortality risk.

CONCLUSION

Late-onset BOS showed a better prognosis than early-onset BOS. Studies that do not distinguish BOS from RAS may overestimate the mortality risk of BOS. Multicenter studies will be required to further elucidate risk factors toward the development of better management strategies for CLAD.

Bronchiolitis Obliterans Syndrome and Chronic Lung Allograft Dysfunction: Evolving Concepts and Nomenclature

Bronchiolitis obliterans syndrome (BOS) eventually occurs in the majority of lung transplant recipients who survive beyond 1 year, can greatly impair quality of life, and is, directly or indirectly, the major cause of delayed allograft dysfunction and recipient death. A number of associated events or conditions are strongly associated with the risk for developing BOS; these include acute rejection, gastroesophageal reflux, infections, and autoimmune reactions that can occur in the setting of alloimmune responses to the lung allograft as recipients are given intense immunosuppression to prevent allograft rejection. The term chronic lung allograft dysfunction (CLAD) is being increasingly used to refer to recipients with late allograft dysfunction that meets the spirometric criteria for the diagnosis of BOS, but clinicians should recognize that such dysfunction can occur for a variety of reasons other than BOS. The recently identified entity of restrictive allograft syndrome, which is now recognized as a relatively distinct phenotype of CLAD, has features that differentiate it from classic obstructive BOS. A number of other entities that can also significantly affect allograft function must also be considered when significant allograft dysfunction is encountered following lung transplantation.

Decline in 25% to 75% forced expiratory flow as an early predictor of chronic airway rejection in pediatric lung transplant recipients

BACKGROUND

Bronchiolitis obliterans (BO) is the major obstacle to long-term lung allograft viability. Its clinical correlate, BO syndrome (BOS), is defined as a decline of at least 20% in forced expiratory volume in 1 second (FEV(1)) from baseline. BOS is often diagnosed after significant organ dysfunction has occurred. Because BO is a small-airways disease, we hypothesized that a 20% decline in the 25% to 75% forced expiratory flow (FEF(25-75)) from baseline should occur before a decline in FEV(1) and should predict progression to BOS with high sensitivity and specificity.

METHODS

Pulmonary function tests and records of pediatric lung transplantation patients at Texas Children's Hospital from 2002 to 2007 were reviewed. Declines in FEV(1) and FEF(25-75) from the best post-transplant baseline values were recorded and analyzed. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

Thirty-one patients were eligible for the study. In 11 BOS patients, the mean±standard deviation number of days from transplant until a 20% decline in FEV(1) was 896.5±400 compared with 728.0±475 (p = 0.022) until a 20% decline in FEF(25-75) was reached. The sensitivity, specificity, and positive predictive and negative predictive values of a 20% reduction in FEF(25-75) in determining BOS were 100%, 90.0%, 84.6%, and 100%, respectively.

CONCLUSIONS

All patients who developed BOS had a decline in FEF(25-75) at or before the decline in FEV(1). The reduction in FEF(25-75) occurred statistically significantly earlier than the decline in FEV(1), by an average of 168.5 days. This decline in FEF(25-75) was also highly sensitive and specific for the diagnosis of BOS.