Analysis of risk factors for the development of bronchiolitis obliterans syndrome

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.

Update on Bronchiolitis Obliterans Syndrome in Lung Transplantation

Lung transplantation has become an important therapeutic option for patients with end-stage organ dysfunction; however, its clinical usefulness has been limited by the relatively early onset of chronic allograft dysfunction and progressive clinical decline. Obliterative bronchiolitis is characterized histologically by luminal fibrosis of the respiratory bronchioles and clinically by bronchiolitis obliterans syndrome (BOS) which is defined by a measured decline in lung function based on forced expiratory volume (FEV₁). Since its earliest description, a number of risk factors have been associated with the development of BOS, including acute rejection, lymphocytic bronchiolitis, primary graft dysfunction, infection, donor specific antibodies, and gastroesophageal reflux disease. However, despite this broadened understanding, the pathogenesis underlying BOS remains poorly understood and once begun, there are relatively few treatment options to battle the progressive deterioration in lung function.

Mechanistic differences between phenotypes of chronic lung allograft dysfunction after lung transplantation

Distinct phenotypes of chronic lung allograft dysfunction (CLAD) after lung transplantation are emerging with lymphocytic bronchiolitis (LB)/azithromycin reversible allograft dysfunction (ARAD), classical or fibrotic bronchiolitis obliterans syndrome (BOS), and restrictive allograft syndrome (RAS) proposed as separate entities. We have additionally identified lung transplant recipients with prior LB, demonstrating persistent airway neutrophilia (PAN) despite azithromycin treatment. The aim of this study was to evaluate differences in the airway microenvironment in different phenotypes of CLAD. Bronchoalveolar lavage (BAL) from recipients identified as stable (control), LB/ARAD, PAN, BOS, and RAS were evaluated for differential cell counts and concentrations of IL-1α, IL-1β, IL-6, IL-8, and TNF-α. Primary human bronchial epithelial cells were exposed to BAL supernatants from different phenotypes and their viability measured. BOS and RAS showed increased BAL neutrophilia but no change in cytokine concentrations compared with prediagnosis. In both LB/ARAD and PAN, significant increases in IL-1α, IL-1β, and IL-8 were present. BAL IL-6 and TNF-α concentrations were increased in PAN and only this phenotype demonstrated decreased epithelial cell viability after exposure to BAL fluid. This study demonstrates clear differences in the airway microenvironment between different CLAD phenotypes. Systematic phenotyping of CLAD may help the development of more personalized approaches to treatment.

Conventional vs. tablet computer-based patient education following lung transplantation--a randomized controlled trial

BACKGROUND

Accurate immunosuppression is of critical importance in preventing rejection, while avoiding toxicity following lung transplantation. The mainstay immunosuppressants are calcineurin inhibitors, which require regular monitoring due to interactions with other medications and diet. Adherence to immunosuppression and patient knowledge is vital and can be improved through patient education. Education using tablet-computers was investigated.

OBJECTIVE

To compare tablet-PC education and conventional education in improving immunosuppression trough levels in target range 6 months after a single education. Secondary parameters were ratio of immunosuppression level measurements divided by per protocol recommended measurements, time and patient satisfaction regarding education.

DESIGN

Single-centre, open labelled randomised controlled trial.

PARTICIPANTS

Patients >6 months after lung-transplantation with <50% of calcineurin inhibitor trough levels in target range.

INTERVENTION

Tablet-pc education versus personal, nurse-led education.

MEASUREMENTS

Calcineurin inhibitor levels in target range 6 months after education, level variability, interval adherence, knowledge and adherence was studied. As outcome parameter, renal function was measured and adverse events registered.

RESULTS

Sixty-four patients were 1:1 randomised for either intervention. Levels of immunosuppression 6 months after education were equal (tablet-PC 58% vs. conventional 48%, p = 0.27), both groups improved in achieving a CNI trough level within target range by either education method (delta tablet-PC 29% vs. conventional 20%). In all patients, level variability decreased (-20.4%), whereas interval adherence remained unchanged. Knowledge about immunosuppression improved by 7% and compliance tests demonstrated universal improvements with no significant difference between groups.

CONCLUSION

Education is a simple, effective tool in improving adherence to immunosuppression. Tablet-PC education was non-inferior to conventional education.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01398488 http://clinicaltrials.gov/ct2/show/NCT01398488? term=gottlieb+tablet+pc+education&rank=1.

Lower incidence of CMV infection and acute rejections with valganciclovir prophylaxis in lung transplant recipients

Background

Cytomegalovirus (CMV) is the most common opportunistic infection following lung transplantation. CMV replication in the lung allograft is described as accelerating the development of bronchiolitis obliterans syndrome (BOS). Finding a strategy to prevent CMV infection is an important issue.

Methods

We performed a retrospective, single-centre study of 114 lung transplant recipients (LTRs) who underwent lung transplantation from January 2001 to December 2006. In a smaller cohort of 88 CMV seropositive (R+) LTRs, three months of valganciclovir prophylaxis (2004-2006) was compared to three months of oral ganciclovir (2001-2003) with respect to the incidence of CMV infection/disease, the severity of CMV disease, acute rejection, BOS-free 4 year survival and 4 year survival. In the whole group of 114 LTRs the impact of CMV infection on long-term survival (BOS free 4 year survival and 6 year survival) was assessed.

Results

For the cohort of 88 CMV seropositive LTRs, the incidence of CMV infection/disease at one year was lower in the valganciclovir group compared to the ganciclovir group (24% vs. 54%, p = 0.003). There was a tendency towards reduced CMV disease, from 33% to 20% and a significant lower incidence of asymptomatic CMV infection (22% vs. 4%, p = 0.005). A lower incidence of acute rejection was observed in the valganciclovir group. However, there was no significant difference between the two groups in BOS free 4 year survival and 4 year survival.

For the entire group of 114 LTRs, BOS-free 4 year survival for recipients with CMV disease was (32%, p = 0.005) and among those with asymptomatic CMV infection (36%, p = 0.061) as compared with patients without CMV infection (69%). Six year survival was lower among patients with CMV disease, (64%, p = 0.042) and asymptomatic CMV infection (55%, p = 0.018) than patients without CMV infection (84%).

Conclusions

A lower incidence of CMV infection/disease and acute rejections was observed with valganciclovir (3 months) when compared to oral ganciclovir (3 months). The long-term impact of CMV infection/disease was significant for BOS-free survival and survival.

Impact of cytokine expression in the pre-implanted donor lung on the development of chronic lung allograft dysfunction subtypes

The long-term success of lung transplantation continues to be challenged by the development of chronic lung allograft dysfunction (CLAD). The purpose of this study was to investigate the relationship between cytokine expression levels in pre-implanted donor lungs and the posttransplant development of CLAD and its subtypes, bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). Of 109 patients who underwent bilateral lung or heart-lung transplantation and survived for more than 3 months, 50 BOS, 21 RAS and 38 patients with No CLAD were identified by pulmonary function test results. Using donor lung tissue biopsies sampled from each patient, expression levels of IL-6, IL-1β, IL-8, IL-10, interferon-γ and tumor necrosis factor-α mRNA were measured. IL-6 expression levels were significantly higher in pre-implanted lungs of patients that ultimately developed BOS compared to RAS and No CLAD (p = 0.025 and 0.011, respectively). Cox regression analysis demonstrated an association between high IL-6 expression levels and BOS development (hazard ratio = 4.98; 95% confidence interval = 2.42-10.2, p < 0.001). In conclusion, high IL-6 mRNA expression levels in pre-implanted donor lungs were associated with the development of BOS, not RAS. This association further supports the contention that early graft injury impacts on both late graft function and early graft function.

Interobserver variability in grading transbronchial lung biopsy specimens after lung transplantation

BACKGROUND

Acute rejection remains a major source of morbidity after lung transplantation. Given the importance of this diagnosis, an international grading system was developed to standardize the diagnosis of acute lung-allograft rejection. The reliability of this grading system has not been adequately assessed by previous studies.

METHODS

We examined the level of agreement in grading transbronchial biopsy specimens obtained from a large multicenter study (AIRSAC [Comparison of a Tacrolimus/Sirolimus/Prednisone Regimen vs Tacrolimus/Azathioprine/Prednisone Immunosuppressive Regimen in Lung Transplantation] trial). Biopsy specimens were initially graded for acute rejection and lymphocytic bronchiolitis by the site pathologist and subsequently graded by a central pathologist. Reliability of interobserver grading was evaluated using Cohen κ coefficients.

RESULTS

A total of 481 transbronchial biopsy specimens were graded by both the site and central pathologists. The overall concordance rates were 74% and 89% for grade A and grade B biopsy specimens, respectively. When samples from biopsies performed at different time points after transplantation were assessed, there was a higher level of agreement early (≤ 6 weeks) after transplant compared with later time points for acute rejection. However, there was still only moderate agreement for both grade A (κ score 0.479; 95% CI, 0.29-0.67) and grade B (κ score 0.465; 95% CI, 0.08-0.85) rejection.

CONCLUSIONS

These results expand upon previous reports of interobserver variability in grading transbronchial biopsy specimens after lung transplantation. Given the variability in grading these specimens, we advocate further education of the histopathologic findings in lung transplant biopsy specimens, as well as revisiting the current criteria for grading transbronchial biopsy specimens to improve concordance among lung transplant pathologists.

TRIAL REGISTRY

ClinicalTrials.gov; No. NCT00321906; URL: www.clinicaltrials.gov.

Impaired exercise capacity after lung transplantation is related to delayed recovery of muscle strength

Lung transplant recipients report reduced exercise capacity despite satisfactory graft function. We analysed changes in lung function, six-min walk distance (6MWD), and quadriceps strength in the first 26-wk post-transplant and examined what factors predict 6MWD recovery. All lung transplant recipients at a single institution between June 2007 and January 2011 were considered for inclusion. Lung function, 6MWD, and quadriceps strength corrected for body weight (QS%) were recorded pre- and two-, six-, 13-, and 26-wk post-transplant. Fifty recipients, of mean (± SD) age 42 (± 13) yr, were studied. Mean FEV1 % and 6MWD improved from 26.4% to 88.9% and from 397 to 549 m at 26 wk, respectively (both p < 0.001). QS% declined in the first two wk but had improved to above pre-transplant levels by 26 wk (p = 0.027). On multivariate analysis (n = 35), lower pre-transplant exercise capacity and greater recovery in muscle strength explained most of the improvement in exercise capacity. Delayed recovery of exercise capacity after lung transplantation is unrelated to delay in improvement in graft function, but occurs secondary to the slow recovery of muscle strength. Our findings show that additional controlled trials are needed to better understand the influence of exercise rehabilitation on improvement in exercise capacity post-transplantation.

Lentivirus IL-10 gene therapy down-regulates IL-17 and attenuates mouse orthotopic lung allograft rejection

The purpose of the study was to examine the effect of lentivirus-mediated IL-10 gene therapy to target lung allograft rejection in a mouse orthotopic left lung transplantation model. IL-10 may regulate posttransplant immunity mediated by IL-17. Lentivirus-mediated trans-airway luciferase gene transfer to the donor lung resulted in persistent luciferase activity up to 6 months posttransplant in the isograft (B6 to B6); luciferase activity decreased in minor-mismatched allograft lungs (B10 to B6) in association with moderate rejection. Fully MHC-mismatched allograft transplantation (BALB/c to B6) resulted in severe rejection and complete loss of luciferase activity. In minor-mismatched allografts, IL-10-encoding lentivirus gene therapy reduced the acute rejection score compared with the lentivirus-luciferase control at posttransplant day 28 (3.0 ± 0.6 vs. 2.0 ± 0.6 (mean ± SD); p = 0.025; n = 6/group). IL-10 gene therapy also significantly reduced gene expression of IL-17, IL-23, and retinoic acid-related orphan receptor (ROR)-γt without affecting levels of IL-12 and interferon-γ (IFN-γ). Cells expressing IL-17 were dramatically reduced in the allograft lung. In conclusion, lentivirus-mediated IL-10 gene therapy significantly reduced expression of IL-17 and other associated genes in the transplanted allograft lung and attenuated posttransplant immune responses after orthotopic lung transplantation.

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.

Tacrolimus versus cyclosporin as primary immunosuppression for lung transplant recipients

BACKGROUND

Lung transplantation is a well-accepted treatment for people with most end-stage lung diseases. Although both tacrolimus and cyclosporin are used as primary immunosuppressive agents in lung transplant recipients, it is unclear which of these drugs is better in reducing rejection and death without causing adverse effects.

OBJECTIVES

To assess the benefits and harms of tacrolimus versus cyclosporin for primary immunosuppression in lung transplant recipients.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 10 April 2013 through contact with the Trials Search Co-ordinator using search terms relevant to this review. We also searched Science Citation Index Expanded and the Transplant Library to 20 April 2013.

SELECTION CRITERIA

We included all randomised controlled trials (RCT) that compared any dose and duration of administration of tacrolimus versus cyclosporin as primary immunosuppressive treatment in lung transplant recipients. Our selection criteria required that all included patients received the same additional immunosuppressive therapy within each study.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. For dichotomous data we used risk ratio (RR) and used mean difference (MD) for continuous data, each with 95% confidence intervals (CI). Methodological components of the included studies were used to assess risk of systematic errors (bias). Trial sequential analysis was used to assess risk of random errors (play of chance).

MAIN RESULTS

We included three studies that enrolled a total of 413 adult patients that compared tacrolimus with microemulsion or oral solution cyclosporin. All studies were found to be at high risk of bias. Tacrolimus seemed to be significantly superior to cyclosporin regarding the incidence of bronchiolitis obliterans syndrome (RR 0.46, 95% CI 0.29 to 0.74), lymphocytic bronchitis score (MD -0.60, 95% CI -1.04 to -0.16), treatment withdrawal (RR 0.27, 95% CI 0.16 to 0.46), and arterial hypertension (RR 0.67, 95% CI 0.50 to 0.89). However, the finding for arterial hypertension was not confirmed when analysed using a random-effects model (RR 0.54, 95% CI 0.17 to 1.73). Furthermore, trial sequential analysis found that none of the meta-analyses reached the required information sizes and cumulative Z-curves did not cross trial sequential monitoring boundaries. Diabetes mellitus occurred more frequently among people in the tacrolimus group compared with the cyclosporin group when the fixed-effect model was applied (RR 4.24, 95% CI 1.58 to 11.40), but no difference was found when the random-effects model was used for analysis (RR 4.43, 95% CI 0.75 to 26.05). Again, trial sequential analysis found that the required information threshold was not reached and cumulative Z-curve did not cross the trial sequential monitoring boundary. No significant difference between treatment groups was observed regarding mortality (RR 1.06, 95% CI 0.75 to 1.49), incidence of acute rejection (RR 0.89, 95% CI 0.77 to 1.03), numbers of infections/100 patient-days (MD -0.15, 95% CI -0.30 to 0.00), cancer (RR 0.21, 95% CI 0.04 to 1.16), kidney dysfunction (RR 1.41, 95% CI 0.93 to 2.14), kidney failure (RR 1.57, 95% CI 0.28 to 8.94), neurotoxicity (RR 7.06, 95% CI 0.37 to 135.19), and hyperlipidaemia (RR 0.60, 95% CI 0.30 to 1.20). Trial sequential analysis showed the required information thresholds were not reached for any of these outcome measures.

AUTHORS' CONCLUSIONS

Tacrolimus may be superior to cyclosporin regarding bronchiolitis obliterans syndrome, lymphocytic bronchitis, treatment withdrawal, and arterial hypertension, but may be inferior regarding development of diabetes. No difference in mortality and acute rejection was observed between patients treated with tacrolimus and cyclosporin. There were few studies comparing tacrolimus and cyclosporin after lung transplantation, and the numbers of patients and events in the included studies were limited. Furthermore, the included studies were deemed to be at high risk of bias. Hence, more RCTs are needed to assess the results of the present review. Such studies ought to be conducted with low risks of systematic errors (bias) and of random errors (play of chance).

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.

SaLUTaRy: survey of lung transplant rejection

BACKGROUND

The International Society for Heart and Lung Transplantation (ISHLT) guidelines on the interpretation of lung rejection in pulmonary allograft biopsy specimens were revised most recently in 2007. The goal of our study was to determine how these revisions, along with nuances in the interpretation and application of the guidelines, affect patient care.

METHODS

A Web-based survey was e-mailed to pathologists and pulmonologists identified as being part of the lung transplant team at institutions in the United States with active lung transplant programs as determined from the Organ Procurement and Transplantation Network Web site (http://optn.transplant.hrsa.gov/members/directory.asp).

RESULTS

Grades B1 and B2 in asymptomatic patients would fall into the same treatment group under the 2007 classification, which combines B1 and B2 into B1R. Also, some pulmonologists would not interpret a pathologic diagnosis of lymphocytic bronchiolitis as grade B rejection, resulting in under-treatment of these patients. Regarding bronchiolitis obliterans, most pulmonologists would treat the patient differently if there were an active mononuclear inflammatory infiltrate, and most pathologists would comment on the presence of such an infiltrate, contrary to the 2007 guidelines, which discourage reporting this infiltrate. We also found discrepancies among pathologists in their interpretation of airway lymphocytic infiltrates, whether eosinophils can be present in bronchial-associated lymphoid tissue, and whether airway inflammation represents rejection or bacterial infection.

CONCLUSIONS

The issue of grading and treating airway inflammation in pulmonary allograft biopsy specimens continues to be problematic, despite revised ISHLT guidelines. Clarification of guidelines for pathologists and pulmonologists using evidence-based criteria could lead to improved communication and patient care.

Implementing a standardized, evidence-based education program using the patient's electronic file for lung transplant recipients

CONTEXT

Patient education is crucial to guarantee that transplant recipients are capable of adequate self-management. Until recently, our education program to prepare lung transplant patients for discharge lacked a systematic approach, meaning that it was unclear whether all key information had been provided and whether the patient understood the information. A lack of coordination among the multidisciplinary team members also was apparent.

OBJECTIVES

(1) To map out a structured education program, outlining the content, process, and evaluation of education for patients before discharge after lung transplant; (2) to integrate this program into the patient's electronic file and pilot test this new form of education tracking.

METHODS

We used the conceptual framework of Lorig and colleagues, as well as the educational leaflets of the International Transplant Nurses Society, to generate the content of our education program. The interdisciplinary lung transplant team decided when and by whom each educational component should be provided, as well as the evaluation criteria. Next, information technology engineers integrated this educational program into the patient's electronic file. Nurses subsequently tested the program, and their feedback was integrated in the next version of the program.

RESULTS

Health care providers experienced a higher level of uniformity and transparency. After using the education program, most patients indicated that they felt confident to go home.

CONCLUSION

Our electronic educational platform is promising, yet further testing is necessary to evaluate whether patients indeed have sufficient knowledge and show adequate self-management skills in the long term after transplant.

Bronchiolitis

Bronchiolitis is a disease of the small airways accompanied by progressive and often irreversible airflow obstruction. Bronchiolitis can have several causes such as infection, toxic exposure, collagen vascular disease, post lung and stem cell transplant, and idiopathic etiology. Symptoms of cough and sputum production are often mistaken for chronic obstructive pulmonary disease or asthma, leading to a delay in diagnosis. Unfortunately, many types of bronchiolitis do not improve with therapy. Bronchiolitis following lung and stem cell transplant are the most common types seen in adults, and provide important insights into its pathogenesis.

Sublingual Tacrolimus for Immunosuppression in Lung Transplantation

Lung transplantation has emerged as an option to prolong and increase the quality of life in patients with end-stage pulmonary lung disease. In lung transplant recipients, because of the high potential for acute and chronic allograft rejection, optimal selection, dosage and delivery of immunosuppressive medications is critical. Cystic fibrosis (CF), a multi-organ system disease that often includes pulmonary and gastrointestinal manifestations, represents the leading indication for bilateral lung transplantation. The gastrointestinal manifestations of CF, however, confound post-transplant management by causing significant variation in the rate and extent of absorption of orally administered immunosuppressive medications. Tacrolimus, a new calcineurin inhibitor, is increasingly employed as the primary immunosuppressive agent in lung transplant recipients. Unfortunately, tacrolimus itself exhibits variable bioavailability, particularly in CF transplant recipients. A novel approach to the absorption dilemma is administration of tacrolimus via the sublingual (SL) route. Little published information exists concerning the use of SL immunosuppression in transplant recipients. However, emerging evidence suggests that SL tacrolimus provides is an effective means of drug delivery particularly for CF lung transplant recipients. Preliminary results from a pilot study, demonstrate that SL delivery of tacrolimus achieves therapeutic serum levels, in lung transplant recipients with CF, over the first few postoperative months. In addition, the early postoperative use of SL tacrolimus has been associated with acceptable rates of transplant rejection and normal renal function in a cohort of 22 lung transplant recipients that included CF and non-CF transplant recipients. Potential pharmacokinetic advantages of the SL route of delivery include good permeability, rapid absorption, acceptable bioavailability and easy accessibility. From an economic standpoint, considerable cost savings could be achieved by using the SL rather than the intravenous route of drug delivery for tacrolimus. Comparative, prospective randomized trials are necessary to evaluate the long-term safety and efficacy of SL tacrolimus in lung transplant patients. Until such data are available, the use of SL tacrolimus should be considered in situations where alternative routes of delivery are unavailable or as part of ongoing research studies. Ultimately, SL tacrolimus may prove efficacious for short-term use in the early postoperative lung transplant recipients, particularly in patients with malabsorption problems such as CF transplant recipients.

Cumulative exposure to CD8+ granzyme Bhi T cells is associated with reduced lung function early after lung transplantation

Outcomes following lung transplant remain suboptimal. This is attributable to variable posttransplant recovery of lung function, and inconsistent degrees of lung function loss after peak function is reached. Granzyme B is elevated in the blood and bronchoalveolar lavage (BAL) in acute rejection. We hypothesized that persistent exposure to T cells high in granzyme B would negatively correlate with lung function. We investigated cumulative exposure measured as the area-under-the-curve (AUC) of CD8+ T cell granzyme Bhi cells in the first year posttransplant in both BAL and blood in 24 transplant recipients. We assessed the correlation between cumulative 1-year exposure and FEV1 slope. There was a negative correlation between 1-year exposure and FEV1 slope within the first year (r=-0.63; P=.001). This relationship persisted even when adjusted for transplant type, gender, age, rejection, and indication for transplantation. In contrast, no relationship was seen with the 1-year AUC and lung function after 1 year posttransplant. In contrast to the BAL granzyme Bhi levels, granzyme Bhi levels from the blood showed no relationship with lung function. These findings suggest that CD8+ T-cell-driven factors are responsible for early improvements in lung function after transplantation.

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.

Timing of basiliximab induction and development of acute rejection in lung transplant patients

BACKGROUND

Acute rejection affects more than 36% of recipients within the first year post-transplantation. The interleukin-2 (IL-2) receptor antagonist basiliximab has been associated with decreased frequency and severity of acute rejection. We investigated whether the timing of induction administration would impact the frequency and severity of acute rejection in the first year after transplantation.

METHODS

In this study we reviewed 119 patients who underwent lung transplantation at Henry Ford Hospital from October 1994 to January 2009. Prior to January 2000 no patients received induction. From January 2000 to March 2006 the initial dose was given after implantation, and from March 2006 to 2009 basiliximab was given prior to implantation. The primary outcome was cumulative acute rejection score (CAR) in the first post-operative year comparing post- vs pre-implant induction.

RESULTS

The CAR score for pre-implant basiliximab was 2.5 ± 2.3. This was significantly lower than CAR score of 4.6 ± 3.9 in the post-implant group (p = 0.025). The no-induction group had the highest CAR score at 6.3 ± 3.8 (p = 0.077 compared with the post group). The mean follow-up times in the post and pre group were 5.9 ± 2.3 and 2.3 ± 0.7 years, respectively (p < 0.001). There was no difference in freedom from bronchiolitis obliterans syndrome (BOS), survival or invasive infections between pre- and post-implant induction groups.

CONCLUSIONS

Basiliximab prior to implant is associated with a lower cumulative acute rejection score over 1 year compared with induction post-implantation. Despite a lower cumulative acute rejection score, there was no significant difference in freedom from BOS or survival.

A review of bronchiolitis obliterans syndrome and therapeutic strategies

Lung transplantation is an important treatment option for patients with advanced lung disease. Survival rates for lung transplant recipients have improved; however, the major obstacle limiting better survival is bronchiolitis obliterans syndrome (BOS). In the last decade, survival after lung retransplantation has improved for transplant recipients with BOS. This manuscript reviews BOS along with the current therapeutic strategies, including recent outcomes for lung retransplantation.

Chronic allograft dysfunction

Chronic, progressive, and irreversible loss of lung function is the major medium-term and long-term complication after lung transplantation and the leading cause of death. Over the past decade, progress has been made in understanding the pathogenesis of bronchiolitis obliterans. Alloimmune factors and nonalloimmune factors may contribute to its development. Understanding the precise mechanism of each type of chronic allograft dysfunction may open up the field for new preventive and therapeutic interventions. This article reviews major new insights into the clinical aspects, pathophysiology, risk factors, diagnosis, and management of chronic allograft dysfunction after lung transplantation.

Neutralizing IL-17 prevents obliterative bronchiolitis in murine orthotopic lung transplantation

Obliterative bronchiolitis (OB) is the key impediment to the long-term survival of lung transplant recipients and the lack of a robust preclinical model precludes examining OB immunopathogenesis. In the current study, lungs from C57BL/10 H-2(b) mice that are MHC compatible, but minor histocompatability antigen incompatible, were transplanted into C57BL/6 mice. Histological features and cytokine profiles of OB were assessed. Moderate rejection (grade A3) developed by day 14, with evidence of OB at that time point. At 21 days, OB was present in 55% of grafts and moderate to severe rejection (grade A3-A4) was present in all mice. At 28 days, OB was present in 44% of mice and severe rejection (grade A4) was present in all. IL-17A, but not IL-17F, splenic mRNA transcripts and serum protein levels were increased only in mice that developed OB, whereas IL-10 transcripts and protein were increased only in non-OB mice. Neutralizing IL-17 prevented OB, down regulated acute rejection, and upregulated systemic IL-10. Collectively, these data show that transplantation of minor histoincompatible lungs from C57BL/10 mice into C57BL/6 mice results in a highly reproducible preclinical model of OB. In addition, these data indicate that neutralizing IL-17A or augmenting IL-10 could be therapeutic interventions to prevent OB.

Five-year outcomes with alemtuzumab induction after lung transplantation

BACKGROUND

Induction therapy with alemtuzumab, followed by lower than conventional intensity post-transplant immunosuppression (eg, tacrolimus monotherapy), has been associated with reduced morbidity and mortality in abdominal and heart transplantation. We examined 5-year outcomes in lung recipients receiving alemtuzumab in conjunction with reduced-intensity post-transplant immunosuppression (early lower-dose tacrolimus; lower-dose steroids, with or without mycophenolate mofetil), compared with lung recipients receiving other induction agents or no induction in association with post-transplant immunosuppression.

METHODS

A retrospective analysis was performed using prospectively collected data from a single-site clinical database of 336 lung recipients (aged ≥ 18) who received allografts between 1998 and 2005, classified by induction type: alemtuzumab, 127; Thymoglobulin, 43; daclizumab, 73; and none, 93. Survival analyses examined patient and graft survival, and freedom from acute cellular rejection (ACR), lymphocytic bronchiolitis, obliterative bronchiolitis (OB), bronchiolitis obliterans syndrome (BOS), and post-transplant lymphoproliferative disorder (PTLD).

RESULTS

Five-year patient and graft survival differed by group (p = 0.046, p = 0.038, respectively). Alemtuzumab patient/graft survival rates were 59%/59%. Survival rates were 60%/44% for Thymoglobulin, 47%/46% for no induction, and 44%/41% for daclizumab. Freedom from ACR, lymphocytic bronchiolitis, OB, and BOS differed by group (all values, p < 0.008); alemtuzumab recipients showed greater 5-year freedom from each outcome (30%/82%/86%/54%) than Thymoglobulin (20%/54%/62%/27%), daclizumab (19%/55%/70%/43%), and no-induction groups (18%/70%/69%/46%). The groups did not differ in PTLD rates (≥ 94% free of PTLD at 5 years; p = 0.864). Effects were unchanged after controlling for potential covariates.

CONCLUSIONS

Alemtuzumab induction may be associated with improved outcomes in lung transplantation. Randomized controlled trials are needed to establish any effects of this agent.

Pulmonary complications of lung transplantation

Lung transplantation is an effective treatment option for select patients with a variety of end-stage lung diseases. Although transplant can significantly improve the quality of life and prolong survival, a myriad of pulmonary complications may result in significant morbidity and limit long-term survival. The recognition and early treatment of these complications is important for optimizing outcomes. This article provides an overview and update of the pulmonary complications that may be commonly encountered by pulmonologists caring for these patients.

Relevance of GERD in lung transplant patients

Lung transplantation has become a valuable treatment for end-stage pulmonary disorders in an attempt to improve quality of life and extend survival. Development of chronic rejection, also known as bronchiolitis obliterans syndrome (BOS), is responsible for the vast majority of deaths after lung transplantation. Up to 50% of lung transplant patients develop BOS within the first 5 years after transplantation. A high prevalence of gastroesophageal reflux and aspiration of gastric components has been described after lung transplantation. Reflux and aspiration have been implicated in the development of BOS and antireflux surgery has been proposed; however, the causal relationship with BOS and the impact of reflux in lung transplantation survival needs to be further elucidated.

Bronchiolitis obliterans syndrome development in lung transplantation patients

The main cause of death in lung transplantation patients is chronic rejection, known as bronchiolitis obliterans syndrome (BOS). There are many variables associated with its appearance. The aim of this study was to identify factors associated with BOS and its impact on survival among lung transplantation patients.

METHODS

We retrospectively analyzed charts of lung transplant patients from 1999 to 2009, evaluating survival, BOS, and associated factors.

RESULTS

Fifty-six patients have been transplanted with a 5-year survival of 55%. Eighteen (32%) developed BOS, at a mean age at diagnosis of 57 years (range 16-74). According to BOS classification, seven patients (38.8%) were type 2 and six (33.3%) type 3. Half the patients developed BOS at a mean of 8.5 months after transplantation with a mean survival of 18.5 months (range 2-61). Among the factors analyzed, 13 patients (72%) displayed acute cellular rejection and nine (50%) gastroesophageal reflux disease (GERD) diagnosed by pHmetry, both of which were significantly associated with BOS (P = .005). Among seven lung transplantation patients with invasive cytomegalovirus disease, the four who developed BOS (P = .04) showed the worst survival (P = .05). Four of the six patients with severe BOS (66.6%) died at a mean of 10.6 months after the diagnosis. The main cause of death was respiratory insufficiency.

CONCLUSIONS

BOS was associated with worse survival. The presence of acute cellular rejection episodes, CMV disease, and GERD were factors associated with chronic lung rejection.

Surgical correction of gastroesophageal reflux in lung transplant patients is associated with decreased effector CD8 cells in lung lavages: a case series

BACKGROUND

Lung transplantation is associated with a high incidence of gastroesophageal reflux disease (GERD). The presence of GERD is considered a risk factor for the subsequent development of obliterative bronchiolitis (OB), and surgical correction of GERD by gastric fundoplication (GF) may be associated with increased freedom from OB. The mechanisms underlying a protective effect from OB remain elusive. The objective of this study was to analyze the flow cytometric properties of BAL cells in patients who have undergone GF early after transplant.

METHODS

In a single-center lung transplant center, eight patients with GERD who were in the first transplant year underwent GF. Prior to and immediately following GF, BAL cells were analyzed by polychromatic flow cytometry. Spirometry was performed before and after GF.

RESULTS

GF was associated with a significant reduction in the frequency of BAL CD8 lymphocytes expressing the intracellular effector marker granzyme B, compared with the pre-GF levels. Twenty-six percent of CD8 cells were granzyme Bhi pre-GF compared with 12% of CD8 cells post-GF (range 8%-50% pre-GF, 2%-24% post-GF, P = .01). In contrast, GF was associated with a significant interval increase in the frequency of CD8 cells with an exhausted phenotype (granzyme Blo, CD127lo, PD1hi) from 12% of CD8 cells pre-GF to 24% post-GF (range 1.7%-24% pre-GF and 11%-47% post-GF, P = .05). No significant changes in spirometry were observed during the study interval.

CONCLUSIONS

Surgical correction of GF is associated with a decreased frequency of potentially injurious effector CD8 cells in the BAL of lung transplant recipients.

Induction therapy: why, when, and which agent?

The long-term outcome of paediatric transplantation has improved over the last decade with an increase in the armamentarium of immunosuppressive agents. However, the battle against the hostile immune response at the time of and after transplantation continues. Induction therapy can reduce early injury, to optimize the long-term allograft survival. The goal of induction immunosuppression in paediatric transplantation is to permit the use of lower doses of maintenance immunosuppressive agents without increased rates of acute allograft rejection and chronic allograft damage. The aim of this review is to summarize the current literature relating to the use of antibody agents for induction in paediatric solid organ transplantation.

The controversial role of surveillance bronchoscopy after lung transplantation

PURPOSE OF REVIEW

Clinically mandated transbronchial biopsy is universally regarded as the most efficient tool to establish pathology in the allograft. However, the utility of surveillance transbronchial biopsy to facilitate early detection and treatment of acute pulmonary allograft rejection is a matter of current debate. The purpose of this review is to summarize the evidence for and against the performance of surveillance bronchoscopy postlung transplantation, to discuss the risk/benefit ratio and the application of this procedure in the individual patient.

RECENT FINDINGS

Detection of silent acute rejection of the pulmonary allograft remains an important benefit of surveillance bronchoscopy although definitive evidence for a positive impact on survival or prevention of development of the bronchiolitis syndrome (BOS) is yet to be demonstrated. Perhaps the wrong target has been the focus as new evidence suggests that high grade lymphocytic bronchiolitis is the important independent risk factor for the development of BOS and death after lung transplantation. Providing effective therapies for lymphocytic bronchiolitis can be developed there is now strong support for performance of surveillance transbronchial biopsy. Most studies attest to a low risk of severe complications.

SUMMARY

Surveillance bronchoscopy is useful to detect asymptomatic acute rejection but also to determine the presence and severity of lymphocytic bronchiolitis, which should be the new target of therapeutic endeavours. It is acknowledged that the true risk/benefit ratio of surveillance bronchoscopy may differ between programs so each case deserves individual consideration.

Polymorphisms in innate immunity genes associated with development of bronchiolitis obliterans after lung transplantation

BACKGROUND

Activation of the immune system is suggested to prevent transplant tolerance and to promote the development of bronchiolitis obliterans syndrome (BOS). The innate immune system is activated by the interaction of pathogen-associated molecular patterns of microorganisms with Toll-like receptors (TLRs). Activation of innate immunity via TLRs was shown to be a barrier to the induction of transplantation tolerance after lung transplantation. We hypothesized that polymorphisms in 10 genes coding for TLR1 to TLR10 might contribute to an altered immune response and the subsequent development of BOS.

METHODS

DNA was collected from 110 lung transplant recipients. Twenty patients developed BOS. The control group comprised 422 individuals. Sixty-four single-nucleotide polymorphisms (SNPs) in 10 genes coding for TLR1 to TLR10 were genotyped.

RESULTS

The genotype distribution of TLR2 (rs1898830 and rs7656411), TLR4 (rs1927911) and TLR9 (rs352162 and rs187084) was significantly different between BOS(pos) patients and BOS(neg) patients and controls. The BOS(pos) group had significantly more patients with 3 or 4 of these risk alleles compared with the BOS(neg) and control groups.

CONCLUSIONS

Polymorphisms in TLR2, TLR4 and TLR9 that recognize bacterial and viral pathogens are associated with BOS after lung transplantation.

Acute cellular rejection is a risk factor for bronchiolitis obliterans syndrome independent of post-transplant baseline FEV1

BACKGROUND

Post-transplant baseline forced expiratory volume in 1 second (FEV(1)) constitutes a systematic bias in analyses of bronchiolitis obliterans syndrome (BOS). This retrospective study evaluates risk factors for BOS adjusting for the confounding of post-transplant baseline FEV(1).

METHODS

A multivariate survival and competing risk analysis of a large consecutive series of patients (n = 389) from a national center 1992 to 2004. Exclusion criteria were patients not surviving at least 3 months after transplantation (n = 39) and no available lung function measurements (n = 4).

RESULTS

The first maximum FEV(1) occurred at a median 183 days post-transplant. Freedom from BOS was 81%, 53%, 38% and 15%, and cumulative incidence of BOS was 18%, 43%, 57% and 77% at 1, 3, 5 and 10 years post-transplantation, respectively. Acute cellular rejection was independently associated with an increased cause-specific hazard of BOS (hazard ratio 1.4, confidence interval 1.1 to 1.8, p = 0.009). The absolute value of baseline FEV(1) was a significant confounder in all survival and competing risk analyses of BOS (p < 0.05).

CONCLUSION

Despite early diagnosis and prompt treatment, acute cellular rejection remains an independent risk factor for the development of BOS after adjusting for the confounding of post-transplant baseline FEV(1).

Fibrocytes are associated with vascular and parenchymal remodelling in patients with obliterative bronchiolitis

BACKGROUND

The aim of the present study was to explore the occurrence of fibrocytes in tissue and to investigate whether the appearance of fibrocytes may be linked to structural changes of the parenchyme and vasculature in the lungs of patients with obliterative bronchiolitis (OB) following lung or bone marrow transplantation.

METHODS

Identification of parenchyme, vasculature, and fibrocytes was done by histological methods in lung tissue from bone marrow or lung-transplanted patients with obliterative bronchiolitis, and from controls.

RESULTS

The transplanted patients had significantly higher amounts of tissue in the alveolar parenchyme (46.5 +/- 17.6%) than the controls (21.7 +/- 7.6%) (p < 0.05). The patients also had significantly increased numbers of fibrocytes identified by CXCR4/prolyl4-hydroxylase, CD45R0/prolyl4-hydroxylase, and CD34/prolyl4-hydroxylase compared to the controls (p < 0.01). There was a correlation between the number of fibrocytes and the area of alveolar parenchyma; CXCR4/prolyl 4-hydroxylase (p < 0.01), CD45R0/prolyl 4-hydroxylase (p < 0.05) and CD34/prolyl 4-hydroxylase (p < 0.05). In the pulmonary vessels, there was an increase in the endothelial layer in patients (0.31 +/- 0.13%) relative to the controls (0.037 +/- 0.02%) (p < 0.01). There was a significant correlation between the number of fibrocytes and the total area of the endothelial layer CXCR4/prolyl 4-hydroxylase (p < 0.001), CD45R0/prolyl 4-hydroxylase (p < 0.001) and CD34/prolyl 4-hydroxylase (p < 0.01). The percent areas of the lumen of the vessels were significant (p < 0.001) enlarged in the patient with OB compared to the controls. There was also a correlation between total area of the lumen and number of fibrocytes, CXCR4/prolyl 4-hydroxylase (p < 0.01), CD45R0/prolyl 4-hydroxylase (p < 0.001) and CD34/prolyl 4-hydroxylase (p < 0.01).

CONCLUSION

Our results indicate that fibrocytes are associated with pathological remodelling processes in patients with OB and that tissue fibrocytes might be a useful biomarker in these processes.

Aspergillus colonization of the lung allograft is a risk factor for bronchiolitis obliterans syndrome

Multiple infections have been linked with the development of bronchiolitis obliterans syndrome (BOS) post-lung transplantation. Lung allograft airway colonization by Aspergillus species is common among lung transplant recipients. We hypothesized that Aspergillus colonization may promote the development of BOS and may decrease survival post-lung transplantation. We reviewed all lung transplant recipients transplanted in our center between January 2000 and June 2006. Bronchoscopy was performed according to a surveillance protocol and when clinically indicated. Aspergillus colonization was defined as a positive culture from bronchoalveolar lavage or two sputum cultures positive for the same Aspergillus species, in the absence of invasive pulmonary Aspergillosis. We found that Aspergillus colonization was strongly associated with BOS and BOS related mortality in Cox regression analyses. Aspergillus colonization typically preceded the development of BOS by a median of 261 days (95% CI 87-520). Furthermore, in a multivariate Cox regression model, Aspergillus colonization was a distinct risk factor for BOS, independent of acute rejection. These data suggest a potential causative role for Aspergillus colonization in the development of BOS post-lung transplantation and raise the possibility that strategies aimed to prevent Aspergillus colonization may help delay or reduce the incidence of BOS.

Tacrolimus and azathioprine versus cyclosporine and mycophenolate mofetil after lung transplantation: a retrospective cohort study

BACKGROUND

The efficacy and safety of different combinations of immunosuppressive regimens after lung transplantation are unknown.

METHODS

We examined 120 consecutive transplant recipients between July 2001 and July 2005, of whom 37 received cyclosporine and mycophenolate mofetil (Cyc/MMF) and 83 received tacrolimus and azathioprine (Tac/Aza) as the initial immunosuppressive regimen along with an interleukin-2 antagonist induction therapy. The primary outcome was the rate of histologically confirmed acute rejection.

RESULTS

The rate of acute rejection did not vary by treatment regimen (0.42 vs 0.34 episodes per 100 person-days in Cyc/MMF and Tac/Aza groups, respectively, p = 0.22). The mean cumulative lymphocytic bronchiolitis score was greater in the Cyc/MMF group (1.8 +/- 1.9) compared with the Tac/Aza group (1.2 +/- 2.0; p = 0.03). Pulmonary function at 1 year was better in the Tac/Aza group, even when adjusted for recipient age, gender, and transplant procedure. Survival and the rate of bronchiolitis obliterans syndrome did not vary by group.

CONCLUSIONS

Outcomes after lung transplantation did not meaningfully vary between those assigned to Cyc/MMF compared with Tac/Aza combined with IL-2 inhibitor induction therapy.

Indicators for steroid response in biopsy proven acute graft rejection after lung transplantation

OBJECTIVE

Acute rejection (AR) after lung transplantation (LTx) requires prompt intervention. Most episodes respond to steroid pulse therapy. The aim of this study was to evaluate clinical indicators for non-response to steroid treatment in biopsy proven AR after the early postoperative period.

METHODS

We prospectively analysed 85 patients more than 6 months after LTx with symptomatic biopsy proven AR (>or=grade A1) from Jan. 2005 until Nov. 2007 in a single centre. In 47 patients, AR was steroid-sensitive (group 1), 38 patients did not respond to steroid pulse therapy (group 2). All AR episodes were associated with clinical symptoms. Fifty-seven (67%) were low-grade rejections (ISHLT A1).

RESULTS

Independent clinical predictors for steroid response vs. non-steroid response in biopsy proven AR were "days after transplantation" (p=0.01, adjusted hazard ratio (HR) 1.2), "decline in home spirometry slope" (p=0.03, HR 0.97), "adherence to home spirometry" (p=0.05, HR 0.98) and "serum CRP" (p=0.02, HR 0.87). Eight patients (21%) of group 2 developed BOS during the following 6 months.

CONCLUSIONS

Early detection of deterioration in graft function seems to be crucial for effective treatment of AR. Home spirometry seems to be useful in detecting early changes in graft function and surveillance protocols could be potentially helpful in predicting patients likely to demonstrate a steroid response.

Bronchiolitis obliterans in lung transplantation: the good, the bad, and the future

Lung transplantation remains the hope for many incurable pulmonary diseases, such as cystic fibrosis, pulmonary fibrosis, and chronic obstructive pulmonary disease. Remarkable progress has been made in improving outcomes, although the incidence of acute rejection remains more than 50% in the 1st year, and the 5-year graft survival is still less than 50% primarily because of the development of chronic rejection and graft dysfunction. Chronic rejection is characterized by the development of obliterative bronchiolitis in allografts and manifests as bronchiolitis obliterans syndrome in humans with no effective treatment. Previous studies support a role for alloreactive T cells in the development of bronchiolitis obliterans syndrome, but the specific mechanisms are unknown. One major stumbling block to research in the field of lung transplantation has been the lack of physiologic models to study the disease in the laboratory. We will review the current understanding of the immunology of the pathogenesis of obliterative bronchiolitis and will discuss exciting new advances from the laboratory as well as the implications for future research in lung transplantation.