Conservation of small-airway function by tacrolimus/cyclosporine conversion in the management of bronchiolitis obliterans following lung transplantation

Management of chronic rejection after lung transplantation

Outcomes after lung transplantation are limited by chronic lung allograft dysfunction (CLAD). The incidence of CLAD is high, and its clinical course tends to be progressive over time, culminating in graft failure and death. Indeed, CLAD is the leading cause of death beyond the first year after lung transplantation. Therapy for CLAD has been limited by a lack of high-quality studies to guide management. In this review, we will discuss the diagnosis of CLAD in light of the recent changes to definitions and will discuss the current clinical evidence available for treatment. Recently, the diagnosis of CLAD has been subdivided into bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). The current evidence for treatment of CLAD mainly revolves around treatment of BOS with more limited data existing for RAS. The best supported treatment to date for CLAD is the macrolide antibiotic azithromycin which has been associated with a small improvement in lung function in a minority of patients. Other therapies that have more limited data include switching immunosuppression from cyclosporine to tacrolimus, fundoplication for gastroesophageal reflux, montelukast, extracorporeal photopheresis (ECP), aerosolized cyclosporine, cytolytic anti-lymphocyte therapies, total lymphoid irradiation (TLI) and the antifibrotic agent pirfenidone. Most of these treatments are supported by case series and observational studies. Finally, we will discuss the role of retransplantation for CLAD.

An update on current treatment strategies for managing bronchiolitis obliterans syndrome after lung transplantation

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS), a subtype of chronic lung allograft dysfunction, is quite common, with up to half of all lung recipients developing BOS within 5 years of transplantation. Preventive efforts are aimed at alleviating known risk factors of BOS development, while the primary goal of treatment is to delay the irreversible, fibrotic airway changes, and progressive loss of lung function.

AREAS COVERED

This narrative review will briefly discuss the updated definition, clinical presentation, pathogenesis, risk factors, and survival after BOS while paying particular attention to the salient evidence for optimal preventive strategies and treatments based on investigations in the modern era.

EXPERT OPINION

Future translational research focused on further characterizing the complex interplay between immune and nonimmune mechanisms mediating chronic lung rejection is the first step toward mitigating risk of allograft injury, improving early disease detection with noninvasive biomarkers, and ultimately, developing an effective, targeted therapy that can extend the life of the lung allograft.

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.

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.

Pediatric bronchoalveolar lavage: practical considerations and future prospects

Despite the utilization of bronchoalveolar lavage (BAL) in children since the early 1970s, several challenges remain once the procedure is complete. These include little documentation on normal controls, the limitations due to the size of the patient, and uniform processes for assessment. It was not until 1995 that a taskforce on pediatric BAL was formed by the European Respiratory Society, and to our knowledge, they remain the only committee evaluating the process [1]. We examined our procedures and reviewed the literature in an attempt to document the most fruitful practices that would allow improved data comparison and introduce possible investigations.

Conversion From Cyclosporine to Tacrolimus Stabilizes the Course of Lung Function in Lung Transplant Recipients With Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans syndrome (BOS) continues to be the main factor limiting the long-term survival of lung transplant recipients. The objective of this study was to prospectively assess the impact of conversion from cyclosporine (CsA) to tacrolimus on lung function in patients who developed BOS while receiving CsA-based immunosuppressive therapy. A total of 79 patients with BOS were included in the study. Sixty percent of patients had stage II or III BOS according to the International Society for Heart and Lung Transplantation criteria. Mean time from transplantation was 30.4 +/- 21.9 months and all patients were on CsA therapy at enrollment in the study, with mean trough levels of 232.75 +/- 98.26 ng/mL. After conversion, tacrolimus trough levels were 11.0 +/- 3.6 ng/mL at 3 months and 9.0 +/- 3.4 ng/mL at 12 months. Sixteen deaths occurred during the first year postconversion, 56% of which were due to respiratory failure. Comparison of forced expiratory volume in 1 second (FEV(1)) preconversion versus postconversion showed a change in the slope of the FEV(1)-time curve. The slope of the preconversion curve was -0.44 versus a zero slope, whereas the slope of the postconversion curve was 0.005, with a statistically significant difference between both slopes. This change in slopes, which was also seen in FEV(1%), suggests that lung function loss closed after conversion from CsA to tacrolimus supporting this therapeutic strategy in lung transplant recipients with BOS treated with CsA.

Are heart-lung transplant recipients protected from developing bronchiolitis obliterans syndrome?

BACKGROUND

Heart-lung transplant recipients, when compared with heart transplant recipients, are relatively spared from allograft coronary artery disease. This study was undertaken to investigate whether heart-lung transplant recipients are also spared from experiencing bronchiolitis obliterans syndrome (BOS) when compared with double-lung transplant recipients. In addition, the risk factors for developing BOS after lung transplantation were analyzed.

METHODS

Heart-lung and bilateral sequential double-lung transplant recipients were reviewed retrospectively from 1990 to 2000 using the Stanford Transplant Database. The heart-lung transplant group consisted of 77 heart-lung transplant recipients and the double-lung transplant group consisted of 51 double-lung transplant recipients. The rates of BOS, survival, acute rejection, and cytomegalovirus infection at 1, 3, and 5 years were measured.

RESULTS

There were no significant differences in patient demographics between the two groups. Rates of survival and acute rejection were similar in the two transplant groups. The incidence of cytomegalovirus infection was significantly higher in heart-lung transplant recipients. Freedom from BOS was similar in the two transplant groups. Risk factors for the development of BOS in the heart-lung and double-lung transplant recipients included male donor, younger recipient age, a diagnosis other than cystic fibrosis, nonuse of cardiopulmonary bypass, and the use of OKT3 induction therapy.

CONCLUSIONS

Heart-lung transplant recipients exhibit BOS at a rate similar to double-lung transplant recipients. The immunoprotective effect the lung allograft presumably provides the heart is not reciprocated by the heart in preventing the development of BOS.

Airway cellular response to two different immunosuppressive regimens in lung transplant recipients

A number of new immunosuppressive drugs have become available in transplant medicine. We investigated the effects of two different immunosuppressive protocols on bronchoalveolar lavage fluid cellular characteristics in 34 lung transplant recipients who were treated with anti-thymocyte globulin induction therapy, cyclosporine, azathioprine (AZA), and prednisolone (regimen I), compared with 17 recipients receiving basiliximab induction, tacrolimus, AZA, and prednisolone (regimen II). We performed bronchoalveolar lavages between 15 and 40 d post-transplantation, in stable clinical condition and no acute rejection, cytomegalovirus, and/or respiratory tract infection. The regimen II treatment was associated with a significantly lower percentage lavage fluid lymphocytes than with regimen I. The CD4/CD8 ratio was significantly higher with regimen II than with regimen I: 1.56 (range 0.41-2.16) and 0.33 (0.04-0.95) respectively; p < 0.001, mainly because of a lower percentage CD8(+) cells with regimen II: 25% (12-51) vs. regimen I: 60% (34-77); p < 0.001. The percentage CD4(+) CD25(+) cells appeared lower with regimen II: 21% (10-88) vs. regimen I: 50% (0-87); p = 0.04. Overall survival was similar between the groups, whereas a beneficial trend in freedom of bronchiolitis obliterans syndrome was observed with regimen II. Airway lymphocyte subtypes are affected by the immunosuppressive protocol used. This observation should be taken into account when studying transplant recipients, and may contribute to our understanding of alloreactive airway disease.

Bronchiolitis Obliterans Syndrome

Post-transplantation bronchiolitis obliterans syndrome (BOS) is a clinicopathological syndrome characterised histologically by obliterative bronchiolitis (OB) and physiologically by airflow limitation. It affects long-term survival with no consistently effective treatment strategy.An updated review of risk factors for OB/BOS, and approaches to prevention and treatment was performed through a systematic review of relevant studies between January 1990 and February 2005. The initial search identified 853 publications, with 56 articles reviewed after exclusions. Early acute rejection is the most significant risk factor, with late rejection (> or =3 months) also significant. Lymphocytic bronchitis/bronchiolitis is relevant, with later onset associated with greater risk. Viral infections are identified as significant risk factors. Human leukocyte antigen matching and OB/BOS development is a weaker association, but is stronger with acute rejection. Recipient and donor characteristics have a minor role. There is limited evidence that altering immunosuppression is effective in reducing the rate of decline in lung function. BOS reflects an allo-immunological injury, possibly triggered by cytomegalovirus and respiratory viral infections, or noninfectious injury. Immunological susceptibility may be reflected by more frequent acute rejection episodes. Preventative and therapeutic modifications in immunosuppression remain important. Identifying markers of immunological susceptibility and, hence, risk stratification requires further research.

Bronchoalveolar lavage fluid characteristics in acute and chronic lung transplant rejection

BACKGROUND

The detection of graft rejection by bronchoalveolar lavage remains controversial.

METHODS

To assess the value of bronchoalveolar lavage fluid in acute and chronic rejection after lung transplantation we analyzed bronchoalveolar lavage fluid cellular differential characteristics, lymphocyte sub-types and interleukin-6 (IL-6) and interleukin-8 (IL-8) cytokine levels in patients with exclusively either acute rejection (n = 37) or bronchiolitis obliterans (BO; n = 48). Both groups were compared with a control group of lung transplantation patients without rejection or infection, matched for the time the lavage was performed after lung transplantation.

RESULTS

The bronchiolitis obliterans group showed marked neutrophilia, high IL-8 and higher CD4(+)CD25(+) and CD8(+)CD45(+) bronchoalveolar lavage fluid levels when compared with their stable controls. When using a cut-off point of >3% neutrophils in the lavage, the sensitivity for BO is 87.0%, the specificity 77.6%. The sensitivity of IL-8 for BO when using a cut-off point of >71.4 pg/ml is 74.5%, the specificity 83.3%. Bronchoalveolar lavage fluid in acute rejection was characterized by marked lymphocytosis, but showed no difference when compared with stable controls in any of the lymphocyte sub-types studied. When using a cut-off point of <==1% lymphocytes in the lavage, the sensitivity for acute rejection (AR) is 40.4%, the specificity 95.6%. The marked neutrophilia, high IL-8 cytokine level and more activated lymphocyte population in bronchiolitis obliterans may indicate ongoing local allograft rejection.

CONCLUSIONS

In the present study we were not able to show any difference in lymphocyte sub-types when comparing acute rejection and control subjects. Cellular and soluble parameters in bronchoalveolar lavage fluid appear useful for diagnosing bronchiolitis obliterans.

Feasibility of sputum induction in lung transplant recipients

Sputum induction (SI) is nowadays being applied as a non-invasive and safe method to investigate airway inflammation in pulmonary diseases. We investigated the feasibility of SI after lung transplantation (LTX), and compared sputum and bronchoalveolar lavage (BAL) cellular characteristics and interleukin-8 (IL-8) levels. Results were also compared with 11 healthy subjects. SI as performed between 26 and 1947 d after LTX in 19 recipients, was successful in 16 of 22 attempts (73%). Six patients failed to produce sputum after induction, mostly just post-LTX and with having a lower forced expiratory volume in 1 s (FEV1). The success rate in clinically stable patients after the first month post-LTX was 93%. Side-effects were absent. Sputum recovery, viability and squamous cell contamination were comparable between LTX patients and healthy subjects. In the LTX group, total cell counts, neutrophil percentages and IL-8 levels were much higher in SI than BAL (1.6 x 10(6)/mL, 65.5% and 54.2 ng/mL vs. 0.1 x 10(6)/mL, 3.0% and 0.01 ng/mL; p < 0.001). Although LTX-neutrophil percentages in SI and BAL correlated properly (rho=0.72, p=0.04), both techniques are not interchangeable. We conclude that sputum induction is feasible, well tolerated, and without major side-effects in stable patients after the first month post-LTX. Induced sputum may be a useful tool to study inflammatory changes of the airways after LTX, and because of the large quantity of neutrophils sampled, especially for further studies on the pathogenesis of bronchiolitis obliterans.

An update on clinical outcomes in heart and lung transplantation

Much progress has been made in heart and lung transplantation over recent decades. The immune mechanisms that result in allograft rejection are now better understood, and the development of immunosuppressant therapies has decreased recipient mortality among transplant recipients. During the 1980s, immunosuppressant therapy primarily involved the use of corticosteroids and cyclosporine. However, while survival rates increased among transplant recipients, many patients experienced primary graft failures, acute and chronic rejection, as well as death. Until the introduction of tacrolimus in the early 1990s, all patients received the same immunosuppressant regimen, regardless of its effectiveness. Tacrolimus therapy has contributed much to the success rates of both heart and lung transplantation, and by 2001, it had become the preeminent immunosuppressant agent used in lung transplantation.

Interferon gamma-1b as therapy for idiopathic pulmonary fibrosis. An intrapatient analysis

BACKGROUND

The only proven therapeutic option for idiopathic pulmonary fibrosis (IPF) is lung transplantation. It is biologically plausible that interferon gamma-1b (G-IFN) may halt or even reverse the disease process and therefore prove to be an effective medical therapy. We report our results using this medication in a cohort of patients with a wide range of severity of IPF.

OBJECTIVES

To determine the impact of G-IFN therapy on the progression of disease in patients with IPF.

METHODS

We performed a retrospective analysis of patients' pulmonary function tests (PFTs), specifically the forced vital capacity (FVC) and the single breath diffusing capacity for carbon dioxide (DLCO). Comparisons of these parameters prior to and after the implementation of therapy were made by generating regression slopes by least-squares equations.

RESULTS

Twenty-two patients qualified for the analysis. For the FVC, comparison of pre- and post-therapy best-fit regression lines demonstrated a significant difference in favor of G-IFN (p<0.015). For the DLCO, a significant difference in favor of gamma interferon therapy was detected in the advanced group (p<0.03). Seventy percent of the patients showed either stabilization or regression of disease in both their FVCs and their DLCO.

CONCLUSION

G-IFN appears to be an effective new therapy for patients with IPF. Salutary effects on the rate of change in the FVC and DLCO were most apparent in patients with advanced disease. With slowing or reversal in loss of lung function, G-IFN may improve longevity and may have utility as a bridge to lung transplantation in those patients who are appropriate candidates.

International experience with conversion from cyclosporine to tacrolimus for acute and chronic lung allograft rejection

OBJECTIVE

A retrospective study involving 13 institutions was performed to assess the efficacy of conversion from cyclosporine (INN: ciclosporin) to tacrolimus.

METHODS

Data from 244 patients were analyzed. Indications for conversion were recurrent-ongoing rejection (n = 110) and stage 1 to 3 bronchiolitis obliterans syndrome (n = 134).

RESULTS

The incidence of acute rejection decreased significantly within 3 months after versus before the switch from cyclosporine to tacrolimus (P <.01). For patients with recurrent-ongoing rejection, the forced expiratory volume in 1 second decreased by 1.96% of predicted value per month (P =.08 vs zero slope) before and increased by 0.34% of predicted value per month (P =.32 vs zero slope) after conversion (P <.06). For patients with stage 1 to 3 bronchiolitis obliterans syndrome, a significant reduction of rejection episodes was observed (P <.01). In single transplant recipients a decrease of the forced expiratory volume in 1 second averaged 2.25% of predicted value per month (P <.01 vs zero slope) before and 0.29% of predicted value per month after conversion. Corresponding values for bilateral transplant recipients were 3.7% of predicted value per month (P <.01 vs zero slope) and 0.9% of predicted value per month (P = 0.04 vs zero slope), respectively. No significant difference in the incidence of infections within 3 months before and after conversion was observed.

CONCLUSIONS

Conversion from cyclosporine to tacrolimus after lung transplantation is associated with reversal of recurrent-ongoing rejection. Conversion for bronchiolitis obliterans syndrome allows short-term stabilization of lung function in most patients.

Time-related changes in pulmonary function after conversion to tacrolimus in bronchiolitis obliterans syndrome

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a leading cause of morbidity and mortality after lung and heart-lung transplantation. Present treatment is directed at the augmentation of pharmacologic immunosuppression.

METHODS

This study examines the effect of substituting cyclosporine with tacrolimus on the forced expiratory volume in 1 second (FEV(1)) and on the forced expiratory flow between 25% and 75% of vital capacity (FEF(25%-75%)) in 32 patients who developed BOS. The proportional rates of decline of FEV(1) and FEF(25%-75%) before and after treatment with tacrolimus were calculated. The actuarial survival of responders and non-responders to tacrolimus was compared. Pre-operative and post-operative factors were investigated to determine any difference between the 2 groups.

RESULTS

There were significant reductions in the rates of decline of FEV(1) and FEF(25%-75%) when the rates in the 3 months before conversion to tacrolimus were compared with subsequent rates at 0 to 3 months, 3 to 6 months, 6 to 9 months and 9 to 12 months after conversion. The rates of decline of FEV(1) and FEF(25%-75%) in the 3 months before conversion were 0.11 liters/month and 0.13 liters/s per month, respectively. This compares with the rates of decline for FEV(1) and FEF(25%-75%) for the 3 months after conversion to tacrolimus of 0.04 liters/month (p = 0.023) and 0.04 liters/s per month (p = 0.022), respectively. The actuarial survival at 1 year from the time of conversion to tacrolimus for the responder sub-group and the non-responder sub-group were 89.2% and 75%, respectively, and at 4 years after conversion were 61.3% and 56.3%, respectively (p = 0.92).

CONCLUSIONS

Tacrolimus rescue therapy is effective at stabilizing lung function in patients with BOS, and this effect is apparent up to 12 months after conversion from cyclosporine.

Longitudinal profile of bronchoalveolar lavage cell characteristics in patients with a good outcome after lung transplantation

Bronchoalveolar lavage fluid (BALF) analysis is used in patients after lung transplantation (LTX) to obtain more insight into pathological conditions such as acute and chronic allograft rejection. Information on the normal course of BALF cell characteristics in patients with "good outcome" after LTX is limited. Therefore we analyzed 169 BALF samples from 63 well-defined "good outcome" patients after LTX (no acute or chronic transplant dysfunction, bacterial, fungal, or viral infections at the time of BAL). Total cell count decreased from the first months: median (range) 234 x 10(3) (70-610) cells/ml to 103 x 10(3) (10-840) cells/ml during the second year posttransplantation (p < 0.001). Cell differential counts did not change during the 2-yr study period. The CD4/CD8 ratio increased significantly from 0.32 (0.11-0.46) just posttransplantation to 0.62 (0.16-4.27) the second year after LTX. This increasing ratio was mainly due to a sharp decreasing CD8(+) cell count. Thus, characteristics of BAL cellular patterns in patients with good outcomes after LTX show important changes over time. We have defined control values for the BALF cellular profile in patients without pathological airway conditions after LTX. We propose to use these control values as a tool for diagnosing patients with pulmonary complications after LTX and for the follow-up of treatment regimens.