Observational Study of Methotrexate in the Treatment of Bronchiolitis Obliterans Syndrome

Lymphocyte Depleting and Modulating Therapies for Chronic Lung Allograft Dysfunction

Chronic lung rejection, also called chronic lung allograft dysfunction (CLAD), remains the major hurdle limiting long-term survival after lung transplantation, and limited therapeutic options are available to slow the progressive decline in lung function. Most interventions are only temporarily effective in stabilizing the loss of or modestly improving lung function, with disease progression resuming over time in the majority of patients. Therefore, identification of effective treatments that prevent the onset or halt progression of CLAD is urgently needed. As a key effector cell in its pathophysiology, lymphocytes have been considered a therapeutic target in CLAD. The aim of this review is to evaluate the use and efficacy of lymphocyte depleting and immunomodulating therapies in progressive CLAD beyond usual maintenance immunosuppressive strategies. Modalities used include anti-thymocyte globulin, alemtuzumab, methotrexate, cyclophosphamide, total lymphoid irradiation, and extracorporeal photopheresis, and to explore possible future strategies. When considering both efficacy and risk of side effects, extracorporeal photopheresis, anti-thymocyte globulin and total lymphoid irradiation appear to offer the best treatment options currently available for progressive CLAD patients. SIGNIFICANCE STATEMENT: Effective treatments to prevent the onset and progression of chronic lung rejection after lung transplantation are still a major shortcoming. Based on existing data to date, considering both efficacy and risk of side effects, extracorporeal photopheresis, anti-thymocyte globulin, and total lymphoid irradiation are currently the most viable second-line treatment options. However, it is important to note that interpretation of most results is hampered by the lack of randomized controlled trials.

Clinical observation on the safety and efficacy of umbilical cord mesenchymal stem cells in the treatment of bronchiolitis obliterans after allogeneic haematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is caused by a pathologic and destructive response of the organism as a result of the interaction between donor immunocompetent T lymphocytes and the recipient tisular antigens1. Graft-versus-host disease is considered a serious complication of hematopoietic stem cell transplantation. The skin, oral cavity and lungs are commonly affected organs. Among these complications bronchiolitis obliterans syndrome is a serious complication, which even can be life-threatening. Therefore, this research aims to do a clinical observation on the safety and efficacy of umbilical cord mesenchymal stem cells in the treatment of bronchiolitis obliterans after allogeneic haematopoietic stem cell transplantation. Fifteen patients were included in this study, who received allogeneic hematopoietic stem cell transplantation. Among these patients, both of them were treated with azithromycin, montelukast, glucocorticoid and pirfenidone. Two of them did not receive second line anti-rejection treatment due to economic reasons, and three of them were treated with mesenchymal stem cells. These bronchiolitis obliterans syndrome-related symptoms such as shortness of breath, chest tightness and wheezing have improved. Two of them died due to bronchiolitis obliterans syndrome related complications such as respiratory failure. Two of them not only improve the symptoms but also increased the FEV1/FVC, who were treated with mesenchymal stem cells. The comprehensive treatment regimen containing imatinib and ruxolitinib is safe and effective and mesenchymal stem cell is a promising treatment option to improve the prognosis of post-HSCT BOS.

Early onset of azithromycin to prevent CLAD in lung transplantation: Promising results of a retrospective single centre experience

INTRODUCTION

Azithromycin (AZI) may be an effective immune modulator in lung transplant (LT) recipients, and can decrease chronic lung allograft dysfunction (CLAD) rates, the leading cause of mortality after the 1st year post-LT. The aim of the study is to assess the effect of AZI initiation and its timing on the incidence and severity of CLAD in LT recipients.

METHODS

Single-center retrospective study, including LT recipients from 01/01/2011 to 30/06/2020. Four groups were established: those who started AZI at the 3rd week post-LT (group A), those who received AZI later than the 3rd week post-LT and had preserved FEV1 (B), those who did not receive AZI (C) and those who started AZI due to a decline in FEV1 (D). The dosage of AZI prescribed was 250 mg three times per week. CLAD was defined and graduated according to the 2019 ISHLT criteria.

RESULTS

We included 358 LT recipients: 139 (38.83%) were in group A, 94 (26.25%) in group B, 91 (25.42%) in group C, and 34 (9.50%) in group D. Group A experienced the lowest CLAD incidence and severity at 1 (p = .01), 3 (p < .001), and 5 years post-LT, followed by Group B. Groups C and D experienced a higher incidence and severity of CLAD (p = .015). Initiation of AZI prior to FEV1 decline (Groups A and B) proved to be protective against CLAD after adjusting for differences between the treatment groups.

CONCLUSIONS

Early initiation of AZI in LT recipients could have a role in decreasing the incidence and severity of CLAD. In addition, as long as FEV1 is preserved, initiating AZI at any time could also be useful to prevent the incidence of CLAD and reduce its severity.

Pharmacotherapy of chronic lung allograft dysfunction post lung transplantation

Chronic lung allograft dysfunction (CLAD) remains the primary cause of death in lung transplant recipients (LTRs) in spite of improvements in immunosuppression management. Despite advances in knowledge regarding the pathogenesis of CLAD, treatments that are currently available are usually ineffective and delay progression of disease at best. There are currently no evidence-based guidelines for the optimal treatment of CLAD, and management varies widely across transplant centers. Additionally, there are minimal publications available to summarize data for currently available therapies and outcomes in LTRs. We identified the major domains of the medical management of CLAD and conducted a comprehensive search of PubMed and Embase databases to identify articles published from inception to December 2021 related to CLAD in LTRs. Studies published in English pertaining to the pharmacologic prevention and treatment of CLAD were included; highest priority was given to prospective, randomized, controlled trials if available. Prospective observational and retrospective controlled trials were prioritized next, followed by retrospective uncontrolled studies, case series, and finally case reports if the information was deemed to be pertinent. Reference lists of qualified publications were also reviewed to find any other publications of interest that were not found on initial search. In the absence of literature published in the aforementioned databases, additional articles were identified by reviewing abstracts presented at the International Society for Heart and Lung Transplantation and American Transplant Congress annual meetings between 2010-2021. This document serves to provide a comprehensive review of the literature and considerations for the prevention and medical management of CLAD. This article is protected by copyright. All rights reserved.

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.

Diagnostic value of ventilation/perfusion single-photon emission computed tomography/computed tomography for bronchiolitis obliterans syndrome in patients after lung transplantation

OBJECTIVE

To evaluate the diagnostic value of function volume/morphological volume ratio calculated from ventilation/perfusion single-photon emission computed tomography/computed tomography in distinguishing the lungs with bronchiolitis obliterans syndrome (BOS) from the lungs without this syndrome after lung transplantation and to assess its relationship with spirometry parameters.

MATERIALS AND METHODS

We retrospectively identified 84 consecutive lung transplant recipients and 13 donors who underwent ventilation/perfusion single-photon emission computed tomography/computed tomography. Differences in the function volume/morphological volume ratio of unilateral lungs were tested for significance between the lungs with and without BOS. Receiver operating characteristics and correlations between function volume/morphological volume ratios of bilateral lungs and forced expiratory volume in 1 s, forced vital capacity, and total lung capacity were analyzed.

RESULTS

The function volume/morphological volume ratios of ventilation and perfusion images of unilateral lungs were significantly lower in lungs with BOS (each P<0.0001). The area under the curve values of ventilation and perfusion images were 0.97 and 0.99, respectively. Significant correlations were identified between the function volume/morphological volume ratios of ventilation and perfusion images and forced expiratory volume in 1 s (r=0.54, P<0.0001 and r=0.45, P<0.0001, respectively). The function volume/morphological volume ratio of ventilation image had a significantly weak correlation with forced vital capacity.

CONCLUSION

The function volume/morphological volume ratio enables a semiquantitative assessment of ventilation and perfusion lung functions and is useful for diagnosing BOS after lung transplantation.