Gastroesophageal Reflux Disease and Idiopathic Lung Fibrosis. From Heartburn to Lung Transplant, and Beyond.

Idiopathic pulmonary fibrosis (IPF) and gastroesophageal reflux disease (GERD) are undoubtedly related. Even though it is not clear yet which one is the primary disease, they certainly interact increasing each other's severity. Symptoms are unreliable to diagnose GERD in patients with IPF, and objective evaluation with pH monitoring and/or bronchoalveolar lavage analysis is mandatory. Pharmacological treatment with proton pump inhibitors (PPIs) may bring control of IPF in few patients, but PPIs do not control reflux but just change the pH of the gastric refluxate. Surgical therapy based on a fundoplication is safe and effective as it controls any type of reflux, independently from the pH of the gastric refluxate. In patients waiting for lung transplantation (if they can tolerate a laparoscopic operation under general anesthesia), a fundoplication before the operation might block the progression of IPF, while after transplantation it might prevent rejection by preventing the bronchiolitis obliterans syndrome.

PLK1 Inhibition alleviates transplant-associated obliterative bronchiolitis by suppressing myofibroblast differentiation.

Chronic allograft dysfunction (CAD) resulting from fibrosis is the major limiting factor for long-term survival of lung transplant patients. Myofibroblasts promote fibrosis in multiple organs, including the lungs. In this study, we identified PLK1 as a promoter of myofibroblast differentiation and investigated the mechanism by which its inhibition alleviates transplant-associated obliterative bronchiolitis (OB) during CAD. High-throughput bioinformatic analyses and experiments using the murine heterotopic tracheal transplantation model revealed that PLK1 is upregulated in grafts undergoing CAD as compared with controls, and that inhibiting PLK1 alleviates OB in vivo. Inhibition of PLK1 in vitro reduced expression of the specific myofibroblast differentiation marker α-smooth muscle actin (α-SMA) and decreased phosphorylation of both MEK and ERK. Importantly, we observed a similar phenomenon in human primary fibroblasts. Our results thus highlight PLK1 as a promising therapeutic target for alleviating transplant-associated OB through suppression of TGF-ß1-mediated myofibroblast differentiation.

Fundoplication to preserve allograft function after lung transplant: Systematic review and meta-analysis.

BACKGROUND: ARS has been adopted in select patients with lung transplant for the past 2 decades in many centers. Outcomes have been reported sporadically. No pooled analysis of retrospective series has been performed. OBJECTIVE: This review and pooled analysis sought to demonstrate objective evidence of improved graft function in lung transplant patients undergoing antireflux surgery (ARS). METHODS: In accordance with Meta-analyses of Observational Studies in Epidemiology guidelines, a search of PubMed Central, Medline, Google Scholar, and Cochrane Library databases was performed. Articles documenting spirometry data pre- and post-ARS were reviewed and a random-effects model meta-analysis was performed on forced expiratory volume in 1 second (FEV1) values and the rate of change of FEV1. RESULTS: Six articles were included in the meta-analysis. Regarding FEV1 before and after ARS, we observed a small increase in FEV1 values in studies reporting raw values (2.02 ± 0.89 L/1 sec vs 2.14 ± 0.77 L/1 sec; n = 154) and % of predicted (77.1% ± 22.1% vs 81.2% ± 26.95%; n = 45), with a small pooled Cohen d effect size of 0.159 (P = .114). When considering the rate of change of FEV1 we observed a significant difference in pre-ARS compared with post-ARS (-2.12 ± 2.76 mL/day vs +0.05 ± 1.19 mL/day; n = 103). There was a pooled effect size of 1.702 (P = .013), a large effect of ARS on the rate of change of FEV1 values. CONCLUSIONS: This meta-analysis of retrospective observational studies demonstrates that ARS might benefit patients with declining FEV1, by examining the rate of change of FEV1 during the pre- and postoperative periods.

Azithromycin Partially Mitigates Dysregulated Repair of Lung Allograft Small Airway Epithelium.

BACKGROUND: Dysregulated airway epithelial repair following injury is a proposed mechanism driving posttransplant bronchiolitis obliterans (BO), and its clinical correlate bronchiolitis obliterans syndrome (BOS). This study compared gene and cellular characteristics of injury and repair in large (LAEC) and small (SAEC) airway epithelial cells of transplant patients. METHODS: Subjects were recruited at the time of routine bronchoscopy posttransplantation and included patients with and without BOS. Airway epithelial cells were obtained from bronchial and bronchiolar brushing performed under radiological guidance from these patients. In addition, bronchial brushings were also obtained from healthy control subjects comprising of adolescents admitted for elective surgery for nonrespiratory-related conditions. Primary cultures were established, monolayers wounded, and repair assessed (±) azithromycin (1 µg/mL). In addition, proliferative capacity as well as markers of injury and dysregulated repair were also assessed. RESULTS: SAEC had a significantly dysregulated repair process postinjury, despite having a higher proliferative capacity than large airway epithelial cells. Addition of azithromycin significantly induced repair in these cells; however, full restitution was not achieved. Expression of several genes associated with epithelial barrier repair (matrix metalloproteinase 7, matrix metalloproteinase 3, the integrins ß6 and ß8, and ß-catenin) were significantly different in epithelial cells obtained from patients with BOS compared to transplant patients without BOS and controls, suggesting an intrinsic defect. CONCLUSIONS: Chronic airway injury and dysregulated repair programs are evident in airway epithelium obtained from patients with BOS, particularly with SAEC. We also show that azithromycin partially mitigates this pathology.

Hydrogen water alleviates obliterative airway disease in mice.

OBJECTIVE: Bronchiolitis obliterans syndrome arising from chronic airway inflammation is a leading cause of death following lung transplantation. Several studies have suggested that inhaled hydrogen can protect lung grafts from ischemia-reperfusion injury via anti-inflammatory and -oxidative mechanisms. We investigated whether molecular hydrogen-saturated water can preserve lung allograft function in a heterotopic tracheal allograft mouse model of obliterative airway disease METHODS: Obliterative airway disease was induced by heterotopically transplanting tracheal allografts from BALB/c donor mice into C57BL/6 recipient mice, which were subsequently administered hydrogen water (10 ppm) or tap water (control group) (n = 6 each) daily without any immunosuppressive treatment. Histological and immunohistochemical analyses were performed on days 7, 14, and 21. RESULTS: Hydrogen water decreased airway occlusion on day 14. No significant histological differences were observed on days 7 or 21. The cluster of differentiation 4/cluster of differentiation 3 ratio in tracheal allografts on day 14 was higher in the hydrogen water group than in control mice. Enzyme-linked immunosorbent assay performed on day 7 revealed that hydrogen water reduced the level of the pro-inflammatory cytokine interleukin-6 and increased that of forkhead box P3 transcription factor, suggesting an enhancement of regulatory T cell activity. CONCLUSIONS: Hydrogen water suppressed the development of mid-term obliterative airway disease in a mouse tracheal allograft model via anti-oxidant and -inflammatory mechanisms and through the activation of Tregs. Thus, hydrogen water is a potential treatment strategy for BOS that can improve the outcome of lung transplant patients.

Mitigation of Primary Graft Dysfunction in Lung Transplantation: Current Understanding and Hopes for the Future.

Primary graft dysfunction (PGD) is a form of acute lung injury that develops within the first 72 hours after lung transplantation. The overall incidence of PGD is estimated to be around 30%, and the 30-day mortality for grade 3 PGD around 36%. PGD is also associated with the development of bronchiolitis obliterans syndrome, a specific form of chronic lung allograft dysfunction. In this article, we will discuss perioperative strategies for PGD prevention as well as possible future avenues for prevention and treatment.

Adenovirus: de la neumonía a la bronquiolitis obliterante / Adenovirus: from pneumonia to obliteran bronchiolitis

Post-infectious bronchiolitis obliterans (BOPI) is a chronic obstructive disease, resulting from an acute injury and an abnormal repair process, with diffuse pulmonary fibrosis and peribronchiolar fibrosis, which cause chronic respiratory failure with prolonged oxygen dependence. The most common cause of this disease is severe bronchiolitis / pneumonia due to adenovirus (ADV), mainly in group B, before 2 years of age. In its pathogenesis are factors of the host and the characteristics of the virus that has mechanisms to prevent immunity and cause a chronic infection with great inflammatory response. This involves numerous cells (mainly lymphocytes) and cytokines that are produced by a chronic infection by ADV, which maintains a prolonged inflammatory process, determining different degrees of lung damage. In this article we will discuss the mechanisms by which this damage occurs.

La bronquiolitis obliterante postinfecciosa (BOPI) es una enfermedad obstructiva crónica, resultante de una injuria aguda y un proceso de reparación anómalo, con fibrosis pulmonar y peribronquiolar difusa, que causan insuficiencia respiratoria crónica con dependencia de oxigeno prolongada. La causa más frecuente de esta enfermedad es una bronquiolitis/neumonía grave por adenovirus (ADV), principalmente del grupo B, antes de los 2 años de vida. En su patogenia intervienen factores del huésped y las características del virus que tiene mecanismos para evitar la inmunidad y provocar una infección crónica con gran respuesta inflamatoria. En esta participan numerosas células (principalmente linfocitos) y citoquinas que se producen por una infección crónica por ADV, lo que mantiene un proceso inflamatorio prolongado, determinando distintos grados de daño pulmonar. En este artículo abordaremos los mecanismos por los cuales se produce este daño.

Changes in Immunosuppressive Treatment of Chronic Graft-versus-Host Disease: Comparison of 2 Surveys within Allogeneic Hematopoietic Stem Cell Transplant Centers in Germany, Austria, and Switzerland.

Chronic graft-versus-host disease (cGVHD) remains the leading cause of late morbidity and mortality. Despite the growing number of treatment options in cGVHD, evidence remains sparse. The German-Austrian-Swiss GVHD Consortium performed a survey on clinical practice in treatment of cGVHD among transplant centers in Germany, Austria, and Switzerland in 2009 and 2018 and compared the results. The survey performed in 2009 contained 20 questions on first-line treatment and related issues and 4 questions on second-line scenarios followed by a survey on all systemic and topic treatment options known and applied, with 31 of 36 transplant centers (86%) responding. The survey in 2018 repeated 7 questions on first-line treatment and 3 questions on second-line scenarios followed by an updated survey on all current systemic treatment options known and applied, with 29 of 66 centers (43%) responding. In summary, the results show a large overlap of first-line treatment practice between centers and the 2 surveys because of a lack of new data that changes practice, except significant heterogeneity of treatment of cGVHD progressive onset type, which can be explained by the lack of trials focusing on this high-risk entity. In contrast, treatment options applied to second-line therapy vary considerably, with new agents like ibrutinib and ruxolitinib entering clinical practice. Moreover, treatment of bronchiolitis obliterans syndrome demonstrates heterogeneity in applied therapeutic options and sequence because of a lack of controlled data and different conclusions from already existing evidence. In summary, the survey results demonstrate an increasing number of treatment options applied to cGVHD accompanied by a significant heterogeneity in second-line treatment and underline the urgent need for clinical trials and registry analyses on rare entities with high mortality like progressive onset type and lung involvement of cGVHD.

Association between chronic bacterial airway infection and prognosis of bronchiolitis obliterans syndrome after hematopoietic cell transplantation.

Bronchiolitis obliterans syndrome (BOS) is a rare pulmonary complication of hematopoietic stem cell transplantation (HSCT) with high mortality. Chronic bacterial airway infection (CAI) causes exacerbation and progression of several airway diseases, and bacterial airway colonization was shown to be associated with BOS after lung transplantation.We assessed the association between CAI and clinical course in patients with BOS after HSCT. This retrospective study included 910 patients undergoing allogeneic HSCT between 2005 and 2013 at our institution. BOS diagnosis was reevaluated according to the 2014 US National Institutes of Health criteria. Sputum and bronchial lavage culture results, pulmonary function, and survival were compared between patients with and without CAI.Median follow-up was 974.5 (261.5-2748.5) days. BOS was diagnosed in 27 (3.0%) patients, including 18 males. Median age at BOS diagnosis was 45 (40.5-58) years. Nine patients had ≥2 positive sputum cultures for bacteria or one positive bronchial lavage culture for nontuberculous mycobacteria (CAI+), whereas 9 patients had negative sputum/bronchial lavage culture or only one positive sputum culture (CAI-). Median change in forced expiratory volume in 1 s within 6 months after BOS diagnosis and overall survival were significantly worse in CAI+ patients than in CAI- patients (-250 vs +260 mL, P = .002, and 1340 days vs not reached, P = .04, respectively). No other factors including patient demographics or transplant protocol affected prognosis. There were no differences in clinical characteristics of patients with and without CAI, except for the time from transplantation to BOS diagnosis (214 vs 768 days for CAI+ and CAI-, respectively; P = .02).CAI was associated with worse outcomes in patients with BOS after HSCT. Further prospective studies should assess the association between the airway microbiome and changes in pulmonary function after HSCT to improve prognosis.

BOS is associated with decreased HDAC2 from steroid resistant lymphocytes in the small airways.

Immunosuppression therapies including corticosteroids fail to prevent bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways, following lung transplantation. We reported increases in steroid-resistant proinflammatory lymphocytes and their loss of histone deacetylase 2 (HDAC2), an important mediator of steroid action, in the blood of stable lung transplant recipients. We noted similar increases in the steroid-resistant lymphocytes in both the blood and small airways in BOS compared with the large airways. We hypothesized that these small airway cells would also exhibit a loss of HDAC2, and that these changes could be reversed by treatment with theophylline (HDAC2 activator). Blood, bronchoalveolar lavage and large and small airway brushings were collected from lung transplant patients with BOS (n = 12) or stable lung function (n = 18) and healthy aged-matched controls (n = 13). Intracellular proinflammatory cytokines [interferon (IFN-γ) and tumour necrosis factor (TNF)-α and HDAC2 were measured in CD8+ T, natural killer (NK) T-like and NK cells from cultured small airway brushings ± 5 mg/l theophylline ± 1 µM prednisolone using flow cytometry. Increased small airway CD8 T, NK T-like and NK cells were identified in BOS versus stable transplant and controls. In BOS, these cells exhibited increased IFN-γ/TNF-α and a loss of HDAC2. HDAC2 expression by small airway CD8+ T cells correlated with forced expiratory volume in 1 s (FEV1 ) (R = 0·880, P = 0·031). Theophylline and prednisolone synergistically up-regulated HDAC2 in CD8+ T cells. BOS is associated with loss of HDAC2 from steroid-resistant proinflammatory CD8+ T, NK T-like and NK cells in the small airways. Therapeutically increasing HDAC2 in these lymphocytes may reduce steroid resistance and improve graft survival.

Double lung, unlike single lung transplantation might provide a protective effect on mortality and bronchiolitis obliterans syndrome.

BACKGROUND: Survival after lung transplantation (LTx) is often limited by bronchiolitis obliterans syndrome (BOS). METHOD: Survey of 278 recipients who underwent LTx. The endpoint used was BOS (BOS grade ≥ 2), death or Re-lung transplantation (Re-LTx) assessed by competing risk regression analyses. RESULTS: The incidence of BOS grade ≥ 2 among double LTx (DLTx) recipients was 16 ± 3% at 5 years, 30 ± 4% at 10 years, and 37 ± 5% at 20 years, compared to single LTx (SLTx) recipients whose corresponding incidence of BOS grade ≥ 2 was 11 ± 3%, 20 ± 4%, and 24 ± 5% at 5, 10, and 20 years, respectively (p > 0. 05). The incidence of BOS grade ≥ 2 by major indications ranked in descending order: other, PF, CF, COPD, PH and AAT1 (p < 0. 05). The mortality rate by major indication ranked in descending order: COPD, PH, AAT1, PF, Other and CF (p < 0. 05). CONCLUSION: No differences were seen in the incidence of BOS grade ≥ 2 regarding type of transplant, however, DLTx recipients showed a better chance of survival despite developing BOS compared to SLTx recipients. The highest incidence of BOS was seen among CF, PF, COPD, PH, and AAT1 recipients in descending order, however, CF and PF recipients showed a better chance of survival despite developing BOS compared to COPD, PH, and AAT1 recipients.

Effect of Azithromycin on Airflow Decline-Free Survival After Allogeneic Hematopoietic Stem Cell Transplant: The ALLOZITHRO Randomized Clinical Trial.

Importance: Bronchiolitis obliterans syndrome has been associated with increased morbidity and mortality after allogeneic hematopoietic stem cell transplant (HSCT). Previous studies have suggested that azithromycin may reduce the incidence of post-lung transplant bronchiolitis obliterans syndrome. Objective: To evaluate if the early administration of azithromycin can improve airflow decline-free survival after allogeneic HSCT. Design, Setting, and Participants: The ALLOZITHRO parallel-group trial conducted in 19 French academic transplant centers and involving participants who were at least 16 years old, had undergone allogeneic HSCT for a hematological malignancy, and had available pretransplant pulmonary function test results. Enrollment was from February 2014 to August 2015 with follow-up through April 26, 2017. Interventions: Patients were randomly assigned to receive 3 times a week either 250 mg of azithromycin (n = 243) or placebo (n = 237) for 2 years, starting at the time of the conditioning regimen. Main Outcomes and Measures: The primary efficacy end point was airflow decline-free survival at 2 years after randomization. Main secondary end points were overall survival and bronchiolitis obliterans syndrome at 2 years. Results: Thirteen months after enrollment, the independent data and safety monitoring board detected an unanticipated imbalance across blinded groups in the number of hematological relapses, and the treatment was stopped December 26, 2016. Among 480 randomized participants, 465 (97%) were included in the modified intention-to-treat analysis (mean age, 52 [SD, 14] years; 75 women [35%]). At the time of data cutoff, 104 patients (22%; 54 azithromycin vs 50 placebo) had experienced an airflow decline; 138 patients (30%) died (78 azithromycin vs 60 placebo). Two-year airflow decline-free survival was 32.8% (95% CI, 25.9%-41.7%) with azithromycin and 41.3% (95% CI, 34.1%-50.1%) with placebo (unadjusted hazard ratio [HR], 1.3; 95% CI, 1.02-1.70; P = .03). Of the 22 patients (5%) who experienced bronchiolitis obliterans syndrome, 15 (6%) were in the azithromycin group and 7 (3%) in the placebo group (P = .08). The azithromycin group had increased mortality, with a 2-year survival of 56.6% (95% CI, 50.2%-63.7%) vs 70.1% (95% CI, 64.2%-76.5%) in the placebo group (unadjusted HR, 1.5; 95% CI, 1.1-2.0; P = .02). In a post hoc analysis, the 2-year cumulative incidence of hematological relapse was 33.5% (95% CI, 27.3%-39.7%) with azithromycin vs 22.3% (95% CI, 16.4%-28.2%) with placebo (unadjusted cause-specific HR, 1.7; 95% CI, 1.2-2.4; P = .002). Conclusions and Relevance: Among patients undergoing allogeneic HSCT for hematological malignancy, early administration of azithromycin resulted in worse airflow decline-free survival than did placebo; these findings are limited by early trial termination. The potential for harm related to relapse requires further investigation. Trial Registration: clinicaltrials.gov Identifier: NCT01959100.

Repeated systemic administration of adipose tissue-derived mesenchymal stem cells prevents tracheal obliteration in a murine model of bronchiolitis obliterans.

OBJECTIVE: To investigate the effect of adipose tissue-derived mesenchymal stem cell (ASC) administered either systemically or locally in a murine model of bronchiolitis obliterans. RESULTS: When compared to controls, systemic treatment with 106 ASCs on D0 and a second dose on D7 significantly prevented tracheal obliteration 28 days after heterotopic tracheal transplantation (median of 94 vs. 16%; P < 0.01). A single dose tended towards less stenosis than controls, but did not reach statistical significance (28 vs. 94%; P = 0.054). On the contrary, repeated local injection was incapable of preventing tracheal obliteration when compared to a single injection or controls (37 vs. 71 vs. 87%). Two intravenous doses also tended to be better than two local injections (16 vs. 37%; P = 0.058), and were better than a single local dose (16 vs. 71%; P < 0.01). CONCLUSION: A second dose of ASC, given systemically after 7 days, reduces luminal obliteration in a heterotopic tracheal transplantation model in mice, suggesting that ASC can be used to prevent obliterative bronchiolitis after lung transplantation.

Divergent Function of Programmed Death-Ligand 1 in Donor Tissue versus Recipient Immune System in a Murine Model of Bronchiolitis Obliterans.

Costimulatory molecules, such as the programmed death ligand (PD-L1), might exert differential effects on T-cell function, depending on the clinical setting and/or immunological environment. Given the impact of T cells on bronchiolitis obliterans (BO) in lung transplantation, we used an established tracheal transplant model inducing BO-like lesions to investigate the impact of PD-L1 on alloimmune responses and histopathological outcome in BO. In contrast to other transplant models in which PD-L1 generally shows protective functions, we demonstrated that PD-L1 has divergent effects depending on its location in donor versus recipient tissue. Although PD-L1 deficiency in donor tissue worsened histopathological outcome, and increased systemic inflammatory response, recipient PD-L1 deficiency induced opposite effects. Mechanistic studies revealed PD-L1-deficient recipients were hyporesponsive toward alloantigen, despite increased numbers of CD8+ effector T cells. The function of PD-L1 on T cells after unspecific stimulation was dependent on both cell type and strength of stimulation. This novel function of recipient PD-L1 may result from the high degree of T-cell activation within the highly immunogenic milieu of the transplanted tissue. In this model, both decreased T-cell alloimmune responses and the reduction of BO in PD-L1-deficient recipients suggest a potential therapeutic role of selectively blocking PD-L1 in the recipient. Further investigation is warranted to determine the impact of this finding embedded in the complex pathophysiological context of BO.

Pirfenidone ameliorates murine chronic GVHD through inhibition of macrophage infiltration and TGF-ß production.

Allogeneic hematopoietic stem cell transplantation is hampered by chronic graft-versus-host disease (cGVHD), resulting in multiorgan fibrosis and diminished function. Fibrosis in lung and skin leads to progressive bronchiolitis obliterans (BO) and scleroderma, respectively, for which new treatments are needed. We evaluated pirfenidone, a Food and Drug Administration (FDA)-approved drug for idiopathic pulmonary fibrosis, for its therapeutic effect in cGVHD mouse models with distinct pathophysiology. In a full major histocompatibility complex (MHC)-mismatched, multiorgan system model with BO, donor T-cell responses that support pathogenic antibody production are required for cGVHD development. Pirfenidone treatment beginning one month post-transplant restored pulmonary function and reversed lung fibrosis, which was associated with reduced macrophage infiltration and transforming growth factor-ß production. Pirfenidone dampened splenic germinal center B-cell and T-follicular helper cell frequencies that collaborate to produce antibody. In both a minor histocompatibility antigen-mismatched as well as a MHC-haploidentical model of sclerodermatous cGVHD, pirfenidone significantly reduced macrophages in the skin, although clinical improvement of scleroderma was only seen in one model. In vitro chemotaxis assays demonstrated that pirfenidone impaired macrophage migration to monocyte chemoattractant protein-1 (MCP-1) as well as IL-17A, which has been linked to cGVHD generation. Taken together, our data suggest that pirfenidone is a potential therapeutic agent to ameliorate fibrosis in cGVHD.

Utilization of the organ care system for bilateral lung transplantation: preliminary results of a comparative study.

OBJECTIVES: Lung transplantation (LTx) remains the gold standard for patients with end-stage lung disease. However, due to donor organ shortage and brain stem death-related lung injury, only a small proportion of lungs are used increasing the mortality rate on the waiting list. A portable normothermic continuous ex vivo perfusion using the organ care system (OCS) represents one of the tools to increase the pool of donor organs and to improve the function of marginal lungs. We sought to assess mid-term outcomes after LTx using OCS and to compare outcomes including overall survival and freedom from bronchiolitis obliterans syndrome (BOS) with those after conventional preservation. METHODS: Included were 322 consecutive LTx performed at Harefield Hospital between January 2007 and December 2014. Recipients were divided into two groups depending on the organ storage strategy: the majority of patients (n = 308) were transplanted using lungs after cold storage (cold storage group), whereas 14 organs were preserved using OCS (OCS group). The primary end-points were overall survival and freedom from BOS after LTx. The secondary end-points were perioperative clinical characteristics and adverse events. RESULTS: There were no statistically significant differences in terms of most baseline donor and recipient characteristics. The percentage of heavy smokers among donors [8 (2.9%) vs 6 (42.9%), P < 0.001] and the median number of pack-years smoked by donors [14 (7;24) vs 25 (24;30), P = 0.026] were statistically higher in the OCS group. Patients from the OCS group had significantly better postoperative FEV1 at 3 [69 (54;86) vs 93 (87;89), P < 0.001] and 6 [77 (60;90) vs 94 (84;100), P = 0.006] months. There were no statistically significant differences in terms of cumulative survival and freedom from BOS between the two groups. CONCLUSIONS: Results after LTx using OCS are acceptable with excellent survival, and superior early outcome in terms of postoperative lung function despite higher risk in the OCS group. Further larger prospective trials are warranted to confirm our preliminary results and to elaborate long-term outcomes.

B Cell-Activating Transcription Factor Plays a Critical Role in the Pathogenesis of Anti-Major Histocompatibility Complex-Induced Obliterative Airway Disease.

Antibodies (Abs) against major histocompatibility complex (MHC) results in T helper-17 (Th17)-mediated immunity against lung self-antigens (SAgs), K-α1 tubulin and collagen V and obliterative airway disease (OAD). Because B cell-activating transcription factor (BATF) controls Th17 and autoimmunity, we proposed that BATF may play a critical role in OAD. Anti-H2K(b) was administered intrabronchially into Batf (-/-) and C57BL/6 mice. Histopathology of the lungs on days 30 and 45 after Ab administration to Batf (-/-) mice resulted in decreased cellular infiltration, epithelial metaplasia, fibrosis, and obstruction. There was lack of Abs to SAgs, reduction of Sag-specific interleukin (IL)-17 T cells, IL-6, IL-23, IL-17, IL-1ß, fibroblast growth factor-6, and CXCL12 and decreased Janus kinase 2, signal transducer and activator of transcription 3 (STAT3), and retinoid-related orphan receptor γT. Further, micro-RNA (miR)-301a, a regulator of Th17, was reduced in Batf (-/-) mice in contrast to upregulation of miR-301a and downregulation of protein inhibitor of activated STAT3 (PIAS3) in anti-MHC-induced OAD animals. We also demonstrate an increase in miR-301a in the bronchoalveolar lavage cells from lung transplant recipients with Abs to human leukocyte antigen. This was accompanied by reduction in PIAS3 mRNA. Therefore, we conclude that BATF plays a critical role in the immune responses to SAgs and pathogenesis of anti-MHC-induced rejection. Targeting BATF should be considered for preventing chronic rejection after human lung transplantation.

The Selective JAK1/3-Inhibitor R507 Mitigates Obliterative Airway Disease Both With Systemic Administration and Aerosol Inhalation.

BACKGROUND: The efficacy of selective Janus kinase 1/3 inhibitor R507 to prevent obliterative airway disease was analyzed in preclinical airway transplantation models. METHODS: Orthotopic trachea transplantations were performed between Lewis donors and Brown Norway rat recipients. Oral everolimus (4 mg/kg once per day) or oral respective inhaled R507 (60 mg/kg twice per day, each) was used for immunosuppression. Grafts were retrieved after 6 or 60 days. Toxicity and anti-inflammatory effects of R507 were analyzed on human airway epithelial cells. RESULTS: In 6-day animals, oral and inhaled R507 more potently diminished mononuclear graft infiltration than everolimus and preserved ciliated pseudostratified columnar respiratory epithelium. Everolimus and R507 similarly suppressed systemic cellular and humoral immune activation. In untreated rats, marked obliterative airway disease developed over 60 days. Oral and inhaled R507 was significantly more effective in reducing airway obliteration and preserved the morphology of the airway epithelium. Luciferase-positive donors revealed that a substantial amount of smooth muscle cells within the obliterative tissue was of donor origin. Only everolimus but not R507, adversely altered kidney function and lipid profiles. The R507 aerosol did not show airway toxicity in vitro but effectively suppressed activation of inflammatory signaling pathways induced by IL-1ß. CONCLUSIONS: The Janus kinase 1/3 inhibitor R507 is a very well-tolerated immunosuppressant that similarly diminished obliterative airway disease with systemic or inhaled administration.