Elexacaftor-tezacaftor-ivacaftor decreases pseudomonas abundance in the sinonasal microbiome in cystic fibrosis

BACKGROUND

Chronic rhinosinusitis (CRS) is common in individuals with cystic fibrosis (CF) and is marked by chronic inflammation and episodes of infection that negatively impact quality of life. Several studies have shown that elexacaftor-tezacaftor-ivacaftor (ETI) improves symptoms and examination findings in CF-CRS. The current study determines the effect of ETI on the sinonasal microbiota in CF.

METHODS

Sinonasal samples were collected under endoscopic visualization before and after starting ETI. Samples were subjected to 16S amplicon sequencing and sequences were processed with the QIIME2 pipeline with subsequent analysis using the vegan R-package.

RESULTS

Twenty-nine individual baseline samples and 23 sample pairs pre-/post-ETI were available. At baseline, the cohort had samples dominated by Staphylococcus, and alpha diversity was lower than that of a published reference set of individuals without sinonasal disease. Individuals with prior sinus surgery had lower alpha diversity as measured by Shannon Index, Observed Richness, and Faith's phylogenetic diversity Index. Beta diversity differed between individuals with and without allergic rhinitis, with higher Staphylococcus abundance in those with allergic rhinitis. No change in alpha or beta diversity was seen after a median of 9 months on ETI. With ETI, the Pseudomonas genus and the genus containing Burkholderia decreased in samples containing these taxa at baseline. Pseudomonas abundance decreased with treatment as measured by qPCR. Core sinonasal microbiome members Staphylococcus, Corynebacterium, and Streptococcus were unchanged, while Moraxella increased with ETI.

CONCLUSIONS

Treatment with ETI leads to a reduction in Pseudomonas abundance within the sinonasal microbiome of individuals with Pseudomonas at baseline.

The effect of discontinuing hypertonic saline or dornase alfa on mucociliary clearance in elexacaftor/tezacaftor/ivacaftor treated people with cystic fibrosis: The SIMPLIFY-MCC Study

Many people with CF (pwCF) desire a reduction in inhaled treatment burden after initiation of elexacaftor/tezacaftor/ivacaftor. The randomized, open-label SIMPLIFY study showed that discontinuing hypertonic saline (HS) or dornase alfa (DA) was non-inferior to continuation of each treatment with respect to change in lung function over a 6-week period. In this SIMPLIFY substudy, we used gamma scintigraphy to determine whether discontinuation of either HS or DA was associated with deterioration in the rate of in vivo mucociliary clearance (MCC) in participants ≥12 years of age. While no significant differences in MCC endpoints were associated with HS discontinuation, significant improvement in whole and peripheral lung MCC was observed after discontinuing DA. These results suggest that pwCF on ETI with mild lung disease do not experience a subclinical deterioration in MCC that could later impact health outcomes after discontinuing HS, and in fact may benefit from improved MCC after stopping DA treatment.

A longitudinal analysis of respiratory symptoms in people with cystic fibrosis with advanced lung disease on and off ETI

People with CF (PwCF), particularly those with advanced lung disease (ALD), experience frequent respiratory symptoms. A major CF breakthrough was the approval of elexacaftor/tezacaftor/ivacaftor (ETI) in 2019, which has been shown to improve symptoms and lung function in the CF population, and decrease pulmonary exacerbations. The purpose of this study was to analyze longitudinal changes in respiratory symptoms over 24 months in ETI-treated and untreated PwCF with ALD Symptoms were measured among CF adults with ppFEV1 < 40% (N = 48, 24 ETI-treated, 24 untreated) using the CFRSD-CRISS and the CFQ-R [respiratory]. Two multilevel growth models assessed the rate of change in symptoms overall and within the ETI-treated and untreated groups. PwCF on ETI had significantly lower symptom severity over 24 months than those not on ETI as measured by the CRISS and CFQ-R. The ETI-treated group maintained an -11.7 and +19.3 point difference(p<0.01) in CRISS and CFQ-R scores over the study compared to the non-ETI group, achieving minimal clinically important differences on average between groups on both instruments. No change in the symptom burden trajectory between groups was observed (p = 0.58). Even with ALD, ETI-treated PwCF have a lower respiratory burden than those not on ETI. This may be confounded by survivorship bias in the non-ETI group. Of note, in this ALD cohort, neither instrument demonstrated ceiling effects. Our results suggest that, while ETI has significantly improved the lived experience, PwCF with ALD are still plagued by respiratory symptoms.

Effect of elexacaftor/tezacaftor/ivacaftor on mucus and mucociliary clearance in cystic fibrosis

BACKGROUND

The cystic fibrosis transmembrane conductance regulator (CFTR) modulator elexacaftor/tezacaftor/ivacaftor (E/T/I) is highly effective clinically for those with at least one F508del-CFTR allele. The effects of E/T/I on mucociliary clearance (MCC) and sputum properties are unknown. We, therefore, sought to characterize the effects of E/T/I on in vivo MCC and sputum characteristics hypothesized to impact mucus transport.

METHODS

Forty-four participants ≥12 years of age were enrolled into this prospective, observational trial prior to initiation of E/T/I and had baseline measurement of MCC and characterization of induced sputum and exhaled breath condensate (EBC) samples. Study procedures were repeated after 1 month of E/T/I treatment.

RESULTS

Average age was 27.7 years with baseline forced expiratory volume in 1 second (FEV1) of 78.2 % predicted. 52 % of subjects had previously been treated with a 2-drug CFTR modulator combination. The average whole lung MCC rate measured over 60 min (WLAveClr60) significantly improved from baseline to post-E/T/I (14.8 vs. 22.8 %; p = 0.0002), as did other MCC indices. Sputum% solids also improved (modeled mean 3.4 vs. 2.2 %; p<0.0001), whereas non-significant reductions in sputum macrorheology (G', G") were observed. No meaningful changes in exhaled breath condensate endpoints (sialic acid:urea ratio, pH) were observed.

CONCLUSIONS

E/T/I improved the hydration of respiratory secretions (% solids) and markedly accelerated MCC. These data confirm the link between CFTR function, mucus solid content, and MCC and help to define the utility of MCC and mucus-related bioassays in future efforts to restore CFTR function in all people with CF.

Role of Extracellular Vesicles in the Propagation of Lung Fibrosis in Systemic Sclerosis

OBJECTIVES

Systemic sclerosis (SSc) has the highest mortality rate among the rheumatic diseases, with lung fibrosis leading as the cause of death. A characteristic of severe SSc-related lung fibrosis is its progressive nature. Although most research has focused on the pathology of the fibrosis, the mechanism mediating the fibrotic spread remains unclear. We hypothesized that extracellular vesicle (EV) communication drives the propagation of SSc lung fibrosis.

METHODS

EVs were isolated from normal (NL) or SSc-derived human lungs and primary lung fibroblasts (pLFs). EVs were also isolated from human fibrotic lungs and pLFs induced experimentally with transforming growth factor-β (TGFβ). Fibrotic potency of EVs was assessed using functional assays in vitro and in vivo. Transmission electron microscopy, nanoparticle tracking analysis, real-time quantitative polymerase chain reaction (RT-qPCR), immunoblotting, and immunofluorescence were used to analyze EVs, their cargo, extracellular matrix (ECM) fractions, and conditioned media.

RESULTS

SSc lungs and pLFs released significantly more EVs than NL lungs, and their EVs showed increased fibrotic content and activity. TGFβ-stimulated NL lung cores and pLFs increased packaging of fibrotic proteins, including fibronectin, collagens, and TGFβ, into released EVs. The EVs induced a fibrotic phenotype in recipient pLFs and in vivo in mouse lungs. Furthermore, EVs interacted with and contributed to the ECM. Finally, suppressing EV release in vivo reduced severity of murine lung fibrosis.

CONCLUSIONS

Our findings highlight EV communication as a novel mechanism for propagation of SSc lung fibrosis. Identifying therapies that reduce EV release, activity, and/or fibrotic cargo in SSc patient lungs may be a viable therapeutic strategy to improve fibrosis.

Systems serology in cystic fibrosis: Anti-Pseudomonas IgG1 responses and reduced lung function

Nearly one-half of patients with cystic fibrosis (CF) carry the homozygous F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene but exhibit variable lung function phenotypes. How adaptive immunity influences their lung function remains unclear, particularly the serological antibody responses to antigens from mucoid Pseudomonas in sera from patients with CF with varying lung function. Sera from patients with CF with reduced lung function show higher anti-outer membrane protein I (OprI) immunoglobulin G1 (IgG1) titers and greater antibody-mediated complement deposition. Induction of anti-OprI antibody isotypes with complement activity enhances lung inflammation in preclinical mouse models. This enhanced inflammation is absent in immunized Rag2-/- mice and is transferrable to unimmunized mice through sera. In a CF cohort undergoing treatment with elexacaftor-tezacaftor-ivacaftor, the declination in anti-OprI IgG1 titers is associated with lung function improvement and reduced hospitalizations. These findings suggest that antibody responses to specific Pseudomonas aeruginosa (PA) antigens worsen lung function in patients with CF.

Feasibility Testing of a Web-Based Reproductive Decision Support Tool for Cystic Fibrosis

BACKGROUND

People with cystic fibrosis (CF) are increasingly considering their reproductive goals. We developed MyVoice:CF, a web-based patient-centered reproductive decision support tool and assessed its implementation in CF care.

METHODS

We conducted a feasibility trial among 18-44-year-old women with CF and multidisciplinary CF providers. Prior to CF clinic visit, patient participants completed a baseline survey, used MyVoice:CF, and assessed acceptability, appropriateness, and usability. After clinic, participants rated impact on reproductive health communication. At 3 months post-use, participants assessed impact on reproductive health outcomes. Provider participants completed a survey and focus group regarding MyVoice:CF feasibility/implementation. We assessed outcomes descriptively. We compared MyVoice:CF's impact on outcomes from baseline to follow-up using McNemar's and Wilcoxon signed rank tests as appropriate.

RESULTS

Forty-three patient participants completed baseline surveys and 40 rated MyVoice:CF's feasibility; 10 providers participated. Patient participants rated MyVoice:CF's acceptability as 4.48±0.50 out of 5, appropriateness as 4.61±0.48 out of 5, and usability as 82.25±11.02 ('A'/excellent). After MyVoice:CF use, participants reported improved reproductive health communication self-efficacy vs. baseline (3.54±1.17vs.3.95±0.93, p<0.001). At baseline, 36% of participants reported any discussion of reproductive goals/plans with their CF team in the past year compared to 59% after first visit post-MyVoice:CF use (p=0.049). Provider participants similarly rated MyVoice:CF as feasible and reported no negative impacts on clinic flow after implementation.

CONCLUSIONS

MyVoice:CF is acceptable, appropriate, and usable for those with CF. Preliminary effectiveness evaluation suggests that MyVoice:CF improves self-efficacy in and frequency of reproductive health communication. Future studies should further assess MyVoice:CF's impact on reproductive health communication and outcomes.

Advancing the pipeline of cystic fibrosis clinical trials: a new roadmap with a global trial network perspective

The growing use of modulator therapies aimed at restoring cystic fibrosis transmembrane conductance regulator (CFTR) protein function in people with cystic fibrosis has fundamentally altered clinical trial strategies needed to advance new therapeutics across an orphan disease population that is now divided by CFTR modulator eligibility. The development of a robust pipeline of nucleic acid-based therapies (NABTs)-initially directed towards the estimated 10% of the cystic fibrosis population who are genetically ineligible for, or intolerant of, CFTR modulators-is dependent on the optimisation of restricted trial participant resources across multiple development programmes, a challenge that will preclude the use of gold standard placebo-controlled trials. Advancement of a full pipeline of symptomatic therapies across the entire cystic fibrosis population will be challenged by smaller effect sizes and uncertainty regarding their clinical importance in a growing modulator-treated population with more mild and stable pulmonary disease. In this Series paper, we aim to lay the foundation for clinical trial strategy and community partnership that must deviate from established and familiar precedent to advance the future pipeline of cystic fibrosis therapeutics.

Lung transplant recipients with telomere-mediated pulmonary fibrosis have increased risk for hematologic complications

Idiopathic pulmonary fibrosis lung transplant recipients (IPF-LTRs) are enriched for short telomere length (TL) and telomere gene rare variants. A subset of patients with nontransplant short-TL are at increased risk for bone marrow (BM) dysfunction. We hypothesized that IPF-LTRs with short-TL and/or rare variants would be at increased risk for posttransplant hematologic complications. Data were extracted from a retrospective cohort of 72 IPF-LTRs and 72 age-matched non-IPF-LTR controls. Genetic assessment was done using whole genome sequencing or targeted sequence panel. TL was measured using flow cytometry and fluorescence in-situ hybridization (FlowFISH) and TelSeq software. The majority of the IPF-LTR cohort had short-TL, and 26% of IPF-LTRs had rare variants. Compared to non-IPF controls, short-TL IPF-LTRs were more likely to have immunosuppression agents discontinued due to cytopenias (P = .0375), and BM dysfunction requiring BM biopsy was more prevalent (29% vs 4%, P = .0003). IPF-LTRs with short-TL and rare variants had increased requirements for transfusion and growth factor support. Multivariable logistic regression demonstrated that short-TL, rare variants, and lower pretransplant platelet counts were associated with BM dysfunction. Pretransplant TL measurement and genetic testing for rare telomere gene variants identified IPF-LTRs at increased risk for hematologic complications. Our findings support stratification for telomere-mediated pulmonary fibrosis in lung transplant candidates.

Rabbit Antithymocyte Globulin for Treatment of Corticosteroid Refractory Acute Cellular Rejection After Lung Transplantation

BACKGROUND

Chronic lung allograft dysfunction (CLAD) remains a major cause of death after the first year posttransplant, with acute cellular rejection (ACR) being a major risk factor for CLAD. We evaluated the use of rabbit antithymocyte globulin (rATG) for corticosteroid refractory ACR in lung transplant recipients.

METHODS

We retrospectively identified 112 adult lung transplant recipients who received rATG for refractory ACR after lung transplantation. The primary endpoint was the incidence of ACR on follow-up transbronchial biopsy. Secondary endpoints included freedom from ACR within 1 y post-rATG, CLAD progression at 1 y post-rATG, and all-cause mortality at 1 y post-rATG.

RESULTS

A complete resolution of ACR was observed in 60.2% of patients, an improvement but not complete resolution in 22.1%, and no response on follow-up biopsy in 17.8%. Mean A grade 1 y post-rATG was 0.51 in complete responders, 1.01 in partial responders, and 2.19 in nonresponders ( P  < 0.001). Complete responders had significantly less new or worsening CLAD at 1 y than partial responders (17% versus 40%; P  = 0.02). All-cause mortality rate was 14.9% in complete responders, 40% in partial responders, and 30% in nonresponders ( P  < 0.01).

CONCLUSIONS

rATG appears to be an effective treatment of refractory ACR in lung transplant recipients. Failure to respond to rATG carries an increased risk of early CLAD and death.

Incidence of Acute Cellular Rejection After Granulocyte Colony-Stimulating Factor in Lung Transplant Recipients

BackgroundNeutropenia is a common complication in lung transplant recipients (LTRs). Filgrastim may be used to treat neutropenia in LTRs, but its consequences on acute cellular rejection (ACR) remain controversial. Objective: The purpose was to examine the association between filgrastim and incidence of ACR 6 months after filgrastim administration in LTRs. Secondary outcomes included burden of ACR, infections, chronic lung allograft dysfunction (CLAD), and survival. Methods: This was a matched cohort study of patients transplanted between January 2010 and October 2019. LTRs who received filgrastim for neutropenia were compared to a cohort who did not. LTRs were matched on transplant indication, sex, age, and time post-transplant and multivariable logistic regression models were used to evaluate the likelihood of ACR. Results: 212 patients were included in the analysis (106 in each group). 50 patients (47.2%) in the filgrastim group experienced ACR compared to 37 patients (34.9%) in the no filgrastim group (P = .070). In multivariable analysis, filgrastim use was not associated with ACR at 6 months (OR 1.409, 95% CI 0.772-2.571). Time to first ACR was shorter (P = .049) and 6-month ACR score was higher in the filgrastim group (.49 vs .33, P = .047). LTRs in the filgrastim group had higher incidence of bacterial pneumonia and 1-year mortality. Conclusions: Although not associated with increased likelihood of ACR at 6 months, our study found that filgrastim is associated with increased ACR burden and decreased time to ACR. This study can help inform clinicians of ACR risk after filgrastim use in LTRs.

Position paper: Models of post-transplant care for individuals with cystic fibrosis

There is no consensus on the best model of care for individuals with CF to manage the non-pulmonary complications that persist after lung transplant. The CF Foundation virtually convened a group of international experts in CF and lung-transplant care. The committee reviewed literature and shared the post-lung transplant model of care practiced by their programs. The committee then developed a survey that was distributed internationally to both the clinical and individual with CF/family audiences to determine the strengths, weaknesses, and preferences for various models of transplant care. Discussion generated two models to accomplish optimal CF care after transplant. The first model incorporates the CF team into care and proposes delineation of responsibilities for the CF and transplant teams. This model is reliant on outstanding communication between the teams, while leveraging the expertise of the CF team for management of the non-pulmonary manifestations of CF. The transplant team manages all aspects of the transplant, including pulmonary concerns and management of immunosuppression. The second model consolidates care in one center and may be more practical for transplant programs that have expertise managing CF and have access to CF multidisciplinary care team members (e.g., located in the same institution). The best model for each program is influenced by several factors and model selection needs to be decided between the transplant and the CF center and may vary from center to center. In either model, CF lung transplant recipients require a clear delineation of the roles and responsibilities of their providers and mechanisms for effective communication.

Embedded Specialist Palliative Care in Cystic Fibrosis: Results of a Randomized Feasibility Clinical Trial

Background: Cystic fibrosis (CF) is a progressive genetic disease characterized by multisystem symptom burden. Specialist palliative care (PC), as a model of care, has been shown to be effective in improving quality of life and reducing symptom burden in other conditions, but has not been tested in CF. Objectives: To develop and test the feasibility and acceptability of a specialist PC intervention embedded within an outpatient CF clinic. Design: Single-site, equal-allocation randomized pilot study comparing usual care with addition of four protocolized quarterly visits with a PC nurse practitioner. Participants: Adults with CF age ≥18 years with any of the following: FEV1% predicted ≤50, ≥2 CF-related hospitalizations in the past 12 months, supplemental oxygen use, or noninvasive mechanical ventilation use, and moderate-or-greater severity of any symptoms on the Edmonton Symptom Assessment Scale. Measurements: Randomization rate, intervention visit completion, data completements, participant ratings of intervention acceptability and benefit, and intervention delivery fidelity. Results: We randomized 50 adults with CF of 65 approached (77% randomization rate) to intervention (n = 25) or usual care (n = 25), mean age 38, baseline mean FEV1% predicted 41.8 (usual care), and 41.2 (intervention). No participants withdrew, five were lost to follow-up, and two died (88% retention). In the intervention group, 23 of 25 completed all study visits; 94% stated the intervention was not burdensome, and 97.6% would recommend the intervention to others with CF. More than 90% of study visits addressed topics prescribed by intervention manual. Conclusions: Adding specialist PC to standard clinic visits for adults with CF is feasible and acceptable.

Phage therapy in a lung transplant recipient with cystic fibrosis infected with multidrug-resistant Burkholderia multivorans

BACKGROUND

There is increased interest in bacteriophage (phage) therapy to treat infections caused by antibiotic-resistant bacteria. A lung transplant recipient with cystic fibrosis and Burkholderia multivorans infection was treated with inhaled phage therapy for 7 days before she died.

METHODS

Phages were given via nebulization through the mechanical ventilation circuit. Remnant respiratory specimens and serum were collected. We quantified phage and bacterial deoxyribonucleic acid (DNA) using quantitative polymerase chain reaction, and tested phage neutralization in the presence of patient serum. We performed whole genome sequencing and antibiotic and phage susceptibility testing on 15 B. multivorans isolates. Finally, we extracted lipopolysaccharide (LPS) from two isolates and visualized their LPS using gel electrophoresis.

RESULTS

Phage therapy was temporally followed by a temporary improvement in leukocytosis and hemodynamics, followed by worsening leukocytosis on day 5, deterioration on day 7, and death on day 8. We detected phage DNA in respiratory samples after 6 days of nebulized phage therapy. Bacterial DNA in respiratory samples decreased over time, and no serum neutralization was detected. Isolates collected between 2001 and 2020 were closely related but differed in their antibiotic and phage susceptibility profiles. Early isolates were not susceptible to the phage used for therapy, while later isolates, including two isolates collected during phage therapy, were susceptible. Susceptibility to the phage used for therapy was correlated with differences in O-antigen profiles of an early versus a late isolate.

CONCLUSIONS

This case of clinical failure of nebulized phage therapy highlights the limitations, unknowns, and challenges of phage therapy for resistant infections.

Reduced Cathepsin L expression and secretion into the extracellular milieu contribute to lung fibrosis in systemic sclerosis

OBJECTIVES

Lung fibrosis is the leading cause of death in SSc, with no cure currently available. Antifibrotic Endostatin (ES) production does not reach therapeutic levels in SSc patients, suggesting a deficit in its release from Collagen XVIII by the main cleavage enzyme, Cathepsin L (CTSL). Thus, elucidating a potential deficit in CTSL expression and activity unravels an underlying molecular cause for SSc-driven lung fibrosis.

METHODS

Fibrosis was induced experimentally using TGF-β in vitro, in primary human lung fibroblasts (pLFs), and ex vivo, in human lung tissues. ES and CTSL expression was quantified using ELISA, RT-qPCR, immunoblotting or immunofluorescence. Recombinant NC1-FLAG peptide was used to assess CTSL cleavage activity. CTSL expression was also compared between SSc vs normal (NL)-derived pLFs and lung tissues.

RESULTS

ES levels were significantly reduced in media conditioned by TGF-β-induced pLFs. TGF-β-stimulated pLFs significantly reduced expression and secretion of CTSL into the extracellular matrix (ECM). CTSL was also sequestered in its inactive form into extracellular vesicles, further reducing its availability in the ECM. Media conditioned by TGF-β-induced pLFs showed reduced cleavage of NC1-Flag and reduced release of the antifibrotic ES fragment. SSc-derived pLFs and lung tissues expressed significantly lower levels of CTSL compared with NL.

CONCLUSIONS

Our findings identify CTSL as a protein protective against lung fibrosis via its activation of antifibrotic ES, and whose expression in SSc pLFs and lung tissues is suppressed. Identifying strategies to boost CTSL endogenous levels in SSc patients could serve as a viable therapeutic strategy.

First Characterization of the Transcriptome of Lung Fibroblasts of SSc Patients and Healthy Donors of African Ancestry

Systemic sclerosis (SSc) is a connective tissue disorder that results in fibrosis of the skin and visceral organs. SSc-associated pulmonary fibrosis (SSc-PF) is the leading cause of death amongst SSc patients. Racial disparity is noted in SSc as African Americans (AA) have a higher frequency and severity of disease than European Americans (EA). Using RNAseq, we determined differentially expressed genes (DEGs; q < 0.1, log2FC > |0.6|) in primary pulmonary fibroblasts from SSc lungs (SScL) and normal lungs (NL) of AA and EA patients to characterize the unique transcriptomic signatures of AA-NL and AA-SScL fibroblasts using systems-level analysis. We identified 69 DEGs in "AA-NL vs. EA-NL" and 384 DEGs in "AA-SScL vs. EA-SScL" analyses, and a comparison of disease mechanisms revealed that only 7.5% of DEGs were commonly deregulated in AA and EA patients. Surprisingly, we also identified an SSc-like signature in AA-NL fibroblasts. Our data highlight differences in disease mechanisms between AA and EA SScL fibroblasts and suggest that AA-NL fibroblasts are in a "pre-fibrosis" state, poised to respond to potential fibrotic triggers. The DEGs and pathways identified in our study provide a wealth of novel targets to better understand disease mechanisms leading to racial disparity in SSc-PF and develop more effective and personalized therapies.

Ameliorating Fibrosis in Murine and Human Tissues with END55, an Endostatin-Derived Fusion Protein Made in Plants

Organ fibrosis, particularly of the lungs, causes significant morbidity and mortality. Effective treatments are needed to reduce the health burden. A fragment of the carboxyl-terminal end of collagen XVIII/endostatin reduces skin and lung fibrosis. This fragment was modified to facilitate its production in plants, which resulted in the recombinant fusion protein, END55. We found that expression of END55 had significant anti-fibrotic effects on the treatment and prevention of skin and lung fibrosis in a bleomycin mouse model. We validated these effects in a second mouse model of pulmonary fibrosis involving inducible, lung-targeted expression of transforming growth factor β1. END55 also exerted anti-fibrotic effects in human lung and skin tissues maintained in organ culture in which fibrosis was experimentally induced. The anti-fibrotic effect of END55 was mediated by a decrease in the expression of extracellular matrix genes and an increase in the levels of matrix-degrading enzymes. Finally, END55 reduced fibrosis in the lungs of patients with systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF) who underwent lung transplantation due to the severity of their lung disease, displaying efficacy in human tissues directly relevant to human disease. These findings demonstrate that END55 is an effective anti-fibrotic therapy in different organs.

Nasal epithelial cell culture fluorescence recovery after photobleaching predicts cystic fibrosis therapeutic response

Background

Human nasal epithelial (HNE) cells can be sampled noninvasively and cultured to provide a model of the airway epithelium that reflects cystic fibrosis (CF) pathophysiology. We hypothesised that in vitro measures of HNE cell physiology would correlate directly with in vivo measures of lung physiology and therapeutic response, providing a framework for using HNE cells for therapeutic development and precision medicine.

Methods

We sampled nasal cells from participants with CF (CF group, n=26), healthy controls (HC group, n=14) and single CF transmembrane conductance regulator (CFTR) mutation carrier parents of the CF group (CR group, n=16). Participants underwent lung physiology and sweat chloride testing, and nuclear imaging-based measurement of mucociliary clearance (MCC) and small-molecule absorption (ABS). CF participants completed a second imaging day that included hypertonic saline (HS) inhalation to assess therapeutic response in terms of MCC. HNE measurements included Ussing chamber electrophysiology, small-molecule and liquid absorption rates, and particle diffusion rates through the HNE airway surface liquid (ASL) measured using fluorescence recovery after photobleaching (FRAP).

Results

Long FRAP diffusion times were associated with increased MCC response to HS in CF. This implies a strong relationship between inherent factors affecting ASL mucin concentration and therapeutic response to a hydrating therapy. MCC decreased with age in the CR group, which had a larger range of ages than the other two groups. Likely this indicates a general age-related effect that may be accentuated in this group. Measures of lung ABS correlated with sweat chloride in both the HC and CF groups, indicating that CFTR function drives this measure of paracellular small-molecule probe absorption.

Conclusions

Our results demonstrate the utility of HNE cultures for assessing therapeutic response for hydrating therapies. In vitro measurements of FRAP were particularly useful for predicting response and for characterising important properties of ASL mucus that were ultimately reflected in lung physiology.

Elexacaftor-Tezacaftor- Ivacaftor improves sinonasal outcomes in cystic fibrosis

BACKGROUND

Many individuals with cystic fibrosis (CF) have chronic rhinosinusitis resulting in nasal obstruction, sinus infections, and repeated surgeries. Elexacaftor-tezacaftor-ivacaftor is a highly effective modulator therapy approved for individuals aged 6 years or older with CF who have at least one F508del allele or other responsive mutation. The current study tests the hypothesis that ELX/TEZ/IVA improves sinonasal disease in CF.

METHODS

The study was a pre/post, observational cohort study conducted at two sites. Participants underwent a study visit prior to starting ELX/TEZ/IVA and a second visit at a median of 9 months on therapy. Each visit included sinus CT scan, rigid nasal endoscopy, and sweat chloride measurement. Symptoms were measured with the 22 item Sinonasal Outcome Test at scheduled intervals during the study. Regression models were used to test for improvement in symptoms, endoscopy, and CT scales.

RESULTS

The study enrolled 34 individuals, with a median age of 27 years (range 12-60). Symptoms improved within 7 days of therapy and plateaued by day 28. Endoscopic crusting resolved and nasal polyposis improved, with a decrease in size or resolution of polyps. Sinus opacification and mucosal thickening improved on CT radiographs with treatment.

CONCLUSIONS

Sinonasal symptoms improved rapidly and durably for at least 180 days on ELX/TEZ/IVA therapy. Objective measures of disease including endoscopic and CT findings improved with ELX/TEZ/IVA.

Use of elexacaftor/tezacaftor/ivacaftor among cystic fibrosis lung transplant recipients

BACKGROUND

Cystic fibrosis (CF) lung transplant (LT) recipients may warrant treatment with elexacaftor/tezacaftor/ivacaftor (ETI) to improve extrapulmonary manifestations of CF. Our objectives were to identify reasons for prescribing ETI after LT and evaluate changes in body mass index (BMI), hemoglobin A1c, hemoglobin, and liver enzymes.

METHODS

This was an electronic health record-based cohort study, October 2019-September 2020, at 14 CF LT Consortium sites in North America. The study included CF LT recipients prescribed ETI after transplant. Differences in BMI, A1c, and hemoglobin were assessed with paired t-tests.

RESULTS

There were 94 patients prescribed ETI; indications included sinus disease (68%), GI symptoms (39%), or low BMI (19%). Prescriptions were written by CF physicians (34%), LT physicians (27%), or physicians who practice both CF and LT (39%). Forty patients (42%) stopped ETI at a median of 56 days [IQR 26, 139] after start/prescription date. ETI was not associated with a significant change in BMI (0.2 kg/m2, 95% CI [-0.1, 0.6], p = 0.150), but was associated with decreased A1c (0.4%, 95% CI 0.2, 0.7, p = 0.003), and increased hemoglobin for patients with anemia (0.6 g/dL, 95% CI 0.2, 1.0, p = 0.007). Three people (3%) stopped ETI due to elevated transaminases.

CONCLUSIONS

ETI is rarely prescribed for non-pulmonary indications after LT for CF. Further study is needed to determine the risks and benefits of ETI in the CF lung transplant population given the potential for drug interactions, side effects leading to discontinuation of ETI, and the possible mechanisms for ETI to positively impact long-term post-transplant outcomes.

Prospective Evaluation of Coronavirus Disease 2019 (COVID-19) Vaccine Responses Across a Broad Spectrum of Immunocompromising Conditions: the COVID-19 Vaccination in the Immunocompromised Study (COVICS)

BACKGROUND

We studied humoral responses after coronavirus disease 2019 (COVID-19) vaccination across varying causes of immunodeficiency.

METHODS

Prospective study of fully vaccinated immunocompromised adults (solid organ transplant [SOT], hematologic malignancy, solid cancers, autoimmune conditions, human immunodeficiency virus [HIV]) versus nonimmunocompromised healthcare workers (HCWs). The primary outcome was the proportion with a reactive test (seropositive) for immunoglobulin G to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain. Secondary outcomes were comparisons of antibody levels and their correlation with pseudovirus neutralization titers. Stepwise logistic regression was used to identify factors associated with seropositivity.

RESULTS

A total of 1271 participants enrolled: 1099 immunocompromised and 172 HCW. Compared with HCW (92.4% seropositive), seropositivity was lower among participants with SOT (30.7%), hematological malignancies (50.0%), autoimmune conditions (79.1%), solid tumors (78.7%), and HIV (79.8%) (P < .01). Factors associated with poor seropositivity included age, greater immunosuppression, time since vaccination, anti-CD20 monoclonal antibodies, and vaccination with BNT162b2 (Pfizer) or adenovirus vector vaccines versus messenger RNA (mRNA)-1273 (Moderna). mRNA-1273 was associated with higher antibody levels than BNT162b2 or adenovirus vector vaccines after adjusting for time since vaccination, age, and underlying condition. Antibody levels were strongly correlated with pseudovirus neutralization titers (Spearman r = 0.89, P < .0001), but in seropositive participants with intermediate antibody levels, neutralization titers were significantly lower in immunocompromised individuals versus HCW.

CONCLUSIONS

Antibody responses to COVID-19 vaccines were lowest among SOT and anti-CD20 monoclonal recipients, and recipients of vaccines other than mRNA-1273. Among those with intermediate antibody levels, pseudovirus neutralization titers were lower in immunocompromised patients than HCWs. Additional SARS-CoV-2 preventive approaches are needed for immunocompromised persons, which may need to be tailored to the cause of immunodeficiency.

Induction Strategies in Lung Transplantation: Alemtuzumab vs. Basiliximab a Single-Center Experience

Background

Induction therapy is used in about 80% of lung transplant centers and is increasing globally. Currently, there are no standards or guidelines for the use of induction therapy. At our institution, we have two induction strategies, basiliximab, and alemtuzumab. The goal of this manuscript is to share our experience and practice since this is an area of controversy.

Methods

We retrospectively reviewed 807 lung transplants performed at our institution between 2011 and 2020. Indications for the use of the basiliximab protocol were as follows: patients over the age of 70 years, history of cancer, hepatitis C virus or human immunodeficiency virus infection history, and cytomegalovirus or Epstein-Barr virus (donor positive/ recipient negative). In the absence of these clinical factors, the alemtuzumab protocol was used.

Results

453 patients underwent alemtuzumab induction and 354 patients underwent basiliximab. There were significant differences in delayed chest closure (24.7% alemtuzumab vs 31.4% basiliximab, p = 0.037), grade 3 primary graft dysfunction observed within 72 hours (19.9% alemtuzumab vs 29.9% basiliximab, p = 0.002), postoperative hepatic dysfunction (8.8% alemtuzumab vs 14.7% basiliximab, p = 0.009), acute cellular rejection in first year (39.1% alemtuzumab vs 53.4% basiliximab, p < 0.001). The overall survival rate of the patients with alemtuzumab induction was significantly higher than those of the patients with basiliximab induction (5 years survival rate: 64.1% alemtuzumab vs 52.3%, basiliximab, p < 0.001). Multivariate Cox regression analysis confirmed lower 5-year survival for basiliximab induction (HR = 1.41, p = 0.02), recipient cytomegalovirus positive (HR = 1.49, p = 0.01), postoperative hepatic dysfunction (HR = 2.20, p < 0.001), and acute kidney injury requiring renal replacement therapy (HR = 2.27, p < 0.001).

Conclusions

In this single center retrospective review, there was a significant difference in survival rates between induction strategies. This outcome may be attributable to differences in recipient characteristics between the groups. However, the Alemtuzumab group experienced less episodes of acute cellular rejection within the first year.

CD4+ T-Cell Dysfunction in Severe COVID-19 Disease Is Tumor Necrosis Factor-α/Tumor Necrosis Factor Receptor 1-Dependent

Rationale: Lymphopenia is common in severe coronavirus disease (COVID-19), yet the immune mechanisms are poorly understood. As inflammatory cytokines are increased in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we hypothesized a role in contributing to reduced T-cell numbers. Objectives: We sought to characterize the functional SARS-CoV-2 T-cell responses in patients with severe versus recovered, mild COVID-19 to determine whether differences were detectable. Methods: Using flow cytometry and single-cell RNA sequence analyses, we assessed SARS-CoV-2-specific responses in our cohort. Measurements and Main Results: In 148 patients with severe COVID-19, we found lymphopenia was associated with worse survival. CD4⁺ lymphopenia predominated, with lower CD4⁺/CD8⁺ ratios in severe COVID-19 compared with patients with mild disease (P < 0.0001). In severe disease, immunodominant CD4⁺ T-cell responses to Spike-1 (S1) produced increased in vitro TNF-α (tumor necrosis factor-α) but demonstrated impaired S1-specific proliferation and increased susceptibility to activation-induced cell death after antigen exposure. CD4⁺TNF-α⁺ T-cell responses inversely correlated with absolute CD4⁺ counts from patients with severe COVID-19 (n = 76; R = -0.797; P < 0.0001). In vitro TNF-α blockade, including infliximab or anti-TNF receptor 1 antibodies, strikingly rescued S1-specific CD4⁺ T-cell proliferation and abrogated S1-specific activation-induced cell death in peripheral blood mononuclear cells from patients with severe COVID-19 (P < 0.001). Single-cell RNA sequencing demonstrated marked downregulation of type-1 cytokines and NFκB signaling in S1-stimulated CD4⁺ cells with infliximab treatment. We also evaluated BAL and lung explant CD4⁺ T cells recovered from patients with severe COVID-19 and observed that lung T cells produced higher TNF-α compared with peripheral blood mononuclear cells. Conclusions: Together, our findings show CD4⁺ dysfunction in severe COVID-19 is TNF-α/TNF receptor 1-dependent through immune mechanisms that may contribute to lymphopenia. TNF-α blockade may be beneficial in severe COVID-19.

Outpatient Pharmacologic Management of Lung Transplant Candidates on the Waiting List

The medical care of patients awaiting lung transplantation is complex and requires the treatment of active medical conditions, including lung disease, while at the same time maintaining candidacy for transplantation. Some medications that would otherwise be considered routine may create undesirable challenges or complications in the perioperative setting. Therefore, a comprehensive assessment of the risks and benefits of these medications must take into account both their potential utility in managing a patient's current disease state, as well as the risks of compromising postlung transplant outcomes. In this review, we summarize the available data regarding several medications that are commonly used to treat patients with a variety of lung diseases, but that may impact a patient's course on the waiting list or in the posttransplant period.

Risk factors of bronchial dehiscence after primary lung transplantation

BACKGROUND

Although the incidence of bronchial dehiscence following lung transplantation has decreased significantly due to improvements in perioperative managements and surgical techniques, it remains a devastating postoperative complication associated with high morbidity and mortality.

METHODS

We retrospectively reviewed 811 lung transplantation performed at our institution between January 2011 and December 2020. Bronchial dehiscence was confirmed with flexible bronchoscopy, computed tomography (CT) scan, or clinical findings grade using International Society for Heart and Lung Transplantation recommendations.

RESULTS

Bronchial dehiscence was diagnosed in 38 patients (4.7%). The overall survival rates of the patients with bronchial dehiscence were significantly worse than those of the patients without bronchial dehiscence (p = .003). Multivariate analysis identified use of our basiliximab induction protocol (odds ratio = 3.03, p = .008) as an independent predictive factor of postoperative airway dehiscence in our multivariable model, along with total ventilator duration (odds ratio = 1.02, p = .002).

CONCLUSIONS

Based on our analysis, patients that underwent our basiliximab induction protocol for lung transplantation experienced a higher rate of postoperative bronchial dehiscence when compared with patients who receive alemtuzumab induction. We believe this may be associated with a higher steroid exposure in this population. Additional studies are necessary to further characterize the relationship between different induction protocols and bronchial dehiscence following transplantation.

Effect of lumacaftor-ivacaftor on mucociliary clearance and clinical outcomes in cystic fibrosis: Results from the PROSPECT MCC sub-study

CFTR function is required for normal mucociliary clearance (MCC) and cough-assisted clearance (CC). Lumacaftor-ivacaftor is approved for use in people with cystic fibrosis (CF) carrying two copies of F508del-CFTR. In this observational study performed at four study sites, we characterized the effect of lumacaftor-ivacaftor on mucociliary and cough clearance and related this to other clinical and research endpoints after one month of treatment. Twenty-five adolescents and adults were enrolled. No effect on whole lung MCC was observed, but CC was significantly increased. Sweat chloride improved by 18 mEq/L in this group, indicating a modest restoration of CFTR activity, but no demonstrable change in FEV₁ or lung clearance index was observed. We speculate that the modest effect of lumacaftor-ivacaftor on CFTR function was insufficient to yield an improvement in MCC.

Acidic Microenvironment Determines Antibiotic Susceptibility and Biofilm Formation of Pseudomonas aeruginosa

Pseudomonas aeruginosa is the most prevalent bacterial species that contribute to cystic fibrosis (CF) respiratory failure. The impaired function of CF transmembrane conductance regulator leads to abnormal epithelial Cl^-/HCO₃ ^- transport and acidification of airway surface liquid. However, it remains unclear why the CF lung is most commonly infected by Pseudomonas aeruginosa versus other pathogens. We carried out studies to investigate if lower pH helps Pseudomonas aeruginosa adapt and thrive in the CF-like acidic lung environment. Our results revealed that Pseudomonas aeruginosa generally forms more biofilm, induces antibiotic resistance faster in acidic conditions, and can be reversed by returning the acidic environment to physiologically neutral conditions. Pseudomonas aeruginosa appears to be highly adaptive to the CF-like acidic pH environment. By studying the effects of an acidic environment on bacterial response, we may provide a new therapeutic option in preventing chronic Pseudomonas aeruginosa infection and colonization.

Lung transplantation for idiopathic pulmonary fibrosis enriches for individuals with telomere-mediated disease

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the most common indication for lung transplantation in North America and variants in telomere-maintenance genes are the most common identifiable cause of IPF. We reasoned that younger IPF patients are more likely to undergo lung transplantation and we hypothesized that lung transplant recipients would be enriched for individuals with telomere-mediated disease due to the earlier onset and more severe disease in these patients.

METHODS

Individuals with IPF who underwent lung transplantation or were evaluated in an interstitial lung disease specialty clinic who did not undergo lung transplantation were examined. Genetic evaluation was completed via whole genome sequencing (WGS) of 426 individuals and targeted sequencing for 5 individuals. Rare variants in genes previously associated with IPF were classified using the American College of Medical Genetics guidelines. Telomere length from WGS data was measured using TelSeq software. Patient characteristics were collected via medical record review.

RESULTS

Of 431 individuals, 149 underwent lung transplantation for IPF. The median age of diagnosis of transplanted vs non-transplanted individuals was significantly younger (60 years vs 70 years, respectively, p<0.0001). IPF lung transplant recipients (IPF-LTRs) were twice as likely to have telomere-related rare variants compared to non-transplanted individuals (24% vs 12%, respectively, p=0.0013). IPF-LTRs had shorter telomeres than non-transplanted IPF patients (p=0.0028) and >85% had telomeres below the age-adjusted mean. Post-transplant survival and CLAD were similar amongst IPF-LTRs with rare variants in telomere-maintenance genes compared to those without, as well as in those with short telomeres versus longer telomeres.

CONCLUSIONS

There is an enrichment for telomere-maintenance gene variants and short telomeres among IPF-LTRs. However, transplant outcomes of survival and CLAD do not differ by gene variants or telomere length within IPF-LTRs. Our findings support individual with telomere-mediated disease should not be excluded from lung transplantation and focusing research efforts on therapies directed toward individuals with short-telomere mediated disease.

HLA-C and KIR permutations influence chronic obstructive pulmonary disease risk

A role for hereditary influences in the susceptibility for chronic obstructive pulmonary disease (COPD) is widely recognized. Cytotoxic lymphocytes are implicated in COPD pathogenesis, and functions of these leukocytes are modulated by interactions between their killer cell Ig-like receptors (KIR) and human leukocyte antigen–Class I (HLA–Class I) molecules on target cells. We hypothesized HLA–Class I and KIR inheritance affect risks for COPD. HLA–Class I alleles and KIR genotypes were defined by candidate gene analyses in multiple cohorts of patients with COPD (total n = 392) and control smokers with normal spirometry (total n = 342). Compared with controls, patients with COPD had overrepresentations of HLA-C*07 and activating KIR2DS1, with underrepresentations of HLA-C*12. Particular HLA-KIR permutations were synergistic; e.g., the presence of HLA-C*07 + KIR2DS1 + HLA-C12^null versus HLAC*07^null + KIR2DS1^null + HLA-C12 was associated with COPD, especially among HLA-C1 allotype homozygotes. Cytotoxicity of COPD lymphocytes was more enhanced by KIR stimulation than those of controls and was correlated with lung function. These data show HLA-C and KIR polymorphisms strongly influence COPD susceptibility and highlight the importance of lymphocyte-mediated cytotoxicity in COPD pathogenesis. Findings here also indicate that HLA-KIR typing could stratify at-risk patients and raise possibilities that HLA-KIR axis modulation may have therapeutic potential.

Type-1 immunity and endogenous immune regulators predominate in the airway transcriptome during chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) remains the major complication limiting long-term survival among lung transplant recipients (LTRs). Limited understanding of CLAD immunopathogenesis and a paucity of biomarkers remain substantial barriers for earlier detection and therapeutic interventions for CLAD. We hypothesized the airway transcriptome would reflect key immunologic changes in disease. We compared airway brush-derived transcriptomic signatures in CLAD (n = 24) versus non-CLAD (n = 21) LTRs. A targeted assessment of the proteome using concomitant bronchoalveolar lavage (BAL) fluid for 24 cytokines/chemokines and alloimmune T cell responses was performed to validate the airway transcriptome. We observed an airway transcriptomic signature of differential genes expressed (DGEs) in CLAD marked by Type-1 immunity and striking upregulation of two endogenous immune regulators: indoleamine 2, 3 dioxygenase 1 (IDO-1) and tumor necrosis factor receptor superfamily 6B (TNFRSF6B). Advanced CLAD staging was associated with a more intense airway transcriptome signature. In a validation cohort using the identified signature, we found an area under the curve (AUC) of 0.77 for CLAD LTRs. Targeted proteomic analyses revealed a predominant Type-1 profile with detection of IFN-γ, TNF-α, and IL-1β as dominant CLAD cytokines, correlating with the airway transcriptome. The airway transcriptome provides novel insights into CLAD immunopathogenesis and biomarkers that may impact diagnosis of CLAD.

Challenges in the use of highly effective modulator treatment for cystic fibrosis

The last decade has seen development of oral, small molecule therapies that address the basic cystic fibrosis transmembrane conductance regulator (CFTR) protein defect. Highly effective modulator treatment (HEMT) that is efficacious for a large majority of people living with cystic fibrosis (CF) promises to change the landscape of this chronic life-limiting disease. Some people living with CF have a CFTR genotype that renders them eligible for HEMT, but also have comorbidities that excluded them from the original Phase III clinical trials that led to US Food and Drug Administration approval. The purpose of this review is to address the use of HEMT in challenging situations, including initiation for those with advanced CF lung disease, and use after solid organ transplant, during pregnancy, and for individuals with CFTR-related disorders without a definitive diagnosis of CF.

Donor-specific antibody characteristics, including persistence and complement-binding capacity, increase risk for chronic lung allograft dysfunction

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is the major complication limiting long-term survival in lung transplant recipients (LTRs), with those developing donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) previously found to have increased risk for CLAD. However, as DSA responses vary in timing of development, specificity, breadth, persistence, and complement-binding capacity, we hypothesized that these characteristics would impact CLAD and survival outcomes.

METHODS

We retrospectively analyzed DSA characteristics and outcomes in a single-center cohort of 582 LTRs who had serum samples collected prospectively from 2010 to 2016. Luminex-based single antigen bead assays were performed to assess DSA.

RESULTS

DSAs were detected in 247 LTRs (42%), of which 124 (21.3%) were de novo DSAs and 53 (9.1%) were complement-binding (C1q+). CLAD developed in 208 LTRs (35.7%) during the follow-up period, with 67.8% determined as bronchiolitis obliterans syndrome phenotype and 32.2% as restrictive allograft syndrome phenotype. We found a shorter time to CLAD in LTRs with persistent DSAs (p = 0.04) and HLA-DQ-specific DSAs (p = 0.03). LTRs who developed C1q+ DSAs had significantly shorter time to CLAD (p < 0.001), with 100% of C1q+ DSAs being persistent and no differences between CLAD phenotypes. CLAD-free survival was significantly reduced in LTRs who developed C1q+ DSAs (p = 0.001), HLA-DQ-specific DSAs (p = 0.03), and multiple DSAs (p = 0.02).

CONCLUSIONS

Together, our findings demonstrate that DSA characteristics of persistence, HLA-DQ specificity, and C1q+ DSAs are associated with shorter time to CLAD. Additionally, C1q+, HLA-DQ-specific, and multiple DSAs are associated with decreased CLAD-free survival. These characteristics may improve DSA risk stratification for deleterious outcomes in LTRs.

Incorporating patient and caregiver feedback into lung transplant referral guidelines for individuals with cystic fibrosis-Preliminary findings from a novel paradigm

BACKGROUND

Lung transplantation is a common therapeutic option for individuals with cystic fibrosis (CF) and advanced lung disease, yet many individuals with CF are not appropriately referred for evaluation. The present study sought to enhance CF transplant referral guidelines by integrating patient-centered input to identify possible psychosocial barriers contributing to suboptimal referral for appropriate CF transplant candidates.

METHODS

As a component of developing the Cystic Fibrosis Foundation (CFF) Lung Transplant Referral Consensus Guidelines, we convened a focus group of lung transplant recipients with CF and two spouses of CF recipients. Each session involved standardized approaches to elicit qualitative, thematic content.

RESULTS

CF patients and caregivers characterized five areas for improvement, which were integrated into formal CFF referral guidelines. These included (a) timing of transplant discussion with CF providers, (b) accuracy of transplant-related knowledge and expectations, (c) stigma associated with the need for transplantation, (d) treatment team transition issues, and (e) social support and mental health concerns. Earlier introduction of transplant, greater details regarding manageable aspects of treatment, and greater provision of social support were all associated with better psychosocial experiences.

CONCLUSIONS

Integrating patient-centered input into guideline development yielded important and previously unknown psychosocial barriers contributing to suboptimal transplant referral.

Idiopathic pulmonary fibrosis lung transplant recipients are at increased risk for EBV-associated posttransplant lymphoproliferative disorder and worse survival

Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorder (EBV-PTLD) is a serious complication in lung transplant recipients (LTRs) associated with significant mortality. We performed a single-center retrospective study to evaluate the risks for PTLD in LTRs over a 7-year period. Of 611 evaluable LTRs, we identified 28 cases of PTLD, with an incidence of 4.6%. Kaplan-Meier analysis showed a decreased freedom from PTLD in idiopathic pulmonary fibrosis (IPF)-LTRs (P < .02). Using a multivariable Cox proportional hazards model, we found IPF (hazard ratio [HR] 3.51, 95% confidence interval [CI] 1.33-8.21, P = .01) and alemtuzumab induction therapy (HR 2.73, 95% CI 1.10-6.74, P = .03) as risk factors for PTLD, compared to EBV mismatch (HR: 34.43, 95% CI 15.57-76.09, P < .0001). Early PTLD (first year) was associated with alemtuzumab use (P = .04), whereas IPF was a predictor for late PTLD (after first year) (P = .002), after controlling for age and sex. Kaplan-Meier analysis revealed a shorter time to death from PTLD in IPF LTRs compared to other patients (P = .04). The use of alemtuzumab in EBV mismatch was found to particularly increase PTLD risk. Together, our findings identify IPF LTRs as a susceptible population for PTLD. Further studies are required to understand the mechanisms driving PTLD in IPF LTRs and develop strategies to mitigate risk.

Transcriptomic Responses to Ivacaftor and Prediction of Ivacaftor Clinical Responsiveness

Ivacaftor is a drug that was recently approved by the U.S. Food and Drug Administration for the treatment of patients with cystic fibrosis (CF) and at least one copy of the G511D mutation in the CFTR (CF transmembrane conductance regulator) gene. The transcriptomic effect of ivacaftor in patients with CF remains unclear. Here, we sought to examine whether and how the transcriptome of patients is influenced by ivacaftor treatment, and to determine whether these data allow prediction of ivacaftor responsiveness. Our data originated from the G551D Observational Study (GOAL). We performed RNA sequencing (RNA-seq) on peripheral blood mononuclear cells (PBMCs) from 56 patients and compared the transcriptomic changes that occurred before and after ivacaftor treatment. We used consensus clustering to stratify patients into subgroups based on their clinical responses after treatment, and we determined differences between subgroups in baseline gene expression. A random forest model was built to predict ivacaftor responsiveness. We identified 239 genes (false discovery rate < 0.1) that were significantly influenced by ivacaftor in PBMCs. The functions of these genes relate to cell differentiation, microbial infection, inflammation, Toll-like receptor signaling, and metabolism. We classified patients into "good" and "moderate" responder groups based on their clinical response to ivacaftor. We identified a panel of signature genes and built a statistical model for predicting CFTR modulator responsiveness. Despite a limited sample size, adequate prediction performance was achieved with an accuracy of 0.92. In conclusion, for the first time, the present study demonstrates profound transcriptomic impacts of ivacaftor in PBMCs from patients with CF, and provides a pilot statistical model for predicting clinical responsiveness to ivacaftor before treatment.

Intracellular Heat Shock Protein 70 Deficiency in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) pathogenesis has been postulated to involve a variety of mechanisms associated with the aging process, including loss of protein homeostasis (proteostasis). Heat shock proteins are cellular chaperones that serve a number of vital maintenance and repair functions, including the regulation of proteostasis. Previously published data have implicated heat shock protein 70 (Hsp70) in the development of pulmonary fibrosis in animal models. We sought to identify alterations in Hsp70 expression in IPF lung. Hsp70 mRNA and protein were decreased in primary fibroblasts cultured from IPF versus normal donor lung tissue. In addition to cultured fibroblasts, Hsp70 expression was decreased in intact IPF lung, a stressed environment in which upregulation of protective heat shock proteins would be anticipated. In support of a mechanistic association between decreased Hsp70 and fibrosis, cultured primary lung fibroblasts deficient in Hsp70 secreted increased extracellular matrix proteins. Treatment of primary normal human lung fibroblasts in vitro with either of the profibrotic molecules IGFBP5 (insulin-like growth factor-binding protein 5) or transforming growth factor-β1 downregulated Hsp70, suggesting Hsp70 is a downstream target in the fibrotic cascade. Hsp70-knockout mice subjected to an inhalational bleomycin model of pulmonary fibrosis demonstrated accelerated fibrosis versus wild-type control animals. We therefore conclude that reduced Hsp70 protein contributes to fibrosis and that interventions aimed at restoring normal expression of Hsp70 represent a novel therapeutic strategy for pulmonary fibrosis.

Underweight Patients With Cystic Fibrosis Have Acceptable Survival Following Lung Transplantation: A United Network for Organ Sharing Registry Study

BACKGROUND

Reduced BMI is an absolute contraindication for lung transplantation (LTx) at most centers in the United States. The objective of this study was to quantify post-LTx survival of moderate to severely underweight patients with cystic fibrosis (CF) (BMI < 17 kg/m²) in the United States relative to normal-weight recipients with CF and other frequently transplanted patient cohorts.

METHODS

Using United Network for Organ Sharing Registry data (undergoing transplant from June 2005-November 2015), Kaplan-Meier estimates of median posttransplant survival were calculated for all patients with CF, COPD, and idiopathic pulmonary fibrosis (IPF), as well as low and normal weight CF subgroups. Cox regression modeling stratified according to transplant center assessed risk of posttransplant mortality in recipients with CF and a BMI < 17 kg/m² compared with recipients with COPD (reference).

RESULTS

Median posttransplant survival (95% CI) for CF, COPD, and IPF was 7.9 (7.2-8.6), 5.9 (5.6-6.2), and 5.5 (5.2-5.8) years, respectively. Although an absolute decrease was noted in posttransplant survival for recipients with CF and a BMI < 17 kg/m², compared with those with CF and a BMI ≥ 17 kg/m² (7.0 years [4.5-7.9] vs 8.2 years [7.3-9.0]), Cox modeling found no increased mortality risk (adjusted hazard ratio, 1.09; 95% CI, 0.90-1.32; P = .38). There was no difference in posttransplant mortality between patients with CF and a BMI < 17 kg/m² and recipients with COPD and all BMIs (adjusted hazard ratio, 1.04; 95% CI, 0.86-1.25; P = .71).

CONCLUSIONS

Transplant recipients with CF and a BMI < 17 kg/m² had posttransplant survival rates comparable to those of other groups frequently undergoing transplantation. BMI < 17 kg/m² as a single risk factor in the CF population should not be treated as an absolute contraindication to LTx.

Targeting the IL-22/IL-22BP axis enhances tight junctions and reduces inflammation during influenza infection

The seasonal burden of influenza coupled with the pandemic outbreaks of more pathogenic strains underscore a critical need to understand the pathophysiology of influenza injury in the lung. Interleukin-22 (IL-22) is a promising cytokine that is critical in protecting the lung during infection. This cytokine is strongly regulated by the soluble receptor IL-22-binding protein (IL-22BP), which is constitutively expressed in the lungs where it inhibits IL-22 activity. The IL-22/IL-22BP axis is thought to prevent chronic exposure of epithelial cells to IL-22. However, the importance of this axis is not understood during an infection such as influenza. Here we demonstrate through the use of IL-22BP-knockout mice (il-22ra2-/-) that a pro-IL-22 environment reduces pulmonary inflammation during H1N1 (PR8/34 H1N1) infection and protects the lung by promoting tight junction formation. We confirmed these results in normal human bronchial epithelial cells in vitro demonstrating improved membrane resistance and induction of the tight junction proteins Cldn4, Tjp1, and Tjp2. Importantly, we show that administering recombinant IL-22 in vivo reduces inflammation and fluid leak into the lung. Taken together, our results demonstrate the IL-22/IL-22BP axis is a potential targetable pathway for reducing influenza-induced pneumonia.

Organ Transplantation for Cystic Fibrosis

Cystic fibrosis (CF) remains the most common indication for lung transplantation in children and the third most common in adults and has the highest median survival posttransplant for all pretransplant diagnoses. Criteria for transplant in patients with CF vary widely among transplant centers and early referral to multiple centers may be needed to maximize opportunities for lung transplantation. Comorbidities unique to CF such as resistant and atypical pathogens like Burkholderia and Mycobacterium abscessus, and cirrhosis require special consideration for lung transplantation but should not be considered as absolute contraindications. For those patients who are listed for lung transplantation, mechanical support with extracorporeal membrane oxygenation and mechanical ventilation can be efficacious as bridges to lung transplantation in experienced centers with adequate resources. Liver and pancreas transplantations are also acceptable options for end-organ disease related to CF and can provide improvements in both quantity and quality of life.

Insulin-like growth factor (IGF)-II- mediated fibrosis in pathogenic lung conditions

Type 2 insulin-like growth factor (IGF-II) levels are increased in fibrosing lung diseases such as idiopathic pulmonary fibrosis (IPF) and scleroderma/systemic sclerosis-associated pulmonary fibrosis (SSc). Our goal was to investigate the contribution of IGF receptors to IGF-II-mediated fibrosis in these diseases and identify other potential mechanisms key to the fibrotic process. Cognate receptor gene and protein expression were analyzed with qRT-PCR and immunoblot in primary fibroblasts derived from lung tissues of normal donors (NL) and patients with IPF or SSc. Compared to NL, steady-state receptor gene expression was decreased in SSc but not in IPF. IGF-II stimulation differentially decreased receptor mRNA and protein levels in NL, IPF, and SSc fibroblasts. Neutralizing antibody, siRNA, and receptor inhibition targeting endogenous IGF-II and its primary receptors, type 1 IGF receptor (IGF1R), IGF2R, and insulin receptor (IR) resulted in loss of the IGF-II response. IGF-II tipped the TIMP:MMP balance, promoting a fibrotic environment both intracellularly and extracellularly. Differentiation of fibroblasts into myofibroblasts by IGF-II was blocked with a TGFβ1 receptor inhibitor. IGF-II also increased TGFβ2 and TGFβ3 expression, with subsequent activation of canonical SMAD2/3 signaling. Therefore, IGF-II promoted fibrosis through IGF1R, IR, and IGF1R/IR, differentiated fibroblasts into myofibroblasts, decreased protease production and extracellular matrix degradation, and stimulated expression of two TGFβ isoforms, suggesting that IGF-II exerts pro-fibrotic effects via multiple mechanisms.

Routine deep vein thrombosis screening after lung transplantation: Incidence and risk factors

BACKGROUND

Deep vein thrombosis (DVT) remains a common complication following lung transplantation despite universal routine DVT screening. Moreover, many of the previously reported risk factors are incompletely defined. We sought to explore the influence of DVT screening and to more definitively assess predisposing risk factors.

METHODS

A single-institution, retrospective, cohort study of 1141 patients undergoing lung transplantation from January 1, 2005, to December 31, 2014, was performed evaluating for the rate of DVT. Patients were given prophylactic subcutaneous heparin postoperatively. DVT events were noted if they occurred before 90 days after transplant. We compared DVT rates before and after 2008 when universal screening was implemented. We also evaluated the timing of DVT event and location (above the knee vs below the knee). DVTs were treated with standard anticoagulation therapy or an inferior cava filter when patients were unable to tolerate anticoagulation treatment. Univariable and multivariable models were used to identify risk factors for occurrence. A propensity match was performed to match groups across the eras, and a Cox regression was performed to identify differences in 1-year survival trajectory between cohorts.

RESULTS

The rates of DVT before and after routine screening were 8.8% (36 DVT out of 412 transplants) and 17.3% (126 out of 729 transplants), respectively. These 2 rates were significantly different (P < .01); moreover, the observed DVT incidence per year was not significantly different across the 6 years after universal DVT screening was implemented (P > .90 for all comparisons). Observed DVT incidence at day 0 and day 14 were 3.8% and 3.8%, respectively, for the cohort before DVT protocols were established. Observed DVT incidence for the cohort after protocols were established at the same time points was 8.7% and 3.7%, respectively. Univariable analysis revealed that significant factors associated with a DVT include hypercholesterolemia (odds ratio [OR], 6.90; 95% confidence interval [CI], 1.82-26.13; P < .01), the number of days in the intensive care unit (OR, 1.03; 95% CI, 1.00-1.01; P < .01), and the length of stay in the hospital (OR, 1.01; 95% CI, 1.01-1.02; P < .01), whereas having quit smoking (vs never smoked) was associated with a decrease in DVT development (OR, 0.50; 95% CI, 0.33-0.75; P < .01). Multivariable analysis revealed 2 significant variables: hypercholesterolemia (OR, 8.13; 95% CI, 1.22-54.37; P = .03) and length of stay (OR, 1.03; 95% CI, 1.01-1.05; P < .01). There was a trend for better 1-year survival in the post-2008 era (Exp[β], 1.49; P = .09).

CONCLUSIONS

The rate of DVT diagnosis significantly increased after universal DVT screening was implemented. Furthermore, those patients undergoing lung transplantation with extended length of stay and hypercholesterolemia were prone to increased rates of DVT. There was a trend toward better 1-year survival in DVT-screened patients, suggesting DVT screening may result in beneficial outcomes.

Multiprobe Nuclear Imaging of the Cystic Fibrosis Lung as a Biomarker of Therapeutic Effect

Background: Nuclear imaging biomarkers illustrate unique aspects of lung physiology and are useful for assessing therapeutic effects in cystic fibrosis (CF) lung disease. We have developed a multiprobe method to simultaneously measure mucociliary clearance (MCC) and paracellular absorption (ABS). MCC is a direct measure of mucus clearance. ABS has been related to airway surface liquid (ASL) absorption through previous in vitro studies. Methods: We describe baseline factors affecting MCC and ABS using data from a retrospective baseline group (n = 22) and the response of the measures to inhaled 7% hypertonic saline (HS) and dry powder mannitol using data from a prospective response group (n = 7). A retrospective healthy control group (n = 15) is also described. The baseline and control groups performed single measurements of MCC/ABS. The response group performed baseline measurements of MCC/ABS and measurements after each intervention. Results: ABS was correlated (Spearman's ρ = 0.51, p = 0.06) to sweat chloride, a systemic measure of cystic fibrosis transmembrane conductance regulator (CFTR) function, whereas MCC was not. Baseline MCC was depressed after Pseudomonas aeruginosa infection as we have previously described. MCC provided a more sensitive indication of therapeutic effect and indicated improved clearance with mannitol compared with HS. Conclusion: MCC provides a useful and well-established means of testing therapies directed at improving mucus clearance in the lung. ABS may provide a means of detecting local changes in ASL absorption and CFTR function in the lung. Both are useful tools for studying the key aspects of CF lung pathophysiology (ASL hyperabsorption and MCC depression) that link the basic genetic defects of CF to disease manifestations in the lung.

Outcomes in Lung Transplant Recipients With Mycobacterium abscessus Infection: A 15-Year Experience From a Large Tertiary Care Center

BACKGROUND

Mycobacterium abscessus (M abscessus) infection is a serious complication post-lung transplant (LTx). We examined determinants of outcomes in LTx recipients infected with M abscessus.

METHODS

Electronic records of all patients who underwent LTx in a single transplant center between 2000 and 2015 were screened for isolation of M abscessus before or after LTx.

RESULTS

Twenty-six cases of M abscessus isolation were identified. Twenty-four had M abscessus isolation post-LTx. Two had M abscessus isolated from a surgical site, while the others were pulmonary isolates. Out of these 22 with pulmonary isolates, 12 had clinical disease. In 73% of patients, treatment had to be temporarily held or switched due to intolerance and toxicity. There was a statistically significant worsening in survival in those who developed clinical disease compared to matched controls. Among the 12 patients with clinical pulmonary disease, use of clofazimine was significantly associated with a favorable outcome. Six patients had M abscessus isolation pretransplant. Four developed M abscessus recurrence at a median of 2 months post-LTx. Two recurrences were surgical site infections, and 2 were pulmonary infections.

CONCLUSION

M abscessus infection is difficult to treat as tolerance to medications used is poor. M abscessus pneumonia is associated with worse survival post-LTx. Use of clofazimine is associated with 1-year infection-free survival.