Antigen stasis and airway nitrosative stress in human primary ciliary dyskinesia.

Nasal nitric oxide (nNO) is low in most patients with primary ciliary dyskinesia (PCD). Decreased ciliary motion could lead to antigen stasis, increasing oxidant production and NO oxidation in the airways. This could both decrease gas phase NO and increase nitrosative stress. We studied primary airway epithelial cells from healthy controls (HCs) and patients with PCD with several different genotypes. We measured antigen clearance in fenestrated membranes exposed apically to the fluorescently labeled antigen Dermatophagoides pteronyssinus (Derp1-f). We immunoblotted for 3-nitrotyrosine (3-NT) and for oxidative response enzymes. We measured headspace NO above primary airway cells without and with a PCD-causing genotype. We measured nNO and exhaled breath condensate (EBC) H2O2 in vivo. Apical Derp1-f was cleared from HC better than from PCD cells. DUOX1 expression was lower in HC than in PCD cells at baseline and after 24-h Derp1-f exposure. HC cells had less 3-NT and NO3- than PCD cells. However, NO consumption by HC cells was less than that by PCD cells; NO loss was prevented by superoxide dismutase (SOD) and by apocynin. nNO was higher in HCs than in patients with PCD. EBC H2O2 was lower in HC than in patients with PCD. The PCD airway epithelium does not optimally clear antigens and is subject to oxidative and nitrosative stress. Oxidation associated with antigen stasis could represent a therapeutic target in PCD, one with convenient monitoring biomarkers.NEW & NOTEWORTHY The PCD airway epithelium does not optimally clear antigens, and antigen exposure can lead to NO oxidation and nitrosative stress. Oxidation caused by antigen stasis could represent a therapeutic target in PCD, and there are convenient monitoring biomarkers.

Efficacy and safety of CD24Fc in hospitalised patients with COVID-19: a randomised, double-blind, placebo-controlled, phase 3 study.

BACKGROUND: Non-antiviral therapeutic options are required for the treatment of hospitalised patients with COVID-19. CD24Fc is an immunomodulator with potential to reduce the exaggerated inflammatory response to tissue injuries. We aimed to evaluate the safety and efficacy of CD24Fc in hospitalised adults with COVID-19 receiving oxygen support. METHODS: We conducted a randomised, double-blind, placebo-controlled, phase 3 study at nine medical centres in the USA. Hospitalised patients (age ≥18 years) with confirmed SARS-CoV-2 infection who were receiving oxygen support and standard of care were randomly assigned (1:1) by site-stratified block randomisation to receive a single intravenous infusion of CD24Fc 480 mg or placebo. The study funder, investigators, and patients were masked to treatment group assignment. The primary endpoint was time to clinical improvement over 28 days, defined as time that elapsed between a baseline National Institute of Allergy and Infectious Diseases ordinal scale score of 2-4 and reaching a score of 5 or higher or hospital discharge. The prespecified primary interim analysis was done when 146 participants reached the time to clinical improvement endpoint. Efficacy was assessed in the intention-to-treat population. Safety was assessed in the as-treated population. This study is registered with ClinicalTrials.gov, NCT04317040. FINDINGS: Between April 24 and Sept 22, 2020, 243 hospitalised patients were assessed for eligibility and 234 were enrolled and randomly assigned to receive CD24Fc (n=116) or placebo (n=118). The prespecified interim analysis was done when 146 participants reached the time to clinical improvement endpoint among 197 randomised participants. In the interim analysis, the 28-day clinical improvement rate was 82% (81 of 99) for CD24Fc versus 66% (65 of 98) for placebo; median time to clinical improvement was 6·0 days (95% CI 5·0-8·0) in the CD24Fc group versus 10·0 days (7·0-15·0) in the placebo group (hazard ratio [HR] 1·61, 95% CI 1·16-2·23; log-rank p=0·0028, which crossed the prespecified efficacy boundary [α=0·0147]). 37 participants were randomly assigned after the interim analysis data cutoff date; among the 234 randomised participants, median time to clinical improvement was 6·0 days (95% CI 5·0-9·0) in the CD24Fc group versus 10·5 days (7·0-15·0) in the placebo group (HR 1·40, 95% CI 1·02-1·92; log-rank p=0·037). The proportion of participants with disease progression within 28 days was 19% (22 of 116) in the CD24Fc group versus 31% (36 of 118) in the placebo group (HR 0·56, 95% CI 0·33-0·95; unadjusted p=0·031). The incidences of adverse events and serious adverse events were similar in both groups. No treatment-related adverse events were observed. INTERPRETATION: CD24Fc is generally well tolerated and accelerates clinical improvement of hospitalised patients with COVID-19 who are receiving oxygen support. These data suggest that targeting inflammation in response to tissue injuries might provide a therapeutic option for patients hospitalised with COVID-19. FUNDING: Merck & Co, National Cancer Institute, OncoImmune.

Airway Thiol-NO Adducts as Determinants of Exhaled NO.

Thiol-NO adducts such as S-nitrosoglutathione (GSNO) are endogenous bronchodilators in human airways. Decreased airway S-nitrosothiol concentrations are associated with asthma. Nitric oxide (NO), a breakdown product of GSNO, is measured in exhaled breath as a biomarker in asthma; an elevated fraction of expired NO (FENO) is associated with asthmatic airway inflammation. We hypothesized that FENO could reflect airway S-nitrosothiol concentrations. To test this hypothesis, we first studied the relationship between mixed expired NO and airway S-nitrosothiols in patients endotracheally intubated for respiratory failure. The inverse (Lineweaver-Burke type) relationship suggested that expired NO could reflect the rate of pulmonary S-nitrosothiol breakdown. We thus studied NO evolution from the lungs of mice (GSNO reductase -/-) unable reductively to catabolize GSNO. More NO was produced from GSNO in the -/- compared to wild type lungs. Finally, we formally tested the hypothesis that airway GSNO increases FENO using an inhalational challenge model in normal human subjects. FENO increased in all subjects tested, with a median t1/2 of 32.0 min. Taken together, these data demonstrate that FENO reports, at least in part, GSNO breakdown in the lungs. Unlike GSNO, NO is not present in the lungs in physiologically relevant concentrations. However, FENO following a GSNO challenge could be a non-invasive test for airway GSNO catabolism.

Benefits of Airway Androgen Receptor Expression in Human Asthma.

Rationale: Androgens are potentially beneficial in asthma, but AR (androgen receptor) has not been studied in human airways.Objectives: To measure whether AR and its ligands are associated with human asthma outcomes.Methods: We compared the effects of AR expression on lung function, symptom scores, and fractional exhaled nitric oxide (FeNO) in adults enrolled in SARP (Severe Asthma Research Program). The impact of sex and of androgens on asthma outcomes was also evaluated in the SARP with validation studies in the Cleveland Clinic Health System and the NHANES (U.S. National Health and Nutrition Examination Survey).Measurements and Main Results: In SARP (n = 128), AR gene expression from bronchoscopic epithelial brushings was positively associated with both FEV1/FVC ratio (R2 = 0.135, P = 0.0002) and the total Asthma Quality of Life Questionnaire score (R2 = 0.056, P = 0.016) and was negatively associated with FeNO (R2 = 0.178, P = 9.8 × 10-6) and NOS2 (nitric oxide synthase gene) expression (R2 = 0.281, P = 1.2 × 10-10). In SARP (n = 1,659), the Cleveland Clinic Health System (n = 32,527), and the NHANES (n = 2,629), women had more asthma exacerbations and emergency department visits than men. The levels of the AR ligand precursor dehydroepiandrosterone sulfate correlated positively with the FEV1 in both women and men.Conclusions: Higher bronchial AR expression and higher androgen levels are associated with better lung function, fewer symptoms, and a lower FeNO in human asthma. The role of androgens should be considered in asthma management.

A Treatment to Eliminate SARS-CoV-2 Replication in Human Airway Epithelial Cells Is Safe for Inhalation as an Aerosol in Healthy Human Subjects.

BACKGROUND: Low airway surface pH is associated with many airway diseases, impairs antimicrobial host defense, and worsens airway inflammation. Inhaled Optate is designed to safely raise airway surface pH and is well tolerated in humans. Raising intracellular pH partially prevents activation of SARS-CoV-2 in primary normal human airway epithelial (NHAE) cells, decreasing viral replication by several mechanisms. METHODS: We grew primary NHAE cells from healthy subjects, infected them with SARS-CoV-2 (isolate USA-WA1/2020), and used clinical Optate at concentrations used in humans in vivo to determine whether Optate would prevent viral infection and replication. Cells were pretreated with Optate or placebo prior to infection (multiplicity of infection = 1), and viral replication was determined with plaque assay and nucleocapsid (N) protein levels. Healthy human subjects also inhaled Optate as part of a Phase 2a safety trial. RESULTS: Optate almost completely prevented viral replication at each time point between 24 h and 120 h, relative to placebo, on both plaque assay and N protein expression (P < .001). Mechanistically, Optate inhibited expression of major endosomal trafficking genes and raised NHAE intracellular pH. Optate had no effect on NHAE cell viability at any time point. Inhaled Optate was well tolerated in 10 normal subjects, with no change in lung function, vital signs, or oxygenation. CONCLUSIONS: Inhaled Optate may be well suited for a clinical trial in patients with pulmonary SARS-CoV-2 infection. However, it is vitally important for patient safety that formulations designed for inhalation with regard to pH, isotonicity, and osmolality be used. An inhalational treatment that safely prevents SARS-CoV-2 viral replication could be helpful for treating patients with pulmonary SARS-CoV-2 infection.

Mapping targetable inflammation and outcomes with cystic fibrosis biomarkers.

Cystic fibrosis is characterized by an overly exuberant neutrophilic inflammatory response to pathogens and other stimuli that starts very early in disease. The overwhelming nature of this response is a primary cause of remodeling and destruction of the airways, suggesting that anti-inflammatory therapies could be beneficial in CF. However, finding therapies that can effectively reduce the inflammatory response without compromising host defenses remains elusive. New approaches towards mapping inflammatory targets promise to aid in developing novel therapeutic strategies and improve outcomes in individuals with CF.

Outcomes associated with antibiotic regimens for treatment of Mycobacterium abscessus in cystic fibrosis patients.

BACKGROUND: Mycobacterium abscessus infection is associated with declining lung function in cystic fibrosis (CF), but there is little evidence on clinical efficacy to guide treatment. METHODS: Retrospective review of 37 CF patients treated for M. abscessus respiratory infection at a single center from 2006 to 2014. Outcomes included change in FEV1 at 30, 60, 90, 180, and 365days after treatment and clearance of M. abscessus from sputum cultures. RESULTS: Lung function was significantly improved after 30 and 60days of treatment, but not at later time points. Gains were inversely related to starting lung function. Antibiotic choices did not influence outcomes except for greater clearance with clarithromycin. CONCLUSIONS: Treatment of M. abscessus resulted in short term improvement in lung function that is inversely related to pre-treatment FEV1.

Emergence and spread of a human-transmissible multidrug-resistant nontuberculous mycobacterium.

Lung infections with Mycobacterium abscessus, a species of multidrug-resistant nontuberculous mycobacteria, are emerging as an important global threat to individuals with cystic fibrosis (CF), in whom M. abscessus accelerates inflammatory lung damage, leading to increased morbidity and mortality. Previously, M. abscessus was thought to be independently acquired by susceptible individuals from the environment. However, using whole-genome analysis of a global collection of clinical isolates, we show that the majority of M. abscessus infections are acquired through transmission, potentially via fomites and aerosols, of recently emerged dominant circulating clones that have spread globally. We demonstrate that these clones are associated with worse clinical outcomes, show increased virulence in cell-based and mouse infection models, and thus represent an urgent international infection challenge.

Endobronchial valve placement for the treatment of bronchopleural fistula: a review of the current literature.

PURPOSE OF REVIEW: Bronchopleural fistula is a cause of increased morbidity and mortality. Patients who develop bronchopleural fistula after lung resection or spontaneous pneumothorax often have multiple co-morbidities making them poor candidates for repeated surgical intervention. Previous nonsurgical treatments for bronchopleural fistula have had limited success. Endobronchial valves, originally designed for bronchoscopic lung volume reduction, have been used under a humanitarian use exception for the treatment of bronchopleural fistula. Numerous case series and reports have been published; however, guidelines for the use of endobronchial valves specifically for bronchopleural fistula have yet to be developed. RECENT FINDINGS: A number of case series and reports have described the use of one-way endobronchial valves for the treatment of bronchopleural fistula, after spontaneous pneumothorax, lung resection and complication of suppurative lung disease. In the largest series reported (40 patients), 93% of patients experienced improvement in air leak, with 48% having complete resolution. Other series have shown similar success. Complications are rare and include pneumonia, expectoration or migration of valves, and bacterial colonization. SUMMARY: The use of endobronchial valves for the treatment of bronchopleural fistula is well tolerated and effective. Controlled clinical trials are needed to further evaluate their efficacy and identify ideal patient populations for their use.

Importance of the CCR5-CCL5 axis for mucosal Trypanosoma cruzi protection and B cell activation.

Trypanosoma cruzi is an intracellular parasite and the causative agent of Chagas disease. Previous work has shown that the chemokine receptor CCR5 plays a role in systemic T. cruzi protection. We evaluated the importance of CCR5 and CCL5 for mucosal protection against natural oral and conjunctival T. cruzi challenges. T. cruzi-immune CCR5(-/-) and wild-type C57BL/6 mice were generated by repeated infectious challenges with T. cruzi. CCR5(-/-) and wild-type mice developed equivalent levels of cellular, humoral, and protective mucosal responses. However, CCR5(-/-)-immune mice produced increased levels of CCL5 in protected gastric tissues, suggesting compensatory signaling through additional receptors. Neutralization of CCL5 in CCR5(-/-)-immune mice resulted in decreased mucosal inflammatory responses, reduced T. cruzi-specific Ab-secreting cells, and significantly less mucosal T. cruzi protection, confirming an important role for CCL5 in optimal immune control of T. cruzi replication at the point of initial mucosal invasion. To investigate further the mechanism responsible for mucosal protection mediated by CCL5-CCR5 signaling, we evaluated the effects of CCL5 on B cells. CCL5 enhanced proliferation and IgM secretion in highly purified B cells triggered by suboptimal doses of LPS. In addition, neutralization of endogenous CCL5 inhibited B cell proliferation and IgM secretion during stimulation of highly purified B cells, indicating that B cell production of CCL5 has important autocrine effects. These findings demonstrate direct effects of CCL5 on B cells, with significant implications for the development of mucosal adjuvants, and further suggest that CCL5 may be important as a general B cell coactivator.

Immune responses to gp82 provide protection against mucosal Trypanosoma cruzi infection.

The potential use of the Trypanosoma cruzi metacyclic trypomastigote (MT) stage-specific molecule glycoprotein-82 (gp82) as a vaccine target has not been fully explored. We show that the opsonization of T. cruzi MT with gp82-specific antibody prior to mucosal challenge significantly reduces parasite infectivity. In addition, we investigated the immune responses as well as the systemic and mucosal protective immunity induced by intranasal CpG-adjuvanted gp82 vaccination. Spleen cells from mice immunized with CpG-gp82 proliferated and secreted IFN-γ in a dose-dependent manner in response to in vitro stimulation with gp82 and parasite lysate. More importantly, these CpG-gp82-immunized mice were significantly protected from a biologically relevant oral parasite challenge.

Immune responses to gp82 provide protection against mucosal Trypanosoma cruzi infection

The potential use of the Trypanosoma cruzi metacyclic trypomastigote (MT) stage-specific molecule glycoprotein-82 (gp82) as a vaccine target has not been fully explored. We show that the opsonization of T. cruzi MT with gp82-specific antibody prior to mucosal challenge significantly reduces parasite infectivity. In addition, we investigated the immune responses as well as the systemic and mucosal protective immunity induced by intranasal CpG-adjuvanted gp82 vaccination. Spleen cells from mice immunized with CpG-gp82 proliferated and secreted IFN-γ in a dose-dependent manner in response to in vitro stimulation with gp82 and parasite lysate. More importantly, these CpG-gp82-immunized mice were significantly protected from a biologically relevant oral parasite challenge.

Trans-sialidase recombinant protein mixed with CpG motif-containing oligodeoxynucleotide induces protective mucosal and systemic trypanosoma cruzi immunity involving CD8+ CTL and B cell-mediated cross-priming.

The Trypanosoma cruzi trans-sialidase (TS) is a unique enzyme with neuraminidase and sialic acid transfer activities important for parasite infectivity. The T. cruzi genome contains a large family of TS homologous genes, and it has been suggested that TS homologues provide a mechanism of immune escape important for chronic infection. We have investigated whether the consensus TS enzymatic domain could induce immunity protective against acute and chronic, as well as mucosal and systemic, T. cruzi infection. We have shown that: 1) TS-specific immunity can protect against acute T. cruzi infection; 2) effective TS-specific immunity is maintained during chronic T. cruzi infection despite the expression of numerous related TS superfamily genes encoding altered peptide ligands that in theory could promote immune tolerization; and 3) the practical intranasal delivery of recombinant TS protein combined with a ssDNA oligodeoxynucleotide (ODN) adjuvant containing unmethylated CpG motifs can induce both mucosal and systemic protective immunity. We have further demonstrated that the intranasal delivery of soluble TS recombinant Ag combined with CpG ODN induces both TS-specific CD4(+) and CD8(+) T cells associated with vaccine-induced protective immunity. In addition, optimal protection induced by intranasal TS Ag combined with CpG ODN requires B cells, which, after treatment with CpG ODN, have the ability to induce TS-specific CD8(+) T cell cross-priming. Our results support the development of TS vaccines for human use, suggest surrogate markers for use in future human vaccine trials, and mechanistically identify B cells as important APC targets for vaccines designed to induce CD8(+) CTL responses.