Inhaled Molgramostim Therapy in Autoimmune Pulmonary Alveolar Proteinosis

Extracellular vesicles from alveolar macrophages harboring phagocytosed methicillin-resistant Staphylococcus aureus induce necroptosis

Methicillin-resistant Staphylococcus aureus (MRSA) infection, a major cause of hospital- and community-acquired pneumonia, still has a high mortality rate. Extracellular vesicles (EVs), as crucial mediators of intercellular communication, have a significant impact on infectious diseases. However, the role of EVs from alveolar macrophages (AMs) in MRSA pneumonia remains unclear. We report that AMs phagocytose MRSA and release more EVs in mice with MRSA pneumonia. EVs from AMs harboring phagocytosed MRSA exhibit significant proinflammatory effects and induce necroptosis by delivering tumor necrosis factor α (TNF-α) and miR-146a-5p. Mechanically, the upregulated miR-146a-5p in these EVs enhances the phosphorylation of RIPK1, RIPK3, and MLKL by targeting TNF receptor-associated factor 6 (TRAF6), thereby promoting TNF-α-induced necroptosis. The combination of a TNF-α antagonist and an miR-146a-5p antagomir effectively improves the outcomes of mice with MRSA pneumonia. Overall, we reveal the pronecrotic effect of EVs from MRSA-infected AMs and provide a promising target for the prevention and treatment of MRSA pneumonia.

Pathogenesis-driven treatment of primary pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a syndrome that results from the accumulation of lipoproteinaceous material in the alveolar space. According to the underlying pathogenetic mechanisms, three different forms have been identified, namely primary, secondary and congenital. Primary PAP is caused by disruption of granulocyte-macrophage colony-stimulating factor (GM-CSF) signalling due to the presence of neutralising autoantibodies (autoimmune PAP) or GM-CSF receptor genetic defects (hereditary PAP), which results in dysfunctional alveolar macrophages with reduced phagocytic clearance of particles, cholesterol and surfactant. The serum level of GM-CSF autoantibody is the only disease-specific biomarker of autoimmune PAP, although it does not correlate with disease severity. In PAP patients with normal serum GM-CSF autoantibody levels, elevated serum GM-CSF levels is highly suspicious for hereditary PAP. Several biomarkers have been correlated with disease severity, although they are not specific for PAP. These include lactate dehydrogenase, cytokeratin 19 fragment 21.1, carcinoembryonic antigen, neuron-specific enolase, surfactant proteins, Krebs von Lungen 6, chitinase-3-like protein 1 and monocyte chemotactic proteins. Finally, increased awareness of the disease mechanisms has led to the development of pathogenesis-based treatments, such as GM-CSF augmentation and cholesterol-targeting therapies.

OPTIMA: An Open-Label, Noncomparative Pilot Trial of Inhaled Molgramostim in Pulmonary Nontuberculous Mycobacterial Infection

Rationale: Inhaled granulocyte-macrophage colony-stimulating factor (GM-CSF) has been proposed as a potential immunomodulatory treatment for nontuberculous mycobacterial (NTM) infection.Objectives: This open-label, noncomparative pilot trial investigated the efficacy and safety of inhaled GM-CSF (molgramostim nebulizer solution) in patients with predominantly treatment-refractory pulmonary NTM infection (Mycobacterium avium complex [MAC] and M. abscessus [MABS]), either in combination with ongoing guideline-based therapy (GBT) or as monotherapy in patients who had stopped GBT because of lack of efficacy or intolerability.Methods: Thirty-two adult patients with refractory NTM infection (MAC, n = 24; MABS, n = 8) were recruited into two cohorts: those with (n = 16) and without (n = 16) ongoing GBT. Nebulized molgramostim 300 μg/d was administered over 48 weeks. Sputum cultures and smears and clinical assessments (6-min-walk distance, symptom scores, Quality of Life-Bronchiectasis Questionnaire score, and body weight) were collected every 4 weeks during treatment and 12 weeks after the end of treatment. The primary endpoint was sputum culture conversion, defined as three consecutive monthly negative cultures during the treatment period.Results: Eight patients (25%) achieved culture conversion on treatment (seven [29.2%] patients with MAC infection, one [12.5%] patient with MABS infection); in four patients, this was durable after the end of treatment. Of the 24 patients with MAC infection, an additional 4 patients had a partial response, converting from smear positive at baseline to smear negative at the end of treatment, and time to positivity in liquid culture media increased. Two of these patients sustained negative cultures from the end of treatment. Other clinical endpoints were unchanged. Serious adverse events were mainly pulmonary exacerbations or worsening NTM infection. Three deaths, not treatment related, were reported.Conclusions: In this population of patients with severe NTM disease, molgramostim was safe and well tolerated. Sputum culture conversion rates for patients with MAC infection (29.2%) were greater than reported for similar refractory MAC cohorts managed with GBT alone. Less benefit was seen for MABS infection. No serious safety concerns were identified. Further evaluation in a larger cohort is warranted.Clinical trial registered with www.clinicaltrials.gov (NCT03421743).

Anti-cytokine autoantibodies: mechanistic insights and disease associations

Anti-cytokine autoantibodies (ACAAs) are increasingly recognized as modulating disease severity in infection, inflammation and autoimmunity. By reducing or augmenting cytokine signalling pathways or by altering the half-life of cytokines in the circulation, ACAAs can be either pathogenic or disease ameliorating. The origins of ACAAs remain unclear. Here, we focus on the most common ACAAs in the context of disease groups with similar characteristics. We review the emerging genetic and environmental factors that are thought to drive their production. We also describe how the profiling of ACAAs should be considered for the early diagnosis, active monitoring, treatment or sub-phenotyping of diseases. Finally, we discuss how understanding the biology of naturally occurring ACAAs can guide therapeutic strategies.

Pulmonary Alveolar Proteinosis and new therapeutic concepts

Pulmonary alveolar proteinosis (PAP) is an umbrella term used to refer to a pulmonary syndrome which is characterized by excessive accumulation of surfactant in the lungs of affected individuals. In general, PAP is a rare lung disease affecting children and adults, although its prevalence and incidence is variable among different countries. Even though PAP is a rare disease, it is a prime example on how modern medicine can lead to new therapeutic concepts, changing ways and techniques of (genetic) diagnosis which ultimately led into personalized treatments, all dedicated to improve the function of the impaired lung and thus life expectancy and quality of life in PAP patients. In fact, new technologies, such as new sequencing technologies, gene therapy approaches, new kind and sources of stem cells and completely new insights into the ontogeny of immune cells such as macrophages have increased our understanding in the onset and progression of PAP, which have paved the way for novel therapeutic concepts for PAP and beyond. As of today, classical monocyte-derived macrophages are known as important immune mediator and immune sentinels within the innate immunity. Furthermore, macrophages (known as tissue resident macrophages (TRMs)) can also be found in various tissues, introducing e. g. alveolar macrophages in the broncho-alveolar space as crucial cellular determinants in the onset of PAP and other lung disorders. Given recent insights into the onset of alveolar macrophages and knowledge about factors which impede their function, has led to the development of new therapies, which are applied in the context of PAP, with promising implications also for other diseases in which macrophages play an important role. Thus, we here summarize the latest insights into the various forms of PAP and introduce new pre-clinical work which is currently conducted in the framework of PAP, introducing new therapies for children and adults who still suffer from this severe, potentially life-threatening disease.

Clinical efficacy of rhGM-CSF gel and medical collagen sponge on deep second-degree burns of infants: A randomized clinical trial

BACKGROUND

This study aimed to observe clinical efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) gel, medical collagen sponge and rhGM-CSF gel in combination with medical collagen sponge on deep second-degree burns of head, face or neck in infants.

METHODS

A total of 108 infants with deep second-degree burns on head, face or neck were randomly divided into rhGM-CSF group, medical collagen sponge group, and rhGM-CSF + medical collagen sponge group. The scab dissolving time, healing time, bacterial positive rate and Vancouver scar scale were evaluated and analyzed.

RESULTS

The data analysis showed that scab dissolving time and healing time were shorter in rhGM-CSF + medical collagen sponge group than that in rhGM-CSF group and medical collagen sponge group, and the difference was statistically significant (P < .05). Bacterial positive rate was lower in rhGM-CSF + medical collagen sponge group than that in rhGM-CSF group and medical collagen sponge group (P < .05). After 3 months, score of Vancouver scar scale (scar thickness, pliability, pigmentation and vascularity) was less in rhGM-CSF + medical collagen sponge group than that in rhGM-CSF group and medical collagen sponge group (P < .05).

CONCLUSION

rhGM-CSF gel in combination with medical collagen sponge is significantly effective in treating deep second-degree burns of head, face or neck in infants. This combination is beneficial for infection control, acceleration of scab dissolving and wound healing, and reduction of scar hyperplasia and pigmentation, which is worthy of clinical application and promotion.

Inhaled recombinant GM-CSF reduces the need for whole lung lavage and improves gas exchange in autoimmune pulmonary alveolar proteinosis patients

RATIONALE

Whole lung lavage (WLL) is a widely accepted palliative treatment for autoimmune pulmonary alveolar proteinosis (aPAP) but does not correct myeloid cell dysfunction or reverse the pathological accumulation of surfactant. In contrast, inhaled recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) is a promising pharmacological approach that restores alveolar macrophage functions including surfactant clearance. Here, we evaluate WLL followed by inhaled rGM-CSF (sargramostim) as therapy of aPAP.

METHODS

18 patients with moderate-to-severe aPAP were enrolled, received baseline WLL, were randomised into either the rGM-CSF group (receiving inhaled sargramostim) or control group (no scheduled therapy) and followed for 30 months after the baseline WLL. Outcome measures included additional unscheduled "rescue" WLL for disease progression, assessment of arterial blood gases, pulmonary function, computed tomography, health status, biomarkers and adverse events. Patients requiring rescue WLL were considered to have failed their assigned intervention group.

RESULTS

The primary end-point of time to first rescue WLL was longer in rGM-CSF-treated patients than controls (30 versus 18 months, n=9 per group, p=0.0078). Seven control patients (78%) and only one rGM-CSF-treated patient (11%) required rescue WLL, demonstrating a 7-fold increase in relative risk (p=0.015). Compared to controls, rGM-CSF-treated patients also had greater improvement in peripheral arterial oxygen tension, alveolar-arterial oxygen tension difference, diffusing capacity of the lungs for carbon monoxide and aPAP biomarkers. One patient from each group withdrew for personal reasons. No serious adverse events were reported.

CONCLUSIONS

This long-term, prospective, randomised trial demonstrated inhaled sargramostim following WLL reduced the requirement for WLL, improved lung function and was safe in aPAP patients. WLL plus inhaled sargramostim may be useful as combined therapy for aPAP.

Emerging Treatments for Childhood Interstitial Lung Disease

Childhood interstitial lung disease (chILD) is a large and heterogeneous group of disorders characterized by diffuse lung parenchymal markings on chest imaging and clinical signs such as dyspnea and hypoxemia from functional impairment. While some children already present in the neonatal period with interstitial lung disease (ILD), others develop ILD during their childhood and adolescence. A timely and accurate diagnosis is essential to gauge treatment and improve prognosis. Supportive care can reduce symptoms and positively influence patients' quality of life; however, there is no cure for many of the chILDs. Current therapeutic options include anti-inflammatory or immunosuppressive drugs. Due to the rarity of the conditions and paucity of research in this field, most treatments are empirical and based on case series, and less than a handful of small, randomized trials have been conducted thus far. A trial on hydroxychloroquine yielded good safety but a much smaller effect size than anticipated. A trial in fibrotic disease with the multitargeted tyrosine kinase inhibitor nintedanib showed similar pharmacokinetics and safety as in adults. The unmet need for the treatment of chILDs remains high. This article summarizes current treatments and explores potential therapeutic options for patients suffering from chILD.

Nebulised granulocyte-macrophage colony-stimulating factor (GM-CSF) in autoimmune pulmonary alveolar proteinosis: a systematic review and meta-analysis

BACKGROUND

Autoimmune pulmonary alveolar proteinosis (aPAP) results from impaired macrophage-mediated clearance of alveolar surfactant lipoproteins. Whole lung lavage has been the first-line treatment but recent reports suggest the efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF). We aimed to review the efficacy and safety of nebulised GM-CSF in aPAP.

METHODS

We conducted a systematic review and meta-analysis searching Embase, CINAHL, MEDLINE and Cochrane Collaborative databases (1946-1 April 2022). Studies included patients aged >18 years with aPAP receiving nebulised GM-CSF treatment and a comparator cohort. Exclusion criteria included secondary or congenital pulmonary alveolar proteinosis, GM-CSF allergy, active infection or other serious medical conditions. The protocol was prospectively registered with PROSPERO (CRD42021231328). Outcomes assessed were St George's Respiratory Questionnaire (SGRQ), 6-min walk test (6MWT), gas exchange (diffusing capacity of the lung for carbon monoxide (D LCO) % predicted) and arterial-alveolar oxygen gradient.

RESULTS

Six studies were identified for review and three for meta-analysis, revealing that SGRQ score (mean difference -8.09, 95% CI -11.88- -4.3, p<0.0001), functional capacity (6MWT) (mean difference 21.72 m, 95% CI -2.76-46.19 m, p=0.08), gas diffusion (D LCO % predicted) (mean difference 5.09%, 95% CI 2.05-8.13%, p=0.001) and arterial-alveolar oxygen gradient (mean difference -4.36 mmHg, 95% CI -7.19- -1.52 mmHg, p=0.003) all significantly improved in GM-CSF-treated patients with minor statistical heterogeneity (I2=0%). No serious trial-related adverse events were reported.

CONCLUSIONS

Patients with aPAP treated with inhaled GM-CSF demonstrated significant improvements in symptoms, dyspnoea scores, lung function, gas exchange and radiology indices after treatment with nebulised GM-CSF of varying duration. There is an important need to review comparative effectiveness and patient choice in key clinical outcomes between the current standard of care, whole lung lavage, with the noninvasive treatment of nebulised GM-CSF in aPAP.

Diagnosis and Management of the Systemic Juvenile Idiopathic Arthritis Patient with Emerging Lung Disease

Chronic lung disease in children with systemic juvenile idiopathic arthritis (SJIA-LD) is an emerging and potentially life-threatening disease complication. Despite recent descriptions of its clinical spectrum, preliminary immunologic characterization, and proposed hypotheses regaarding etiology, optimal approaches to diagnosis and management remain unclear. Here, we review the current clinical understanding of SJIA-LD, including the potential role of biologic therapy in disease pathogenesis, as well as the possibility of drug reactions with eosinophilia and systemic symptoms (DRESS). We discuss approaches to evaluation of children with suspected SJIA-LD, including a proposed algorithm to risk-stratify all SJIA patients for screening to detect LD early. We review potential pharmacologic and non-pharmacologic treatment approaches that have been reported for SJIA-LD or utilized in interstitial lung diseases associated with other rheumatic diseases. This includes lymphocyte-targeting therapies, JAK inhibitors, and emerging therapies against IL-18 and IFNγ. Finally, we consider urgent unmet needs in this area including in basic discovery of disease mechanisms and clinical research to improve disease detection and patient outcomes.

Autoimmune Pulmonary Alveolar Proteinosis That Improved after a COVID-19 Episode

Autoimmune pulmonary alveolar proteinosis (APAP) is caused by macrophage dysfunction owing to the presence of anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies. A 77-year-old man with APAP was referred to our hospital for whole-lung lavage (WLL) due to oxygenation exacerbation and pulmonary shadows. The patient had had coronavirus disease 2019 (COVID-19) during the APAP evaluation before WLL. About three months after COVID-19 resolved, his oxygenation and shadow reflecting APAP had obviously improved, thus avoiding the need for WLL. We suspected that the improvement in APAP was due to various immunological reactions induced by COVID-19.

Treatable traits: a comprehensive precision medicine approach in interstitial lung disease

Interstitial lung disease (ILD) is a diverse group of inflammatory and fibrotic lung conditions causing significant morbidity and mortality. A multitude of factors beyond the lungs influence symptoms, health-related quality of life, disease progression and survival in patients with ILD. Despite an increasing emphasis on multidisciplinary management in ILD, the absence of a framework for assessment and delivery of comprehensive patient care poses challenges in clinical practice. The treatable traits approach is a precision medicine care model that operates on the premise of individualised multidimensional assessment for distinct traits that can be targeted by specific interventions. The potential utility of this approach has been described in airway diseases, but has not been adequately considered in ILD. Given the similar disease heterogeneity and complexity between ILD and airway diseases, we explore the concept and potential application of the treatable traits approach in ILD. A framework of aetiological, pulmonary, extrapulmonary and behavioural and lifestyle treatable traits relevant to clinical care and outcomes for patients with ILD is proposed. We further describe key research directions to evaluate the application of the treatable traits approach towards advancing patient care and health outcomes in ILD.

Is it time to include oxygen needs as an endpoint in clinical trials in patients with fibrosing interstitial lung disease? If so, how?

Many patients with fibrosing interstitial lung disease (fILD) will need to use supplemental oxygen (O2) to maintain normoxia at some point in their illness. If it is not needed at the time of diagnosis, then if fILD progresses-or if a comorbid condition like pulmonary hypertension develops-O2 will become necessary, often, initially, during exertion and all-too-often, eventually, at rest as well. But presumably, if all else remains stable, if fILD progression is halted or slowed, O2 needs follow in parallel. Despite perceived or unnoticed benefits of O2, and prescribers' good intentions to improve patients' sense of well-being, patients with fILD generally view O2 with frustration and fear, as it threatens their already-impaired quality of life. Because of how meaningful and impactful O2 is to the lives of patients with fILD, 'O2 need' is a critically important-and perhaps the most-patient-centred metric that should be considered for incorporation as an endpoint in therapeutic trials. It is unclear how this should be done, but in this paper, we offer some possible approaches that merit consideration.

Alveolar macrophages in pulmonary alveolar proteinosis: origin, function, and therapeutic strategies

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disorder that is characterized by the abnormal accumulation of surfactant within the alveoli. Alveolar macrophages (AMs) have been identified as playing a pivotal role in the pathogenesis of PAP. In most of PAP cases, the disease is triggered by impaired cholesterol clearance in AMs that depend on granulocyte-macrophage colony-stimulating factor (GM-CSF), resulting in defective alveolar surfactant clearance and disruption of pulmonary homeostasis. Currently, novel pathogenesis-based therapies are being developed that target the GM-CSF signaling, cholesterol homeostasis, and immune modulation of AMs. In this review, we summarize the origin and functional role of AMs in PAP, as well as the latest therapeutic strategies aimed at addressing this disease. Our goal is to provide new perspectives and insights into the pathogenesis of PAP, and thereby identify promising new treatments for this disease.

Nationwide survey of adult patients with pulmonary alveolar proteinosis using the National Database of designated intractable diseases of Japan

BACKGROUND

Autoimmune pulmonary alveolar proteinosis (APAP) and congenital/hereditary PAP were labeled intractable diseases in Japan in 2015. Since then, patients registered in the National Database of Designated Incurable Diseases (NDDID) who met certain requirements became eligible for medical subsidies. Epidemiological studies using recent data are needed for the development of management protocols for patients with PAP.

METHODS

We conducted the first nationwide study describing the epidemiology and characteristics of PAP using data for patients registered in the Japanese NDDID between 2015 and 2020. We focused on patient demographics, diagnosis, disease severity score (DSS), symptoms, test results, and treatment.

RESULTS

We identified 110 patients with PAP, among whom 96.4% had APAP/idiopathic PAP (IPAP). The median age was 58 years, with a slight male predominance. Most patients had a DSS ≥3 (64.5%) and reported symptoms (e.g., dyspnea on exertion). High-resolution computed tomography typically revealed ground glass opacity and crazy paving appearances. Pulmonary function was relatively preserved, except for carbon monoxide diffusing capacity. Only 27.4% of patients underwent therapeutic whole-lung lavage and/or bronchoalveolar lavage, while 25% required long-term oxygen therapy. Serum Krebs von den Lungen-6, surfactant protein D, and lactate dehydrogenase levels significantly and positively correlated with the DSS.

CONCLUSIONS

Most patients registered in the NDDID have APAP/IPAP with a DSS ≥3, and about one-quarter require long-term oxygen therapy and infrequent lavages. Our results provide important details of the current prevalence and clinical practice related to APAP/IPAP with a DSS ≥3 in Japan.

The world of rare interstitial lung diseases

The world of rare interstitial lung diseases (ILDs) is diverse and complex. Diagnosis and therapy usually pose challenges. This review describes a selection of rare and ultrarare ILDs including pulmonary alveolar proteinosis, pulmonary alveolar microlithiasis and pleuroparenchymal fibroelastosis. In addition, monogenic ILDs or ILDs in congenital syndromes and various multiple cystic lung diseases will be discussed. All these conditions are part of the scope of the European Reference Network on rare respiratory diseases (ERN-LUNG). Epidemiology, pathogenesis, diagnostics and treatment of each disease are presented.

Updated severity and prognosis score of pulmonary alveolar proteinosis: A multi-center cohort study in China

Background

The high-resolution computed tomography (HRCT) score is an important component of the severity and prognosis score of pulmonary alveolar proteinosis (SPSP). However, the HRCT score in SPSP only considers the extent of opacity, which is insufficient.

Methods

We retrospectively evaluated HRCT scores for 231 patients with autoimmune pulmonary alveolar proteinosis (APAP) from three centers of the China Alliance for Rare Diseases. The SPSPII was created based on the overall density and extent, incorporating the SPSP. The severity of APAP patients was assessed using disease severity scores (DSS), SPSP, and SPSPII to determine the strengths and weaknesses of the different assessment methods. We then prospectively applied the SPSPII to patients before treatment, and the curative effect was assessed after 3 months.

Results

The HRCT overall density and extent scores in our retrospective analysis were higher than the extent scores in all patients and every original extent score severity group, as well as higher related to arterial partial oxygen pressure (PaO₂) than extent scores. The mild patients accounted for 61.9% based on DSS 1-2, 20.3% based on SPSP 1-3, and 20.8% based on SPSPII 1-3. Based on SPSP or SPSPII, the number of severe patients deteriorating was higher in the mild and moderate groups. When applied prospectively, arterial PaO₂ differed between any two SPSPII severity groups. The alveolar-arterial gradient in PaO₂ (P[A-a]O₂), % predicted carbon monoxide diffusing capacity of the lung (DLCO), and HRCT score were higher in the severe group than in the mild and moderate groups. After diagnosis, mild patients received symptomatic treatment, moderate patients received pure whole lung lavage (WLL) or granulocyte-macrophage colony-stimulating factor (GM-CSF) therapy, and severe patients received WLL and GM-CSF therapy. Importantly, the SPSPII in mild and severe groups were lower than baseline after 3 months.

Conclusion

The HRCT density and extent scores of patients with APAP were better than the extent score. The SPSPII score system based on smoking status, symptoms, PaO₂, predicted DLCO, and overall HRCT score was better than DSS and SPSP for assessing the severity and efficacy and predicting the prognosis.

Trial registration

ClinicalTrial.gov, identifier: NCT04516577.

Recombinant GM-CSF for diseases of GM-CSF insufficiency: Correcting dysfunctional mononuclear phagocyte disorders

Introduction

Endogenous granulocyte-macrophage colony-stimulating factor (GM-CSF), identified by its ability to support differentiation of hematopoietic cells into several types of myeloid cells, is now known to support maturation and maintain the metabolic capacity of mononuclear phagocytes including monocytes, macrophages, and dendritic cells. These cells sense and attack potential pathogens, present antigens to adaptive immune cells, and recruit other immune cells. Recombinant human (rhu) GM-CSF (e.g., sargramostim [glycosylated, yeast-derived rhu GM-CSF]) has immune modulating properties and can restore the normal function of mononuclear phagocytes rendered dysfunctional by deficient or insufficient endogenous GM-CSF.

Methods

We reviewed the emerging biologic and cellular effects of GM-CSF. Experts in clinical disease areas caused by deficient or insufficient endogenous GM-CSF examined the role of GM-CSF in mononuclear phagocyte disorders including autoimmune pulmonary alveolar proteinosis (aPAP), diverse infections (including COVID-19), wound healing, and anti-cancer immune checkpoint inhibitor therapy.

Results

We discuss emerging data for GM-CSF biology including the positive effects on mitochondrial function and cell metabolism, augmentation of phagocytosis and efferocytosis, and immune cell modulation. We further address how giving exogenous rhu GM-CSF may control or treat mononuclear phagocyte dysfunction disorders caused or exacerbated by GM-CSF deficiency or insufficiency. We discuss how rhu GM-CSF may augment the anti-cancer effects of immune checkpoint inhibitor immunotherapy as well as ameliorate immune-related adverse events.

Discussion

We identify research gaps, opportunities, and the concept that rhu GM-CSF, by supporting and restoring the metabolic capacity and function of mononuclear phagocytes, can have significant therapeutic effects. rhu GM-CSF (e.g., sargramostim) might ameliorate multiple diseases of GM-CSF deficiency or insufficiency and address a high unmet medical need.

COVID-19 in patients with pulmonary alveolar proteinosis: a European multicentre study

Adult PAP patients experience similar #COVID19 rates to the general population, and high rates of hospitalisation and deaths, underscoring their vulnerability and the need for measures to prevent infection. The impact of iGM-CSF must be considered. https://bit.ly/3M0wKnZ.

Assessment of Statin Treatment for Pulmonary Alveolar Proteinosis without Hypercholesterolemia: A 12-Month Prospective, Longitudinal, and Observational Study

Background

Pulmonary alveolar proteinosis (PAP) is a rare disorder which is characterized by the accumulation of excessive surfactant lipids and proteins in alveolar macrophages and alveoli. Oral statin therapy has been reported to be a novel therapy for PAP with hypercholesterolemia. We aimed to evaluate the safety and efficacy of oral statin therapy for PAP without hypercholesterolemia.

Methods

In a prospective real-world observational study, 47 PAP patients without hypercholesterolemia were screened. Oral statin was initiated as therapy for these PAP patients with 12 months of follow-up.

Results

Forty PAP patients completed the study. 26 (65%) of 40 PAP patients responded to statin therapy according to the study criteria. Partial pressure of arterial oxygen (PaO2) and percentage of diffusion capacity predicted (DLCO%) significantly increased while disease severity score (DSS) and radiographic abnormalities decreased after 12 months of statin therapy (all p < 0.05). The factors associated with response were higher levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody and baseline total cholesterol/high-density lipoprotein cholesterol (TC/HDL) (p = 0.015 and p = 0.035, respectively). The area under the receiver operating characteristic curve (AUROC) of dose of atorvastatin for predicting the response to statin therapy for PAP was 0.859 (95% CI: 0.738-0.979, p < 0.001). The cutoff dose of atorvastatin was 67.5 mg daily with their corresponding specificity (64.3%) and sensitivity (96.2%). No severe side effects were observed during the study.

Conclusions

In PAP patients without hypercholesterolemia, statin therapy resulted in improvements in arterial blood gas (ABG) measurement, pulmonary function, and radiographic assessment.

Interstitial lung diseases

Over 200 interstitial lung diseases, from ultra rare to relatively common, are recognised. Most interstitial lung diseases are characterised by inflammation or fibrosis within the interstitial space, the primary consequence of which is impaired gas exchange, resulting in breathlessness, diminished exercise tolerance, and decreased quality of life. Outcomes vary considerably for each of the different interstitial lung diseases. In some conditions, spontaneous reversibility or stabilisation can occur, but unfortunately in many people with interstitial lung disease, especially in those manifesting progressive pulmonary fibrosis, respiratory failure and death are a sad reality. Over the past 3 years, the field of interstitial lung disease has had important advances, with the approval of drugs to treat systemic sclerosis-associated interstitial lung disease, interstitial lung disease-associated pulmonary hypertension, and different forms of progressive pulmonary fibrosis. This Seminar provides an update on epidemiology, pathogenesis, presentation, diagnosis, disease course, and management of the interstitial lung diseases that are most frequently encountered in clinical practice. Furthermore, we describe how developments have led to a shift in the classification and treatment of interstitial lung diseases that exhibit progressive pulmonary fibrosis and summarise the latest practice-changing guidelines. We conclude with an outline of controversies, uncertainties, and future directions.

Progress in Respiratory Gene Therapy

The prospect of gene therapy for inherited and acquired respiratory disease has energized the research community since the 1980s, with cystic fibrosis, as a monogenic disorder, driving early efforts to develop effective strategies. The fact that there are still no approved gene therapy products for the lung, despite many early phase clinical trials, illustrates the scale of the challenge: In the 1990s, first-generation non-viral and viral vector systems demonstrated proof-of-concept but low efficacy. Since then, there has been steady progress toward improved vectors with the capacity to overcome at least some of the formidable barriers presented by the lung. In addition, the inclusion of features such as codon optimization and promoters providing long-term expression have improved the expression characteristics of therapeutic transgenes. Early approaches were based on gene addition, where a new DNA copy of a gene is introduced to complement a genetic mutation: however, the advent of RNA-based products that can directly express a therapeutic protein or manipulate gene expression, together with the expanding range of tools for gene editing, has stimulated the development of alternative approaches. This review discusses the range of vector systems being evaluated for lung delivery; the variety of cargoes they deliver, including DNA, antisense oligonucleotides, messenger RNA (mRNA), small interfering RNA (siRNA), and peptide nucleic acids; and exemplifies progress in selected respiratory disease indications.

Evaluating how clear the questions being investigated in randomised trials are: systematic review of estimands

OBJECTIVES

To evaluate how often the precise research question being addressed about an intervention (the estimand) is stated or can be determined from reported methods, and to identify what types of questions are being investigated in phase 2-4 randomised trials.

DESIGN

Systematic review of the clarity of research questions being investigated in randomised trials in 2020 in six leading general medical journals.

DATA SOURCE

PubMed search in February 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Phase 2-4 randomised trials, with no restrictions on medical conditions or interventions. Cluster randomised, crossover, non-inferiority, and equivalence trials were excluded.

MAIN OUTCOME MEASURES

Number of trials that stated the precise primary question being addressed about an intervention (ie, the primary estimand), or for which the primary estimand could be determined unambiguously from the reported methods using statistical knowledge. Strategies used to handle post-randomisation events that affect the interpretation or existence of patient outcomes, such as intervention discontinuations or uses of additional drug treatments (known as intercurrent events), and the corresponding types of questions being investigated.

RESULTS

255 eligible randomised trials were identified. No trials clearly stated all the attributes of the estimand. In 117 (46%) of 255 trials, the primary estimand could be determined from the reported methods. Intercurrent events were reported in 242 (95%) of 255 trials; but the handling of these could only be determined in 125 (49%) of 255 trials. Most trials that provided this information considered the occurrence of intercurrent events as irrelevant in the calculation of the treatment effect and assessed the effect of the intervention regardless (96/125, 77%)-that is, they used a treatment policy strategy. Four (4%) of 99 trials with treatment non-adherence owing to adverse events estimated the treatment effect in a hypothetical setting (ie, the effect as if participants continued treatment despite adverse events), and 19 (79%) of 24 trials where some patients died estimated the treatment effect in a hypothetical setting (ie, the effect as if participants did not die).

CONCLUSIONS

The precise research question being investigated in most trials is unclear, mainly because of a lack of clarity on the approach to handling intercurrent events. Clear reporting of estimands is necessary in trial reports so that all stakeholders, including clinicians, patients and policy makers, can make fully informed decisions about medical interventions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021238053.

Correction of a chronic pulmonary disease through lentiviral vector-mediated protein expression

We developed a novel lentiviral vector, pseudotyped with the F and HN proteins from Sendai virus (rSIV.F/HN), that produces long-lasting, high-efficiency transduction of the respiratory epithelium. Here we addressed whether this platform technology can secrete sufficient levels of a therapeutic protein into the lungs to ameliorate a fatal pulmonary disease as an example of its translational capability. Pulmonary alveolar proteinosis (PAP) results from alveolar granulocyte-macrophage colony-stimulating factor (GM-CSF) insufficiency, resulting in abnormal surfactant homeostasis and consequent ventilatory problems. Lungs of GM-CSF knockout mice were transduced with a single dose of rSIV.F/HN-expressing murine GM-CSF (mGM-CSF; 1e5-92e7 transduction units [TU]/mouse); mGM-CSF expression was dose related and persisted for at least 11 months. PAP disease biomarkers were rapidly and persistently corrected, but we noted a narrow toxicity/efficacy window. rSIV.F/HN may be a useful platform technology to deliver therapeutic proteins for lung diseases requiring long-lasting and stable expression of secreted proteins.

Autoimmune Pulmonary Alveolar Proteinosis

Autoimmune pulmonary alveolar proteinosis (PAP) is a rare disease characterized by myeloid cell dysfunction, abnormal pulmonary surfactant accumulation, and innate immune deficiency. It has a prevalence of 7-10 per million; occurs in individuals of all races, geographic regions, sex, and socioeconomic status; and accounts for 90% of all patients with PAP syndrome. The most common presentation is dyspnea of insidious onset with or without cough, production of scant white and frothy sputum, and diffuse radiographic infiltrates in a previously healthy adult, but it can also occur in children as young as 3 years. Digital clubbing, fever, and hemoptysis are not typical, and the latter two indicate that intercurrent infection may be present. Low prevalence and nonspecific clinical, radiological, and laboratory findings commonly lead to misdiagnosis as pneumonia and substantially delay an accurate diagnosis. The clinical course, although variable, usually includes progressive hypoxemic respiratory insufficiency and, in some patients, secondary infections, pulmonary fibrosis, respiratory failure, and death. Two decades of research have raised autoimmune PAP from obscurity to a paradigm of molecular pathogenesis-based diagnostic and therapeutic development. Pathogenesis is driven by GM-CSF (granulocyte/macrophage colony-stimulating factor) autoantibodies, which are present at high concentrations in blood and tissues and form the basis of an accurate, commercially available diagnostic blood test with sensitivity and specificity of 100%. Although whole-lung lavage remains the first-line therapy, inhaled GM-CSF is a promising pharmacotherapeutic approach demonstrated in well-controlled trials to be safe, well tolerated, and efficacious. Research has established GM-CSF as a pulmonary regulatory molecule critical to surfactant homeostasis, alveolar stability, lung function, and host defense.

Opportunistic Infection Associated with Elevated GM-CSF Autoantibodies: A Case Series and Review of the Literature

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is known to play a key role in enhancing multiple immune functions that affect response to infectious pathogens including antigen presentation, complement- and antibody-mediated phagocytosis, microbicidal activity, and neutrophil chemotaxis. Reduced GM-CSF activity and immune response provides a mechanism for increased infection risk associated with autoimmune pulmonary alveolar proteinosis (aPAP) and other disorders involving the presence of GM-CSF autoantibodies. We present a case series of five patients with persistent or unusual pulmonary and central nervous system opportunistic infections (Cryptococcus gattii, Flavobacterium, Nocardia) and elevated GM-CSF autoantibody levels, as well as 27 cases identified on systematic review of the literature.

The pre-induction temperature affects recombinant HuGM-CSF aggregation in thermoinducible Escherichia coli

The overproduction of recombinant proteins in Escherichia coli leads to insoluble aggregates of proteins called inclusion bodies (IBs). IBs are considered dynamic entities that harbor high percentages of the recombinant protein, which can be found in different conformational states. The production conditions influence the properties of IBs and recombinant protein recovery and solubilization. The E. coli growth in thermoinduced systems is generally carried out at 30 °C and then recombinant protein production at 42 °C. Since the heat shock response in E. coli is triggered above 34 °C, the synthesis of heat shock proteins can modify the yields of the recombinant protein and the structural quality of IBs. The objective of this work was to evaluate the effect of different pre-induction temperatures (30 and 34 °C) on the growth of E. coli W3110 producing the human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF) and on the IBs structure in a λpL/pR-cI857 thermoinducible system. The recombinant E. coli cultures growing at 34 °C showed a ~ 69% increase in the specific growth rate compared to cultures grown at 30 °C. The amount of rHuGM-CSF in IBs was significantly higher in cultures grown at 34 °C. Main folding chaperones (DnaK and GroEL) were associated with IBs and their co-chaperones (DnaJ and GroES) with the soluble protein fraction. Finally, IBs from cultures that grew at 34 °C had a lower content of amyloid-like structure and were more sensitive to proteolytic degradation than IBs obtained from cultures at 30 °C. Our study presents evidence that increasing the pre-induction temperature in a thermoinduced system allows obtaining higher recombinant protein and reducing amyloid contents of the IBs. KEY POINTS: • Pre-induction temperature determines inclusion bodies architecture • In pre-induction (above 34 °C), the heat shock response increases recombinant protein production • Inclusion bodies at higher pre-induction temperature show a lower amyloid content.

Rituximab rescue therapy for autoimmune pulmonary alveolar proteinosis

Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare lung disease characterised by abnormal alveolar surfactant accumulation due to macrophage dysfunction. Whole lung lavage (WLL) is the cornerstone of first-line aPAP therapy, but effective rescue treatments have not yet been well established. We report a case of a 41-year-old man with aPAP in whom further WLL is contraindicated. His diagnosis was established using a combination of classical radiological findings, positive serum GM-CSF IgG antibodies and bronchoalveolar lavage (BAL) findings. Following a literature review of emerging therapies, a decision was made to treat with a course of rituximab to suppress GM-CSF autoantibody production and restore alveolar surfactant-macrophage homeostasis. A significant clinical response was demonstrated within 6 months with improvements in arterial oxygenation, respiratory membrane gas diffusion, six-minute walk test and radiological findings.

A Bibliometric Analysis of Pulmonary Alveolar Proteinosis From 2001 to 2021

Background

Pulmonary alveolar proteinosis (PAP) is a rare syndrome first described by Rosen et al. in 1958. Despite our considerably evolved understanding of PAP over the past decades, no bibliometric studies have been reported on this field. We aimed to analyze and visualize the research hotspots and current trends of the PAP research field using a bibliometric analysis to help understand the future development of basic and clinical research.

Methods

The literature regarding PAP was culled from the Web of Science Core Collection (WoSCC) database. Data were extracted from the relevant articles and visually analyzed using CiteSpace and VOSviewer software.

Results

Nine hundred and nine qualifying articles were included in the analysis. Publications regarding PAP increased over time. These articles mainly come from 407 institutions of 57 countries. The leading countries were the USA and Japan. University of Cincinnati (USA) and Niigata University (Japan) featured the highest number of publications among all institutions. Bruce C Trapnell exerts a significant publication impact and has made the most outstanding contributions in the field of PAP. American Journal of Physiology-Lung Cellular and Molecular Physiology was the journal with the most publications, and American Journal of Respiratory and Critical Care Medicine was the most commonly cited journal. All the top 5 co-cited journals belong to Q1. Keyword citation bursts revealed that inflammation, deficiency, tissue resident macrophage, classification, autoimmune pulmonary alveolar proteinosis, sarcoidosis, gm csf, high resolution ct, and fetal monocyte were the emerging research hotspots.

Conclusion

Research on PAP is prosperous. International cooperation is also expected to deepen and strengthen in the future. Our results indicated that the etiology and pathogenesis of PAP, current and emerging therapies, especially the novel pathogenesis-based options will remain research hotspots in the future.

Sputum from patients with primary ciliary dyskinesia contains high numbers of dysfunctional neutrophils and inhibits efferocytosis

BACKGROUND

Primary ciliary dyskinesia (PCD) is a genetic disorder characterized by recurrent airway infection and inflammation. There is no cure for PCD and to date there are no specific treatments available. Neutrophils are a crucial part of the immune system and are known to be dysfunctional in many inflammatory diseases. So far, the role of the neutrophils in PCD airways is largely unknown. The purpose of this study was to investigate the phenotype and function of airway neutrophils in PCD, and compare them to blood neutrophils.

METHODS

Paired peripheral blood and spontaneously expectorated sputum samples from patients with PCD (n = 32) and a control group of patients with non-PCD, non-cystic fibrosis bronchiectasis (n = 5) were collected. The expression of neutrophil-specific surface receptors was determined by flow cytometry. Neutrophil function was assessed by measuring the extent of actin polymerization, production of reactive oxygen species (ROS) and release of neutrophil extracellular traps (NETs) in response to activating stimuli.

RESULTS

Sputum neutrophils displayed a highly activated phenotype and were unresponsive to stimuli that would normally induce ROS production, actin polymerization and the expulsion of NETs. In addition, PCD sputum displayed high activity of neutrophil elastase, and impaired the efferocytosis by healthy donor macrophages.

CONCLUSIONS

Sputum neutrophils in PCD are dysfunctional and likely contribute to ongoing inflammation in PCD airways. Further research should focus on anti-inflammatory therapies and stimulation of efferocytosis as a strategy to treat PCD.

Anticytokine autoantibodies: Autoimmunity trespassing on antimicrobial immunity

Anticytokine autoantibodies can cause immunodeficiency or dysregulate immune responses. They may phenocopy genetically defined primary immunodeficiencies. We review current anti-type 1 and anti-type 2 interferon; anti-IL-12/23, anti-IL-17, and anti-GM-CSF autoantibodies; HLA associations; disease associations; and mechanistically based treatment options. Suspecting the presence of these autoantibodies in patients and identifying them at the onset of symptoms should ameliorate disease and improve outcomes.

Pathogenesis and Treatment of Refractory Disease Courses in Systemic Juvenile Idiopathic Arthritis: Refractory Arthritis, Recurrent Macrophage Activation Syndrome and Chronic Lung Disease

Systemic juvenile idiopathic arthritis is a distinct and heterogeneous disease presently classified under the umbrella of juvenile idiopathic arthritis, with some patients following a monophasic remitting course, whereas others have persistent disease with chronic organ- and life-threatening complications. Although biologic therapies have revolutionized treatment, recent follow-up studies report significant numbers of children with persistently active disease on long term follow-up. This review focuses on refractory disease courses, specifically refractory arthritis, systemic juvenile idiopathic arthritis with recurrent, or longstanding signs of macrophage activation syndrome, and systemic juvenile idiopathic arthritis associated with suspected, probable, or definite lung disease.

Update on Diagnosis and Treatment of Adult Pulmonary Alveolar Proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary surfactant homeostasis disorder resulting in buildup of lipo-proteinaceous material within the alveoli. PAP is classified as primary (autoimmune and hereditary), secondary, congenital and unclassifiable type based on the underlying pathogenesis. PAP has an insidious onset and can, in some cases, progress to severe respiratory failure. Diagnosis is often secured with bronchoalveolar lavage in the setting of classic imaging findings. Recent insights into genetic alterations and autoimmune mechanisms have provided newer diagnostics and treatment options. In this review, we discuss the etiopathogenesis, diagnosis and treatment options available and emerging for PAP.

Autoimmune pulmonary alveolar proteinosis successfully treated with lung lavage in an adolescent patient: a case report

Background

Pulmonary alveolar proteinosis is a rare interstitial lung disease characterized by accumulating surfactant materials in the alveoli. The autoimmune form is by far the most common in adults, while in the pediatric age group, the vast majority of cases are congenital. We report a case of an adolescent patient diagnosed with autoimmune pulmonary alveolar proteinosis, which is unusual in this age group.

Case presentation

A-15 year-old Saudi male presented to the emergency department with a history of shortness of breath and low oxygen saturation. High-resolution computed tomography of his chest showed a global crazy-paving pattern. Autoantibodies against granulocyte-macrophage colony-stimulating factor were detected in his serum. A diagnosis of the autoimmune form of pulmonary alveolar proteinosis was confirmed after excluding other possible causes. The patient improved after he underwent whole lung lavage under general anesthesia, and he was independent of oxygen therapy after 6 months of follow-up.

Conclusion

The autoimmune form of pulmonary alveolar proteinosis is rare in the pediatric age group and should be considered when no apparent cause of this disease was found. Whole lung lavage should be the first treatment modality offered in this setting with close follow-up and monitoring.

Long-term follow-up and successful treatment of pulmonary alveolar proteinosis without hypercholesterolemia with statin therapy: a case report

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by the accumulation of excessive surfactant lipids and proteins in alveolar macrophages and alveoli. Oral statin therapy is a novel treatment for PAP with hypercholesterolemia. However, this treatment has never been described in a patient without hypercholesterolemia. Here, we present a case of successful treatment with atorvastatin for a patient with possibly unclassified PAP without hypercholesterolemia who responded poorly to whole lung lavage therapy and inhaled granulocyte-macrophage colony-stimulating factor. After 18 months of atorvastatin treatment, the patient experienced improvements in dyspnea, radiographic abnormalities and pulmonary function. The present case study supports the feasibility of statin therapy for PAP regardless of the level of cholesterol.

Autoimmune pulmonary alveolar proteinosis and idiopathic pulmonary haemosiderosis: a dual pathology

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary condition which leads to excessive accumulation of proteinaceous material within the alveoli. Idiopathic pulmonary haemosiderosis (IPH) is another orphan lung disease and results in recurrent alveolar haemorrhage. This case study describes a case of these two rare pathologies occurring together. A man in his 50s presented with a 6-week history of haemoptysis and worsening dyspnoea. A CT scan of the thorax showed multifocal, bilateral ground glass opacification with a wide differential diagnosis. Full autoantibody screen including myositis panel and coeliac screen were negative. Bronchoscopy with bronchoalveolar lavage and tissue from a transbronchial lung cryobiopsy were non-diagnostic. Tissue from a video-assisted thoracoscopic surgery biopsy confirmed a diagnosis of PAP with IPH as a second separate pathology. The association of IPH and PAP has not previously been described. We discuss these conditions and postulate how and if they may be related.

B cell-activating factors in autoimmune pulmonary alveolar proteinosis

Background

Autoimmune pulmonary alveolar proteinosis (APAP) results from the suppression of granulocyte-macrophage colony-stimulating factor (GM-CSF) signaling by a neutralizing autoantibody against GM-CSF. B cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are involved in immunoglobulin G production and are overproduced in various autoimmune disorders. We hypothesized that BAFF and/or APRIL levels would be elevated in serum and bronchoalveolar lavage fluid (BALF) and serum and BALF levels of BAFF and APRIL respond to the treatments (whole lung lavage (WLL) or inhalation of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF)) in patients with APAP.

Subjects and methods

BAFF and APRIL levels in serum and BALF from 110 patients with APAP were measured at baseline and during and after treatment, using an enzyme-linked immunosorbent assay kit. We enrolled 34 healthy volunteers as serum cytokine controls, and 13 disease controls for BALF. Associations of BAFF and APRIL levels with clinical measures were assessed to clarify their clinical roles.

Results

In patients with APAP, serum BAFF and APRIL levels were significantly increased relative to healthy volunteers (p < 0.0001 and p < 0.05, respectively), and BALF BAFF and APRIL levels were significantly increased versus disease controls (p < 0.0001 and p < 0.01, respectively). Serum BAFF levels (but not APRIL levels) were significantly correlated with Krebs von den Lungen-6 (KL-6), surfactant protein (SP)-D, SP-A, and lactate dehydrogenase (p < 0.0001). There was no significant correlation between serum BAFF or APRIL levels and anti-GM-CSF autoantibody. BAFF and APRIL were negatively correlated with single-breath diffusion capacity for carbon monoxide (DLco) (p = 0.004) and forced vital capacity (p = 0.04), respectively. BAFF (but not APRIL) in BALF was negatively correlated with vital capacity (p = 0.04) and DLco (p = 0.006). There were significant correlations between disease severity and BAFF levels in serum (p = 0.04) and BALF (p = 0.007). Serum levels of anti-GM-CSF autoantibody, BAFF, and APRIL were not significantly affected by WLL or inhalation of recombinant human GM-CSF.

Conclusions

BAFF and APRIL levels of sera and BALF in APAP were significantly increased compared with healthy volunteer and disease control, and the BAFF and APRIL pathway might have important specific roles in pathogenesis of APAP. Our data suggest a new perspective of future treatment for APAP.

Challenges and opportunities for antiviral monoclonal antibodies as COVID-19 therapy

To address the COVID-19 pandemic, there has been an unprecedented global effort to advance potent neutralizing mAbs against SARS-CoV-2 as therapeutics. However, historical efforts to advance antiviral monoclonal antibodies (mAbs) for the treatment of other respiratory infections have been met with categorical failures in the clinic. By investigating the mechanism by which SARS-CoV-2 and similar viruses spread within the lung, along with available biodistribution data for systemically injected mAb, we highlight the challenges faced by current antiviral mAbs for COVID-19. We summarize some of the leading mAbs currently in development, and present the evidence supporting inhaled delivery of antiviral mAb as an early intervention against COVID-19 that could prevent important pulmonary morbidities associated with the infection.