Pulmonary alveolar proteinosis

X-linked hyper-IgM syndrome associated with pulmonary manifestations: A very rare case of functional mutation in CD40L gene in Iran

Hyper IgM (HIGM) syndromes are a complex of primary immunodeficiency disorders. A 4-years-old boy with recurrent fever and chills, dyspnea, sort throat for a month was admitted to emergency department. In the current case, whole exome sequencing followed by Sanger sequencing were employed in order to screen probable functional mutations. Molecular analysis revealed a functional mutation across the CD40L gene (NM_000074: exon5: c.T464C) resulted in amino acid change p.L155P attributed to X-linked hyper IgM syndrome. The findings of the current study signify the critical role of microbial infection as well as XHIGM screening, particularly in those children cases with respiratory symptoms.

Heterozygous Mutations in OAS1 Cause Infantile-Onset Pulmonary Alveolar Proteinosis with Hypogammaglobulinemia

Pulmonary alveolar proteinosis (PAP) is characterized by accumulation of a surfactant-like substance in alveolar spaces and hypoxemic respiratory failure. Genetic PAP (GPAP) is caused by mutations in genes encoding surfactant proteins or genes encoding a surfactant phospholipid transporter in alveolar type II epithelial cells. GPAP is also caused by mutations in genes whose products are implicated in surfactant catabolism in alveolar macrophages (AMs). We performed whole-exome sequence analysis in a family affected by infantile-onset PAP with hypogammaglobulinemia without causative mutations in genes associated with PAP: SFTPB, SFTPC, ABCA3, CSF2RA, CSF2RB, and GATA2. We identified a heterozygous missense variation in OAS1, encoding 2,′5′-oligoadenylate synthetase 1 (OAS1) in three affected siblings, but not in unaffected family members. Deep sequence analysis with next-generation sequencing indicated 3.81% mosaicism of this variant in DNA from their mother’s peripheral blood leukocytes, suggesting that PAP observed in this family could be inherited as an autosomal-dominant trait from the mother. We identified two additional de novo heterozygous missense variations of OAS1 in two unrelated simplex individuals also manifesting infantile-onset PAP with hypogammaglobulinemia. PAP in the two simplex individuals resolved after hematopoietic stem cell transplantation, indicating that OAS1 dysfunction is associated with impaired surfactant catabolism due to the defects in AMs.

Innate Immunity of the Lung: From Basic Mechanisms to Translational Medicine

The respiratory tract is faced daily with 10,000 L of inhaled air. While the majority of air contains harmless environmental components, the pulmonary immune system also has to cope with harmful microbial or sterile threats and react rapidly to protect the host at this intimate barrier zone. The airways are endowed with a broad armamentarium of cellular and humoral host defense mechanisms, most of which belong to the innate arm of the immune system. The complex interplay between resident and infiltrating immune cells and secreted innate immune proteins shapes the outcome of host-pathogen, host-allergen, and host-particle interactions within the mucosal airway compartment. Here, we summarize and discuss recent findings on pulmonary innate immunity and highlight key pathways relevant for biomarker and therapeutic targeting strategies for acute and chronic diseases of the respiratory tract.

Cytopathological examination of bronchoalveolar lavage fluid in diagnosis of pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by the deposition of extracellular lipoproteinaceous material within the air spaces. Although the diagnosis is mainly based on histopathological findings, sometimes, the diagnostic yield of transbronchial and even open lung biopsy can be unsatisfactory. The advantage with bronchoalveolar lavage (BAL) cytology is that apart from being safer for the patient, it can sample a much wider area and help in giving an early diagnosis and treatment to the patient. Herein, we present a case of PAP diagnosed on BAL fluid cytology in an elderly female.

Macrophages and lipid metabolism

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The transcriptional signature of Kupffer cells & Alveolar macrophages are enriched for lipid metabolism genes.

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Lipid metabolism may control macrophage phenotype.

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Dysregulated lipid metabolism in macrophages contributes to disease pathology.

Distinct macrophage populations throughout the body display highly heterogeneous transcriptional and epigenetic programs. Recent research has highlighted that these profiles enable the different macrophage populations to perform distinct functions as required in their tissue of residence, in addition to the prototypical macrophage functions such as in innate immunity. These ‘extra’ tissue-specific functions have been termed accessory functions. One such putative accessory function is lipid metabolism, with macrophages in the lung and liver in particular being associated with this function. As it is now appreciated that cell metabolism not only provides energy but also greatly influences the phenotype and function of the cell, here we review how lipid metabolism affects macrophage phenotype and function and the specific roles played by macrophages in the pathogenesis of lipid-related diseases. In addition, we highlight the current questions limiting our understanding of the role of macrophages in lipid metabolism.

Secondary pulmonary alveolar proteinosis: a single-center retrospective study (a case series and literature review)

Background

Secondary pulmonary alveolar proteinosis (sPAP) is an extremely rare disease. The clinical features of sPAP patients remain to be summarizeds.

Methods

Patients pathologically diagnosed with PAP and with negative results for anti-granulocyte macrophage colony stimulating factor (GM-CSF) autoantibodies from Peking Union Medical College Hospital between January 2000 and July 2016 were retrospectively studied. The PubMed database was also searched for literature to collect published cases.

Results

In our center, nine patients were diagnosed as sPAP with a median age of 37 years. Hematological disorders, including myelodysplastic syndrome (MDS), chronic myelogenous leukemia (CML), and pulmonary tuberculosis (TB) infection were the underlying diseases. Cases secondary to MDS had very poor prognosis as all of them survived less than 2 years after their diagnosis, while those secondary to TB had favorable prognosis. Only 33.3% of cases showed interlobular septal thickening in our sPAP group. Through literature review, 164 sPAP cases were collected. The age at diagnosis was 45.0 ± 14.8 years old and the gender radio was 1.20:1 (M:F). 61.9% of cases were diagnosed by bronchoscopy. MDS and CML were common underlying diseases in 34.1% and 15.2% of patients, respectively. Patients with sPAP secondary to hematological diseases had a short survival time and half of them died within 14.95 months after diagnosis.

Conclusions

MDS and TB infection were the most frequent underlying causes of sPAP in this single-center research in China, with cases secondary to MDS having a poor survival rate. sPAP was more likely to be secondary to hematological disorders, especially MDS and CML and had a fairly poor prognosis in published cases. sPAP should be suspected in PAP patients whose CT scan presents only ground-glass opacities without interlobular septal thickening.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0590-z) contains supplementary material, which is available to authorized users.

Accelerating Scientific Advancement for Pediatric Rare Lung Disease Research. Report from a National Institutes of Health-NHLBI Workshop, September 3 and 4, 2015

Pediatric rare lung disease (PRLD) is a term that refers to a heterogeneous group of rare disorders in children. In recent years, this field has experienced significant progress marked by scientific discoveries, multicenter and interdisciplinary collaborations, and efforts of patient advocates. Although genetic mechanisms underlie many PRLDs, pathogenesis remains uncertain for many of these disorders. Furthermore, epidemiology and natural history are insufficiently defined, and therapies are limited. To develop strategies to accelerate scientific advancement for PRLD research, the NHLBI of the National Institutes of Health convened a strategic planning workshop on September 3 and 4, 2015. The workshop brought together a group of scientific experts, intramural and extramural investigators, and advocacy groups with the following objectives: (1) to discuss the current state of PRLD research; (2) to identify scientific gaps and barriers to increasing research and improving outcomes for PRLDs; (3) to identify technologies, tools, and reagents that could be leveraged to accelerate advancement of research in this field; and (4) to develop priorities for research aimed at improving patient outcomes and quality of life. This report summarizes the workshop discussion and provides specific recommendations to guide future research in PRLD.

Monogenic diseases in respiratory medicine: Clinical perspectives

With the increasing awareness of genetics in respiratory medicine and improvements in molecular diagnostic techniques, many complicated and rare diseases in respiratory medicine can be diagnosed. Most respiratory diseases have no specific phenotype. However, the clinical spectrum of monogenic diseases in respiratory medicine varies, from pulmonary disease to other inherited disorders that involve the lung. The genes that mediate some of these diseases have been identified. Certain monogenic diseases remain poorly characterized clinically. Because of the specificity of the phenotype of respiratory disease, a future challenge will be to correlate the phenotype and genotype and understand its phenotypic variability. With the development of precision medicine, research on monogenic disorders has been intensive and vigorous. In this article, we provide a brief clinical introduction to monogenic diseases in pediatrics.

Hematopoietic stem cell transplantation for pulmonary alveolar proteinosis associated with primary immunodeficiency disease

Pulmonary alveolar proteinosis (PAP) is a rare disorder that is characterized by the excessive accumulation of surfactant-like materials in the alveoli, leading to hypoxemic respiratory failure. We describe two Japanese infants with PAP associated with hypogammaglobulinemia and monocytopenia. These patients may have underlying primary immunodeficiency (PID) and were successfully treated with allogeneic hematopoietic stem cell transplantation (HSCT). This report indicates that allogeneic HSCT may provide a curative treatment for PAP associated with PID.

Clinical significance of cigarette smoking and dust exposure in pulmonary alveolar proteinosis: a Korean national survey

BACKGROUND

This study aimed to investigate clinical characteristics of Korean PAP patients and to examine the potential risk factors of PAP.

METHODS

We retrospectively reviewed medical records of 78 Korean PAP patients diagnosed between 1993 and 2014. Patients were classified into two groups according to the presence/absence of treatment (lavage). Clinical and laboratory features were compared between the two groups.

RESULTS

Of the total 78 PAP patients, 60% were male and median age at diagnosis was 47.5 years. Fifty three percent were ever smokers (median 22 pack-years) and 48% had a history of dust exposure (metal 26.5%, stone or sand 20.6%, chemical or paint 17.7%, farming dust 14.7%, diesel 14.7%, textile 2.9%, and wood 2.9%). A history of cigarette smoking or dust exposure was present in 70.5% of the total PAP patients, with 23% having both of them. Patients who underwent lavage (n = 38) presented symptoms more frequently (38/38 [100%] vs. 24/40 [60%], P < 0.001) and had significantly lower PaO₂ and DL_CO with higher D(A-a)O₂ at the onset of disease than those without lavage (n = 40) (P = 0.006, P < 0.001, and P = 0.036, respectively). Correspondingly, the distribution of disease severity score (DSS) differed significantly between the two groups (P = 0.001). Based on these, when the total patients were categorized according to DSS (low DSS [DSS 1-2] vs. high DSS [DSS 3-5]), smoking status differed significantly between the two groups with the proportion of current smokers significantly higher in the high DSS group (11/22 [50%] vs. 7/39 [17.9%], P = 0.008). Furthermore, current smokers had meaningfully higher DSS and serum CEA levels than non-current smokers (P = 0.011 and P = 0.031), whereas no difference was found between smokers and non-smokers. Regarding type of exposed dust, farming dust was significantly associated with more severe form of PAP (P = 0.004).

CONCLUSION

A considerable proportion of PAP patients had a history of cigarette smoking and/or dust exposure, suggestive of their possible roles in the development of PAP. Active cigarette smoking at the onset of PAP is associated with the severity of PAP.

Clinical features of secondary pulmonary alveolar proteinosis associated with myelodysplastic syndrome: Two case reports

RATIONALE

Pulmonary alveolar proteinosis (PAP) is a rare lung disorder characterized by the abnormal accumulation of alveolar surfactant protein in alveolar spaces. Secondary PAP can result from myelodysplastic syndrome (MDS).

PATIENT CONCERNS

But most reports described a single case; here we reported 2 cases of PAP secondary to MDS. One case developed secondary PAP at the same time as MDS, and the other developed during the course of MDS.

DIAGNOSES

The diagnosis of PAP was made by bronchoalveolar lavage and based on the identification of periodic acid-Schiff-positive proteinaceous material. Chest high resolution CT (HRCT) scans showed variable distribution of ground glass opacities, but crazy-paving appearance was not seen in our 2 cases.

INTERVENTIONS

Because the patients' general conditions were poor, whole lung lavage was not used in the 2 cases.

OUTCOMES

And the 2 cases' prognoses were poor.

LESSONS

In conclusion, pulmonary physicians should suspect the possibility of secondary PAP when they encounter unexplained pulmonary infiltrates with some hematologic or infectious disease that shows diffuse bilateral GGO on an HRCT scan.

Bilateral lung disease, extensive and diffuse. Diagnosis of pulmonary alveolar proteinosis by bronchoscopic cryobiopsy

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by the intra-alveolar accumulation of a proteinaceous phospholipid-laden material called surfactant. Clinically, this disease should be suspected with respiratory failure in association with a crazy paving pattern on high-resolution chest computed tomography. We report a 24-year-old gentleman who was referred to us for a history of respiratory failure, treatment with invasive ventilation and tracheostomy. His blood exams and biochemistry were normal. His infectious and rheumatological panel was negative for a secondary disease. A flexible bronchoscopy with a transbronchial biopsy through a CryoProbe was performed. An anatomopathological analysis was periodic acid-Schiff positive for PAP. A CryoProbe is a recently developed diagnostic tool that improves the diagnostic yield in diffuse lung diseases compared to bronchoscopy with transbronchial biopsy. This method should be considered for patients with diffuse lung disease and PAP.

Inflammatory responses induce an identity crisis of alveolar macrophages, leading to pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a severe respiratory disease characterized by dyspnea caused by accumulation of surfactant protein. Dysfunction of alveolar macrophages (AMs), which regulate the homeostasis of surfactant protein, leads to the development of PAP; for example, in mice lacking BTB and CNC homology 2 (Bach2). However, how Bach2 helps prevent PAP is unknown, and the cell-specific effects of Bach2 are undefined. Using mice lacking Bach2 in specific cell types, we found that the PAP phenotype of Bach2-deficient mice is due to Bach2 deficiency in more than two types of immune cells. Depletion of hyperactivated T cells in Bach2-deficient mice restored normal function of AMs and ameliorated PAP. We also found that, in Bach2-deficient mice, hyperactivated T cells induced gene expression patterns that are specific to other tissue-resident macrophages and dendritic cells. Moreover, Bach2-deficient AMs exhibited a reduction in cell cycle progression. IFN-γ released from T cells induced Bach2 expression in AMs, in which Bach2 then bound to regulatory regions of inflammation-associated genes in myeloid cells. Of note, in AMs, Bach2 restricted aberrant responses to excessive T cell-induced inflammation, whereas, in T cells, Bach2 puts a brake on T cell activation. Moreover, Bach2 stimulated the expression of multiple histone genes in AMs, suggesting a role of Bach2 in proper histone expression. We conclude that Bach2 is critical for the maintenance of AM identity and self-renewal in inflammatory environments. Treatments targeting T cells may offer new therapeutic strategies for managing secondary PAP.

Targeting cholesterol homeostasis in lung diseases

Macrophages are critical to organ structure and function in health and disease. To determine mechanisms by which granulocyte/macrophage-colony stimulating factor (GM-CSF) signaling normally maintains surfactant homeostasis and how its disruption causes pulmonary alveolar proteinosis (PAP), we evaluated lipid composition in alveolar macrophages and lung surfactant, macrophage-mediated surfactant clearance kinetics/dynamics, and cholesterol-targeted pharmacotherapy of PAP in vitro and in vivo. Without GM-CSF signaling, surfactant-exposed macrophages massively accumulated cholesterol ester-rich lipid-droplets and surfactant had an increased proportion of cholesterol. GM-CSF regulated cholesterol clearance in macrophages in constitutive, dose-dependent, and reversible fashion but did not affect phospholipid clearance. PPARγ-agonist therapy increased cholesterol clearance in macrophages and reduced disease severity in PAP mice. Results demonstrate that GM-CSF is required for cholesterol clearance in macrophages, identify reduced cholesterol clearance as the primary macrophage defect driving PAP pathogenesis, and support the feasibility of translating pioglitazone as a novel pharmacotherapy of PAP.

An Official American Thoracic Society Workshop Report: Translational Research in Rare Respiratory Diseases

Rare respiratory diseases (RRDs) are a heterogeneous group of disorders that collectively represent a significant health care burden. In recent years, strong advocacy and policy initiatives have led to advances in the implementation of research and clinical care for rare diseases. The development of specialized centers and research networks has facilitated support for affected individuals as well as emerging programs in basic, translational, and clinical research. In selected RRDs, subsequent gains in knowledge have informed the development of targeted therapies and effective diagnostic tests, but many gaps persist. There was therefore a desire to identify the elements contributing to an effective translational research program in RRDs. To this end, a workshop was convened in October 2015 with a focus on the implementation of effective transnational research networks and collaborations aimed at developing novel diagnostic and therapeutic tools. Key elements included an emphasis on molecular pathogenesis, the continuing engagement of patient advocacy groups and policy makers, the effective use of preclinical models in the translational research pipeline, and the detailed phenotyping of patient cohorts. During the course of the workshop, current logistical and knowledge gaps were identified, and new solutions or opportunities were highlighted.

Twenty-Eight-Day Repeated Inhalation Toxicity Study of Nano-Sized Neodymium Oxide in Male Sprague-Dawley Rats

Neodymium is a future-oriented material due to its unique properties, and its use is increasing in various industrial fields worldwide. However, the toxicity caused by repeated exposure to this metal has not been studied in detail thus far. The present study was carried out to investigate the potential inhalation toxicity of nano-sized neodymium oxide (Nd₂O₃) following a 28-day repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed to nano-sized Nd₂O₃-containing aerosols via a nose-only inhalation system at doses of 0 mg/m³, 0.5 mg/m³, 2.5 mg/m³, and 10 mg/m³ for 6 hr/day, 5 days/week over a 28-day period, followed by a 28-day recovery period. During the experimental period, clinical signs, body weight, hematologic parameters, serum biochemical parameters, necropsy findings, organ weight, and histopathological findings were examined; neodymium distribution in the major organs and blood, bronchoalveolar lavage fluid (BALF), and oxidative stress in lung tissues were analyzed. Most of the neodymium was found to be deposited in lung tissues, showing a dose-dependent relationship. Infiltration of inflammatory cells and pulmonary alveolar proteinosis (PAP) were the main observations of lung histopathology. Infiltration of inflammatory cells was observed in the 2.5 mg/m³ and higher dose treatment groups. PAP was observed in all treatment groups accompanied by an increase in lung weight, but was observed to a lesser extent in the 0.5 mg/m³ treatment group. In BALF analysis, total cell counts, including macrophages and neutrophils, lactate dehydrogenase, albumin, interleukin-6, and tumor necrosis factor-alpha, increased significantly in all treatment groups. After a 4-week recovery period, these changes were generally reversed in the 0.5 mg/m³ group, but were exacerbated in the 10 mg/m³ group. The lowest-observed-adverse-effect concentration of nano-sized Nd₂O₃ was determined to be 0.5 mg/m³, and the target organ was determined to be the lung, under the present experimental conditions in male rats.

Distinct Functions of Autoantibodies Against Interferon in Systemic Lupus Erythematosus: A Comprehensive Analysis of Anticytokine Autoantibodies in Common Rheumatic Diseases

OBJECTIVE

Anticytokine autoantibodies occur across a range of hematologic, pulmonary, and infectious diseases. However, systematic investigation of their presence and significance in autoimmune diseases is lacking. This study was undertaken to examine the distinct functions of anticytokine autoantibodies in patients with systemic lupus erythematosus (SLE) compared to patients with other rheumatic diseases and healthy controls.

METHODS

Serum samples from patients with SLE (n = 199), patients with primary Sjögren's syndrome (SS) (n = 150), patients with rheumatoid arthritis (RA) (n = 149), and healthy controls (n = 200) were screened for 24 anticytokine autoantibodies using a multiplex bead-based assay. To evaluate the biologic activity of anticytokine autoantibodies, their ability to block cytokine-induced signal transduction or protein expression was measured. RNA sequencing was performed on whole blood in a subset of healthy controls and patients with SLE.

RESULTS

Patients with SLE and those with SS had a striking excess of autoantibodies against interferons and the interferon-responsive chemokine interferon-inducible protein 10 (IP-10). Only autoantibodies against type I interferon, interleukin-12 (IL-12), and IL-22 exhibited neutralizing activity. In SLE, the presence of anti-interferon-γ autoantibodies was correlated with more severe disease activity, higher levels of anti-double-stranded DNA antibodies, and elevated expression of interferon-α/β-inducible genes. Conversely, in SLE patients with blocking anti-interferon-α autoantibodies, the type I interferon gene expression signature was normalized. Anti-type III interferon autoantibodies (λ2, λ3) and anti-IP-10 autoantibodies were newly recognized in SLE patient serum, and autoantibodies against macrophage-colony stimulating factor, IL-4, IL-7, IL-17, and IL-22, none of which have been previously identified in rheumatic conditions, were discovered.

CONCLUSION

Anticytokine autoantibodies are associated with distinct patterns of disease in SLE, SS, and RA. Anti-interferon autoantibodies are overrepresented in patients with SLE and those with SS, and fall into distinct functional classes, with only a subset of anti-type I interferon antibodies exhibiting neutralizing activity. Anti-interferon-γ autoantibodies are correlated with increased disease activity and interferon-related gene expression, suggesting that such autoantibodies may contribute to the pathogenesis of SLE.

A newly identified novel variant in the CSF2RA gene in a child with pulmonary alveolar proteinosis: a case report

BACKGROUND

The congenital form of pulmonary alveolar proteinosis due to colony stimulating factor 2 receptor alpha gene mutations is a rare disease with only a few cases reported worldwide. In this study we report a new case of pulmonary alveolar proteinosis with a novel variant in colony stimulating factor 2 receptor alpha gene.

CASE PRESENTATION

A 5-year-old Saudi boy presented with a history of progressive dyspnea over 6 months; he was diagnosed as having pulmonary alveolar proteinosis. A molecular study revealed a novel variation in colony stimulating factor 2 receptor alpha gene. His clinical condition showed significant improvement after whole lung lavage.

CONCLUSIONS

This case has the typical presentation of congenital pulmonary alveolar proteinosis due to colony stimulating factor 2 receptor alpha defect with a novel variant in this gene likely to be pathogenic.

Pulmonary Alveolar Proteinosis in Association with Secondary Hemophagocytic Lymphohistiocytosis

Pulmonary alveolar proteinosis (PAP) is a rare diffuse lung disease in the pediatric population. There are currently few cases documenting hemophagocytic lymphohistiocytosis as a cause for secondary PAP. We describe an ex-preterm child with secondary hemophagocytic lymphohistiocytosis, complicated by PAP and hypoxemic respiratory failure.

Twenty-eight-day repeated inhalation toxicity study of nano-sized lanthanum oxide in male sprague-dawley rats

Although the use of lanthanum has increased in field of high-tech industry worldwide, potential adverse effects to human health and to the environment are largely unknown. The present study aimed to investigate the potential toxicity of nano-sized lanthanum oxide (La₂ O₃ ) following repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed nose-only to nano-sized La₂ O₃ for 28 days (5 days/week) at doses of 0, 0.5, 2.5, and 10 mg/m³ . In the experimental period, we evaluated treatment-related changes including clinical signs, body weight, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology findings. We also analyzed lanthanum distribution in the major organs and in the blood, bronchoalveolar lavage fluids (BALF), and oxidative stress in lung tissues. Lanthanum level was highest in lung tissues and showed a dose-dependent relation. Alveolar proteinosis was observed in all treatment groups and was accompanied by an increase in lung weight; moreover, lung inflammation was observed in the 2.5 mg/m³ and higher dose groups and was accompanied by an increase in white blood cells. In the BALF, total cell counts including macrophages and neutrophils, lactate dehydrogenase, albumin, nitric oxide, and tumor necrosis factor-alpha increased significantly in all treatment groups. Furthermore, these changes tended to deteriorate in the 10 mg/m³ group at the end of the recovery period. In the present experimental conditions, we found that the lowest-observed-adverse-effect level of nano-sized La₂ O₃ was 0.5 mg/m³ in male rats, and the target organ was the lung. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1226-1240, 2017.

Quantitative assessment of Pulmonary Alveolar Proteinosis (PAP) with ultra-dose CT and correlation with Pulmonary Function Tests (PFTs)

Background

The purpose of this study was to investigate whether ultra-low-dose chest computed tomography (CT) can be used for visual assessment of CT features in patients with pulmonary alveolar proteinosis (PAP) and to evaluate the relationship between the quantitative analysis of the ultra-low-dose CT scans and the pulmonary function tests (PFTs).

Methods

Thirty-eight patients (mean [SD] age, 44.47 [12.28] years; 29 males, 9 females) with PAP were enrolled and subjected to two scans each with low-dose CT (reference parameters: 120 kV and 50 mAs) and ultra-low-dose CT (reference parameters, 80 kV, 25 mAs). Images were reconstructed via filtered back projection (FBP) for low-dose CT and iterative reconstruction (IR) for ultra-low-dose CT. All patients underwent PFT. The Visual analysis for ground glass opacity (GGO) is performed. The quantitative CT and PFT results were analyzed by canonical correlations.

Results

The mean body mass index (BMI) was 25.37±3.26 kg/m². The effective radiation doses were 2.30±0.46 and 0.24±0.05 mSv for low-dose and ultra-low-dose CT, respectively. The size-specific dose estimates were 5.81±0.81 and 0.62±0.09 mSv for low-dose and ultra-low-dose CT. GGOs and interlobular septal thickening were observed bilaterally in all patients. The average visual GGO score was lower in the upper field (2.67±1.24) but higher in the middle and lower fields (3.08±1.32 and 3.08±0.97, respectively). The average score for the whole lung was 2.94±1.19. There is a significant correlation between PFTs and quantitative of ultra-low-dose CT (canonical loading = 0.78).

Conclusions

Ultra-low-dose CT has the potential to quantify the lung parenchyma changes of PAP. This technique could provide a sensitive and objective assessment of PAP and has good relation with PFTs. In addition, the radiation dose of ultra-low-dose CT was very low.

Phase 1b randomized, double-blind study of namilumab, an anti-granulocyte macrophage colony-stimulating factor monoclonal antibody, in mild-to-moderate rheumatoid arthritis

Background

Namilumab (AMG203) is an immunoglobulin G1 monoclonal antibody that binds with high affinity to the GM-CSF ligand. This was a phase 1b, randomized, double-blind study (PRIORA) to assess namilumab in active, mild-to-moderate rheumatoid arthritis (RA). The primary outcome was the safety and tolerability of repeated subcutaneous injections of namilumab in patients with mild-to-moderate RA.

Methods

Adults with mild-to-moderate RA on stable methotrexate doses for ≥12 weeks were eligible. Patients received three subcutaneous injections of namilumab 150 or 300 mg, or placebo on days 1, 15, and 29, with 12 weeks’ follow-up. Primary objective was safety/tolerability.

Results

Patients in cohort 1 were randomized to namilumab 150 mg (n = 8) or placebo (n = 5). In cohort 2, patients were randomized to namilumab 300 mg (n = 7) or placebo (n = 4). Incidence of treatment-emergent adverse events (TEAEs) was similar across the three groups (namilumab 150 mg: 63%; namilumab 300 mg: 57%; placebo: 56%). TEAEs in ≥10% of patients were nasopharyngitis (17%) and exacerbation/worsening of RA (13%). No anti-namilumab antibodies were detected. The pharmacokinetics of namilumab were linear and typical of a monoclonal antibody with subcutaneous administration. In a post hoc efficacy, per protocol analysis (n = 21), patients randomized to namilumab showed greater improvement in Disease Activity Score 28 (erythrocyte sedimentation rate and C-reactive protein [CRP]), swelling joint counts and tender joint counts compared with placebo. Difference in mean DAS28-CRP changes from baseline between namilumab and placebo favored namilumab at both doses and at all time points. In addition area under the curve for DAS28-CRP was analyzed as time-adjusted mean change from baseline. A significant improvement in DAS28-CRP was shown with namilumab (150 and 300 mg groups combined) compared with placebo at day 43 (p = 0.0117) and also 8 weeks after last dosing at day 99 (p = 0.0154).

Conclusions

Subcutaneous namilumab was generally well tolerated. Although namilumab demonstrated preliminary evidence of efficacy, patient numbers were small; phase 2 studies are ongoing.

Trial registration

ClinicalTrials.gov, NCT01317797. Registered 18 February 2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1267-3) contains supplementary material, which is available to authorized users.

ABCG1 regulates pulmonary surfactant metabolism in mice and men

Idiopathic pulmonary alveolar proteinosis (PAP) is a rare lung disease characterized by accumulation of surfactant. Surfactant synthesis and secretion are restricted to epithelial type 2 (T2) pneumocytes (also called T2 cells). Clearance of surfactant is dependent upon T2 cells and macrophages. ABCG1 is highly expressed in both T2 cells and macrophages. ABCG1-deficient mice accumulate surfactant, lamellar body-loaded T2 cells, lipid-loaded macrophages, B-1 lymphocytes, and immunoglobulins, clearly demonstrating that ABCG1 has a critical role in pulmonary homeostasis. We identify a variant in the ABCG1 promoter in patients with PAP that results in impaired activation of ABCG1 by the liver X receptor α, suggesting that ABCG1 basal expression and/or induction in response to sterol/lipid loading is essential for normal lung function. We generated mice lacking ABCG1 specifically in either T2 cells or macrophages to determine the relative contribution of these cell types on surfactant lipid homeostasis. These results establish a critical role for T2 cell ABCG1 in controlling surfactant and overall lipid homeostasis in the lung and in the pathogenesis of human lung disease.

Elderly-onset hereditary pulmonary alveolar proteinosis and its cytokine profile

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare lung disease characterized by surfactant accumulation, and is caused by disruption of granulocyte/macrophage colony-stimulating factor (GM-CSF) signaling. Abnormalities in CSF2 receptor alpha (CSF2RA) were reported to cause pediatric hereditary PAP. We report here the first case of CSF2RA-mutated, elderly-onset hereditary (h) PAP.

CASE PRESENTATION

The patient developed dyspnea on exertion, and was diagnosed with PAP at the age of 77 years, based on findings from chest computed tomography scan and bronchoalveolar lavage. She tested negative for GM-CSF autoantibodies, with no underlying disease. Her serum GM-CSF level was elevated (91.3 pg/mL), indicating GM-CSF signaling impairment and genetic defects in the GM-CSF receptor. GM-CSF-stimulated phosphorylation in signal transducer and activator of transcription 5 (STAT5) was not observed, and GM-CSF-Rα expression was defective in her blood cells. Genetic screening revealed a homozygous, single-base C > T mutation at nt 508-a nonsense mutation that yields a stop codon (Q170X)-in exon 7 of CSF2RA. High-resolution analysis of single nucleotide polymorphism array confirmed a 22.8-Mb loss of heterozygosity region in Xp22.33p22.11, encompassing the CSF2RA gene. She was successfully treated with whole lung lavage (WLL), which reduced the serum levels of interleukin (IL)-2, IL-5, and IL-17, although IL-3 and M-CSF levels remained high.

CONCLUSIONS

This is the first known report of elderly-onset hPAP associated with a CSF2RA mutation, which caused defective GM-CSF-Rα expression and impaired signaling. The analyses of serum cytokine levels during WLL suggested that GM-CSF signaling might be compensated by other signaling pathways, leading to elderly-onset PAP.

Trametes polyzona, an emerging filamentous basidiomycete in Réunion Island

We describe two serious Trametes polyzona pulmonary infections, which occurred in Réunion Island, in critically ill patients. The identification was performed using sequencing of the internal transcribed spacer region of ribosomal DNA and D1/D2 region of 28S rDNA. In one case, the significance of T. polyzona in the pathological process was certain, proven by histopathological evidence of fungal lung infection. T. polyzona, an emerging filamentous basidiomycete, prevalent in tropical areas, has not been described so far in human infections.

Serum KL-6 in pulmonary alveolar proteinosis: China compared historically with Germany and Japan

BACKGROUND

KL-6 is a biomarker of the severity of pulmonary alveolar proteinosis (PAP). We noticed a significant difference in the mean serum KL-6 level between Japanese and Caucasian patients. To assess the clinical value of serum KL-6 in Chinese PAP patients, and to compare the differences in serum KL-6 levels in Chinese patients and patients of other ethnicities.

METHODS

From 2014-2016, we prospectively examined 37 Chinese Han patients with PAP, measured their serum KL-6 levels, evaluated the correlation between initial KL-6 levels and clinical variables, and compared our results with studies from Japan and Germany (similar methods were used). We searched dbSNP for the MUC1 568 (rs4072037) genotype or allele frequency distributions in China, Japan, and Germany.

RESULTS

Initial serum KL-6 levels were significantly correlated with baseline PaO₂, A-aDO₂, DLCO, FVC, and LDH levels (all P<0.001). Compared with Chinese PAP patients, the mean serum KL-6 level was significantly lower in German PAP patients (P<0.001) but not in Japanese PAP patients (P>0.4). In the rs4072037 allele frequency distributions, the frequency of the A/A genotype was significantly higher while that of the G/G genotype was significantly lower in Chinese and Japanese cohorts than in Caucasian cohorts (both P<0.001).

CONCLUSIONS

Serum KL-6 can be used as a biological indicator for disease monitoring in Chinese patients. The difference in serum KL-6 level among Chinese, German, and Japanese PAP patients may be associated with the distribution of the rs4072037 genotype.

GM-CSF Autoantibody-positive Pulmonary Alveolar Proteinosis with Simultaneous Myeloproliferative Neoplasm

Pulmonary alveolar proteinosis (PAP) is classified as autoimmune, secondary, or genetic. We herein describe a 69-year-old man with autoimmune PAP, simultaneously diagnosed with myeloproliferative neoplasm (MPN). Two years after the diagnosis, the MPN progressed to acute myeloid leukemia, and the patient died from an alveolar hemorrhage during remission induction chemotherapy. Throughout the clinical course, no progression of PAP was observed, despite the progression to leukemia. There are few reports of autoimmune PAP with hematological malignancy, and this case demonstrated that an evaluation for GM-CSF autoantibodies is important for distinguishing the autoimmune and secondary forms of PAP, even if the patient has hematological malignancy.

Whole Lung Lavage Treatment of Chinese Patients with Autoimmune Pulmonary Alveolar Proteinosis: A Retrospective Long-term Follow-up Study

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare lung disease, the most common type of which is autoimmune PAP. The gold standard therapy for PAP is whole lung lavage (WLL). Few studies have reported the optimal technique with which to evaluate the response to WLL. In this study, we aimed to identify parameters with which to assess the need for repeat WLL during a long-term 8-year follow-up.

METHODS

We conducted a retrospective analysis of 120 patients with autoimmune PAP with 80 of whom underwent WLL. Physiologic, serologic, and radiologic features of the patients were analyzed during an 8-year follow-up after the first WLL treatment.

RESULTS

Of the 40 patients without any intervention, 39 patients either achieved remission or remained stable and only one died of pulmonary infection. Of the 56 patients who underwent WLL for 1 time, 55 remained free from a second WLL and 1 patient died of cancer. Twenty-four required additional treatments after their first WLL. The baseline PaO 2 (P = 0.000), PA-aO 2 (P = 0.000), shunt fraction rate (P = 0.001), percent of predicted normal diffusing capacity of the lung for carbon monoxide (DLCO%Pred) (P = 0.016), 6-min walk test (P = 0.013), carcinoembryonic antigen (CEA) (P = 0.007), and neuron-specific enolase (NSE) (P = 0.003) showed significant differences among the three groups. The need for a second WLL was significantly associated with PaO 2 (P = 0.000), CEA (P = 0.050) , the 6-minute walk test (P = 0.026), and DLCO%Pred (P = 0.041). The DLCO%Pred on admission with a cut-off value of 42.1% (P = 0.001) may help to distinguish whether patients with PAP require a second WLL.

CONCLUSIONS

WLL is the optimal treatment method for PAP and provides remarkable improvements for affected patients. The DLCO%Pred on admission with a cut-off value of 42.1% may distinguish whether patients with PAP require a second WLL.

Death Due to Pulmonary Alveolar Proteinosis

Presented are 2 cases of death from pulmonary alveolar proteinosis (PAP). Within the past 2 years, there have been 2 cases of rare nonneoplastic lung disease that consists of the filling of the alveoli of the lung by a periodic acid-Schiff stain-positive lipoproteinaceous material. This condition bears a certain resemblance to interstitial lung disease and/or Pneumocystitis jirovecci infection of the lungs. The presented cases were clinically diagnosed as interstitial lung disease. In the first case presented, the decedent was admitted to hospital with diagnosis of pneumonia but died in hospital despite observation and treatment. Autopsy examination revealed that instead of an infection, there was amorphous granular eosinophilic proteinaceous fluid in irregular clumps, with scattered foamy macrophages and cholesterol clefts and cracks in the lung alveoli. The second case was suspected of electrocution. There were no findings pointing to or against the possibility of electrocution, whereas the alveoli and terminal bronchioles were filled with amorphous granular eosinophilic lipoproteinaceous substance. The alveolar structure was well preserved, and the interstitium had no or mild chronic inflammatory cells. In both cases, the lipoproteinaceous material stained deep pink with periodic acid-Schiff stain. The gross and microscopic examination in the second case also signified pulmonary alveolar proteinosis.The following report describes 2 cases of this uncommon disorder, with cause of death confirmed by postmortem examination.

MAIT cells promote inflammatory monocyte differentiation into dendritic cells during pulmonary intracellular infection

Cowley and Meierovics show that mucosa-associated invariant T (MAIT) cells promote the differentiation of monocytes into monocyte-derived dendritic cells during Francisella tularensis LVS pulmonary infection.

Mucosa-associated invariant T (MAIT) cells are a unique innate T cell subset that is necessary for rapid recruitment of activated CD4⁺ T cells to the lungs after pulmonary F. tularensis LVS infection. Here, we investigated the mechanisms behind this effect. We provide evidence to show that MAIT cells promote early differentiation of CCR2-dependent monocytes into monocyte-derived DCs (Mo-DCs) in the lungs after F. tularensis LVS pulmonary infection. Adoptive transfer of Mo-DCs to MAIT cell–deficient mice (MR1^−/− mice) rescued their defect in the recruitment of activated CD4⁺ T cells to the lungs. We further demonstrate that MAIT cell–dependent GM-CSF production stimulated monocyte differentiation in vitro, and that in vivo production of GM-CSF was delayed in the lungs of MR1^−/− mice. Finally, GM-CSF–deficient mice exhibited a defect in monocyte differentiation into Mo-DCs that was phenotypically similar to MR1^−/− mice. Overall, our data demonstrate that MAIT cells promote early pulmonary GM-CSF production, which drives the differentiation of inflammatory monocytes into Mo-DCs. Further, this delayed differentiation of Mo-DCs in MR1^−/− mice was responsible for the delayed recruitment of activated CD4⁺ T cells to the lungs. These findings establish a novel mechanism by which MAIT cells function to promote both innate and adaptive immune responses.

Lung surfactant metabolism: early in life, early in disease and target in cell therapy

Lung surfactant is a complex mixture of lipids and proteins lining the alveolar epithelium. At the air-liquid interface, surfactant lowers surface tension, avoiding alveolar collapse and reducing the work of breathing. The essential role of lung surfactant in breathing and therefore in life, is highlighted by surfactant deficiency in premature neonates, which causes neonatal respiratory distress syndrome and results in early death after birth. In addition, defects in surfactant metabolism alter lung homeostasis and lead to disease. Special attention should be paid to two important key cells responsible for surfactant metabolism: alveolar epithelial type II cells (AE2C) and alveolar macrophages (AM). On the one hand, surfactant deficiency coming from abnormal AE2C function results in high surface tension, promoting alveolar collapse and mechanical stress in the epithelium. This epithelial injury contributes to tissue remodeling and lung fibrosis. On the other hand, impaired surfactant catabolism by AM leads to accumulation of surfactant in air spaces and the associated altered lung function in pulmonary alveolar proteinosis (PAP). We review here two recent cell therapies that aim to recover the activity of AE2C or AM, respectively, therefore targeting the restoring of surfactant metabolism and lung homeostasis. Applied therapies successfully show either transplantation of healthy AE2C in fibrotic lungs, to replace injured AE2C cells and surfactant, or transplantation of bone marrow-derived macrophages to counteract accumulation of surfactant lipid and proteinaceous material in the alveolar spaces leading to PAP. These therapies introduce an alternative treatment with great potential for patients suffering from lung diseases.

Whole lung lavage therapy for pulmonary alveolar proteinosis: a global survey of current practices and procedures

BACKGROUND

Whole lung lavage (WLL) is the current standard of care treatment for patients affected by pulmonary alveolar proteinosis (PAP). However, WLL is not standardized and international consensus documents are lacking. Our aim was to obtain a factual portrayal of WLL as currently practiced with respect to the procedure, indications for its use, evaluation of therapeutic benefit and complication rate.

METHODS

A clinical practice survey was conducted globally by means of a questionnaire and included 27 centers performing WLL in pediatric and/or adult PAP patients.

RESULTS

We collected completed questionnaires from 20 centres in 14 countries, practicing WLL in adults and 10 centers in 6 countries, practicing WLL in pediatric patients. WLL is almost universally performed under general anesthesia, with a double-lumen endobronchial tube in two consecutive sessions, with an interval of 1-2 weeks between sessions in approximately 50 % of centres. The use of saline warmed to 37 °C, drainage of lung lavage fluid by gravity and indications for WLL therapy in PAP were homogenous across centres. There was great variation in the choice of the first lung to be lavaged: 50 % of centres based the choice on imaging, whereas 50 % always started with the left lung. The choice of position was also widely discordant; the supine position was chosen by 50 % of centres. Other aspects varied significantly among centres including contraindications, methods and timing of follow up, use of chest percussion, timing of extubation following WLL and lung isolation and lavage methods for small children. The amount of fluid used to perform the WLL is a critical aspect. Whilst a general consensus exists on the single aliquot of fluid for lavage (around 800 ml of warm saline, in adults) great variability exists in the total volume instilled per lung, ranging from 5 to 40 liters, with an average of 15.4 liters/lung.

CONCLUSIONS

This international survey found that WLL is safe and effective as therapy for PAP. However these results also indicate that standardization of the procedure is required; the present survey represents the a first step toward building such a document.

Recurrence of pulmonary alveolar proteinosis after bilateral lung transplantation in a patient with a nonsense mutation in CSF2RB

Hereditary pulmonary alveolar proteinosis (PAP) caused by mutations in CSF2RA or CSF2RB, which encode GM-CSF receptor α and β respectively, is a rare disease. Although some experimental therapeutic strategies have been proposed, no clinical evidence has yet been reported. We herein describe the clinical course and recurrence of hereditary PAP after lung transplantation. A 36-year-old woman developed PAP of unknown etiology. She underwent bilateral lung transplantation from living donors at the age of 42 years because of severe respiratory failure complicated by pulmonary fibrosis. However, PAP recurred after 9 months, and we found that donor-origin alveolar macrophages had been almost completely replaced with recipient-origin macrophages. We performed a genetic analysis and identified a point deletion in the CSF2RB gene that caused a GM-CSF receptor-mediated signaling defect. PAP progressed with fibrosis in both transplanted lungs, and the patient died of respiratory failure 5 years after the lung transplantation. Distinct from recent reports on pulmonary macrophage transplantation in mice, this case suggests that human alveolar macrophages might not maintain their population only by self-renewal but may depend on a supply of precursor cells from the circulation. Bone marrow transplantation should be considered for treatment of severe PAP with GM-CSF receptor gene deficiency.