Pulmonary alveolar proteinosis

A comprehensive summary of disease variants implicated in metal allergy

Allergic disease represents one of the most prominent global public health crises of the 21^st century. Although many different substances are known to produce hypersensitivity responses, metals constitute one of the major classes of allergens responsible for a disproportionately large segment of the total burden of disease associated with allergy. Some of the most prevalent forms of metal allergy - including allergic contact dermatitis - are well-recognized; however, to our knowledge, a comprehensive review of the many unique disease variants implicated in human cases of metal allergy is not available within the current scientific literature. Consequently, the main goal in composing this review was to (1) generate an up-to-date reference document containing this information to assist in the efforts of lab researchers, clinicians, regulatory toxicologists, industrial hygienists, and other scientists concerned with metal allergy and (2) identify knowledge gaps related to disease. Accordingly, an extensive review of the scientific literature was performed - from which, hundreds of publications describing cases of metal-specific allergic responses in human patients were identified, collected, and analyzed. The information obtained from these articles was then used to compile an exhaustive list of distinctive dermal/ocular, respiratory, gastrointestinal, and systemic hypersensitivity responses associated with metal allergy. Each of these disease variants is discussed briefly within this review, wherein specific metals implicated in each response type are identified, underlying immunological mechanisms are summarized, and major clinical presentations of each reaction are described.Abbreviations: ACD: allergic contact dermatitis, AHR: airway hyperreactivity, ASIA: autoimmune/ autoinflammatory syndrome induced by adjuvants, BAL: bronchoalveolar lavage, CBD: chronic beryllium disease, CTCL: cutaneous T-cell lymphoma, CTL: cytotoxic T-Lymphocyte, DRESS: drug reaction with eosinophilia and systemic symptoms, GERD: gastro-esophageal reflux disease, GI: gastrointestinal, GIP: giant cell interstitial pneumonia, GM-CSF: granulocyte macrophage-colony stimulating factor, HMLD: hard metal lung disease, HMW: high molecular weight, IBS: irritable bowel syndrome, Ig: immunoglobulin, IL: interleukin, LMW: low molecular weight, PAP: pulmonary alveolar proteinosis, PPE: personal protective equipment, PRR: pathogen recognition receptor, SLE: systemic lupus erythematosus, SNAS: systemic nickel allergy syndrome, Th: helper T-cell, UC: ulcerative colitis, UV: ultraviolet.

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 Role of GM-CSF Autoantibodies in Infection and Autoimmune Pulmonary Alveolar Proteinosis: A Concise Review

Autoantibodies to multiple cytokines have been identified and some, including antibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF), have been associated with increased susceptibility to infection. High levels of GM-CSF autoantibodies that neutralize signaling cause autoimmune pulmonary alveolar proteinosis (aPAP), an ultrarare autoimmune disease characterized by accumulation of excess surfactant in the alveoli, leading to pulmonary insufficiency. Defective GM-CSF signaling leads to functional deficits in multiple cell types, including macrophages and neutrophils, with impaired phagocytosis and host immune responses against pulmonary and systemic infections. In this article, we review the role of GM-CSF in aPAP pathogenesis and pulmonary homeostasis along with the increased incidence of infections (particularly opportunistic infections). Therefore, recombinant human GM-CSF products may have potential for treatment of aPAP and possibly other infectious and pulmonary diseases due to its pleotropic immunomodulatory actions.

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.

Reversible sirolimus-induced pulmonary alveolar proteinosis in a renal transplant patient

Pulmonary alveolar proteinosis (PAP) is characterized by accumulation of surfactant-like lipoprotein material within distal bronchioles and alveoli due to impaired clearance. Clinically, PAP presents with dyspnea and cough. A 58-year-old Hispanic man presented with 6 months of productive cough, weight loss, and progressively worsening dyspnea. He reported a long history of poorly controlled type 2 diabetes that led to diabetic nephropathy. The patient had a strong passive smoking history for over 30 years and exposure to woodsmoke. He had pulmonary tuberculosis in 2007 and 2012. In 2011, he was diagnosed with renal failure, was dialyzed for a year, and received a renal transplant in 2012. His posttransplant medication regimens included tacrolimus, mycophenolic acid, and prednisone. Six months after the transplant, he suffered graft rejection, managed with steroids and switching from tacrolimus to sirolimus. His physical examination demonstrated scattered inspiratory crackles, and a chest X-ray showed bilateral perihilar ground-glass opacities. PAP was diagnosed through lung biopsy, which showed eosinophilic granular infiltrate withing the alveoli. Sirolimus was switched back to tacrolimus 2 mg in September 2018. PAP diagnosis included hematoxylin and eosin and PAS. Clinical follow-up included oxygen saturation with pulse oximeter and chest X-rays. A 2-month follow-up showed only partial improvement in both symptoms and radiological findings. In January 2019, a follow-up showed complete radiological and symptomatologic resolution. After 5 months, the patient remains asymptomatic with adequate exertion tolerance. PAP remains a diagnosis of exclusion in patients undergoing immunomodulatory therapy with sirolimus and pulmonary symptoms. Reversal can be achieved by switching agents.

Neonatal Lung Disorders: Pattern Recognition Approach to Diagnosis

OBJECTIVE

Lung disease is a common indication for neonates to require medical attention, and neonatal chest radiographs are among the most common studies interpreted by pediatric radiologists. Radiographic features of many neonatal lung disorders overlap, and it may be difficult to differentiate among conditions.

CONCLUSION

This review presents an up-to-date practical approach to the radiologic diagnosis of neonatal lung disorders, with a focus on pattern recognition and consideration of clinical history, patient age, and symptoms.

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.

Particle-induced Pulmonary Alveolar Proteinosis and Subsequent Inflammation and Fibrosis: A Toxicologic and Pathologic Review

This review analyzes the published data on cases of pulmonary alveolar proteinosis (PAP) in workers inhaling crystalline aluminum, indium, silicon, and titanium particles and possible sequelae, that is, inflammation and fibrosis, and compares these findings with those from animal experiments. In inhalation studies in rodents using crystalline indium and gallium compounds, pronounced PAP followed by inflammation and fibrosis down to very low concentration ranges have been reported. Crystalline aluminum, silicon, and titanium compounds also induced comparable pulmonary changes in animals, though at higher exposure levels. Laboratory animal species appear to react to the induction of PAP with varying degrees of sensitivity. The sensitivity of humans to environmental causes of PAP seems to be relatively low. Up to now, no cases of PAP, or other pulmonary diseases in humans, have been described for gallium compounds. However, a hazard potential can be assumed based on the results of animal studies. Specific particle properties, responsible for the induction of PAP and its sequelae, have not been identified. This review provides indications that, both in animal studies and in humans, PAP is not often recognized due to the absence of properly directed investigation or is concealed behind other forms of lung pathology.

Metabolic Functions of the Lung, Disorders and Associated Pathologies

The primary function of the lungs is gas exchange. Approximately 400 million years ago, the Earth's atmosphere gained enough oxygen in the gas phase for the animals that emerged from the sea to breathe air. The first lungs were merely primitive air sacs with a few vessels in the walls that served as accessory organs of gas exchange to supplement the gills. Eons later, as animals grew accustomed to a solely terrestrial life, the lungs became highly compartmentalized to provide the vast air-blood surface necessary for O2 uptake and CO2 elimination, and a respiratory control system was developed to regulate breathing in accordance with metabolic demands and other needs. With the evolution and phylogenetic development, lungs were taking a variety of other specialized functions to maintain homeostasis, which we will call the non-respiratory functions of the lung and that often, and by mistake, are believed to have little or no connection with the replacement gas. In this review, we focus on the metabolic functions of the lung, perhaps the least known, and mainly, in the lipid metabolism and blood-adult lung vascular endothelium interaction. When these functions are altered, respiratory disorders or diseases appear, which are discussed concisely, emphasizing how they impact the most important function of the lungs: external respiration.

Lung Transplant Recipient with Pulmonary Alveolar Proteinosis

Pulmonary alveolar proteinosis (PAP) is a progressive lung disease characterized by accumulated surfactant-like lipoproteinaceous material in the alveoli and distal bronchioles. This accumulation is the result of impaired clearance by alveolar macrophages. PAP has been described in 11 solid organ transplant recipients, 9 of whom were treated with mammalian target of rapamycin inhibitors. We report a case of a lung transplant recipient treated with prednisone, mycophenolate mofetil (MMF), and tacrolimus who ultimately developed PAP, which worsened when MMF was replaced with everolimus.

The First Case of Pulmonary Alveolar Proteinosis With Small Cell Lung Carcinoma

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disease characterized by alveolar accumulation of surfactant lipids and proteins. It is usually autoimmune and secondary to hematologic malignancy or infection. To date, only 5 case reports of PAP associated with lung cancers, including 2 cases of squamous cell carcinoma and 3 cases of adenocarcinoma, have been published. To the best of our knowledge, no case of PAP with small cell lung carcinoma has been reported thus far. We herein report the first case of PAP associated with small cell lung carcinoma.

Treatment of Adult Primary Alveolar Proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by the accumulation of surfactant-like lipoproteinaceous material in the distal air spaces and terminal bronchi, which may lead to impaired gas exchange. This accumulation of surfactant is due to decreased clearance by the alveolar macrophages. Its primary, most common form, is currently considered an autoimmune disease. Better knowledge of the causes of PAP have led to the emergence of alternatives to whole lung lavage, although this is still considered the treatment of choice. Most studies are case series, often with limited patient numbers, so the level of evidence is low. Since the severity of presentation and clinical course are variable, not all patients will require treatment. Due to the low level of evidence, some objective criteria based on expert opinion have been arbitrarily proposed in an attempt to define in which patients it is best to initiate treatment.

Characterization of CSF2RA mutation related juvenile pulmonary alveolar proteinosis

Background

Juvenile pulmonary alveolar proteinosis (PAP) due to CSF2RA mutations is a rare disorder with only a few cases described worldwide.

Methods

We identified nine children with severe diffuse interstitial lung disease due to CSF2RA mutations. Clinical course, diagnostic findings and treatment were evaluated and correlated to the genotype. Functional impairment of the intracellular JAK/pStat5 signaling pathway was assessed using flow-cytometry of peripheral mononuclear cells (PBMC) and granulocytes.

Results

We identified six individuals with homozygous missense/nonsense/frameshift mutations and three individuals homozygous for a deletion of the complete CSF2RA gene locus. Overall, four novel mutations (c.1125 + 1G > A, duplication exon 8, deletion exons 2–13, Xp22.3/Yp11.3) were found. Reduced STAT5 phosphorylation in PBMC and granulocytes was seen in all cases examined (n = 6). Pulmonary symptoms varied from respiratory distress to clinically silent. Early disease onset was associated with a more severe clinical phenotype (p = 0.0092). No association was seen between severity of phenotype at presentation and future clinical course or extent of genetic damage. The clinical course was favorable in all subjects undergoing whole lung lavage (WLL) treatment.

Conclusions

Our cohort broadens the spectrum of knowledge about the clinical variability and genotype-phenotype correlations of juvenile PAP, and illustrates the favorable outcome of WLL treatment in severely affected patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-014-0171-z) contains supplementary material, which is available to authorized users.

Emerging cell and cytokine targets in rheumatoid arthritis

Despite major progress in the treatment of rheumatoid arthritis (RA), strong unmet medical need remains, as only a minor proportion of patients reach sustained clinical remission. New approaches are therefore necessary, and include manipulation of regulatory T cells, which might be able to restore the disturbed immune system and could even lead to a cure if this restored regulation were to prove sustainable. Logistical and conceptual problems, however, beset this attractive therapeutic approach, including difficulties with ex vivo expansion of cells, specificity of targeting and the optimal time point of administration. Therefore, alternative avenues are being investigated, such as targeting B-cell effector functions and newly identified proinflammatory cytokines. On the basis of success with B-cell depleting therapy using anti-CD20 agents, further treatment modalities are now exploring direct or indirect interference in B-cell-mediated immunity with the use of agents directed against other B-cell surface molecules. Novel approaches target intracellular B-cell signalling and regulatory B cells. New cytokine-directed therapies target important proinflammatory mediators such as GM-CSF, new members of the IL-1 family, IL-6 and its receptor, IL-17, IL-20, IL-21, IL-23 as well as synovium-specific targets. This article reviews these emerging cell and cytokine targets with special focus on biologic agents, some of which might reach the clinic soon whereas others will require considerable time in development. Nevertheless, these exciting new approaches will considerably enhance our repertoire in the battle against this potentially devastating disease.

Pulmonary alveolar proteinosis: report of two cases in the West of Ireland with review of current literature

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare lung condition characterised by the accumulation of lipoproteinaceous surfactant material within alveolar airspaces resulting in clinical manifestations ranging from asymptomatic to severe respiratory failure. Three disease subtypes are recognised: autoimmune, secondary and congenital.

METHODS

We describe two presentations of PAP in the West of Ireland with a review of the current literature.

RESULTS

Autoimmune PAP, associated with the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies, accounts for >90 % of cases. Treatment with whole lung lavage is the current standard of care. Novel therapies targeting alveolar macrophages (recombinant GM-CSF therapy) and anti-GM-CSF antibodies (rituximab, plasmapharesis) are under investigation.

CONCLUSIONS

This is a summary of available literature outlining current clinical practice in the diagnosis, management, and treatment of PAP. PAP should be considered in the differential diagnosis of any patient with a restrictive pulmonary defect. Without high clinical suspicion, this diagnosis can easily be missed.

Treatment of Acute Silicoproteinosis by Whole-Lung Lavage

Acute silicoproteinosis is a rare disease that occurs following a heavy inhalational exposure to silica dusts. Clinically, it resembles pulmonary alveolar proteinosis (PAP); silica exposure is thought to be a cause of secondary PAP. We describe a patient with biopsy-confirmed acute silicoproteinosis whose course was complicated by acute hypoxemic respiratory failure requiring mechanical ventilation. Without clinical improvement despite antibiotic and steroid treatment, the patient was scheduled for whole-lung lavage under general anesthesia. Anesthetic challenges included double-lumen tube placement and single-lung ventilation in a hypoxic patient, facilitating lung lavage, and protecting the contralateral lung from catastrophic spillage.