Update on Diagnosis and Treatment of Adult Pulmonary Alveolar Proteinosis

A patient journey map for people living with autoimmune pulmonary alveolar proteinosis

INTRODUCTION

Patients with autoimmune pulmonary alveolar proteinosis (PAP) face a complicated journey (physically, emotionally, and financially) to receive the correct diagnosis and treatment. We developed a patient journey map (PJM) to describe the experiences and needs of patients with autoimmune PAP in the USA.

METHODS

This PJM was developed in four stages: (1) analysis of existing literature; (2) patient advisory board meetings (n = 7); (3) an online survey (n = 19); and (4) a validation workshop (n = 6).

RESULTS

Four phases of the patient journey were identified: (1) symptoms and experience before diagnosis; (2) diagnosis; (3) treatment; and (4) ongoing monitoring. Patients reported heterogeneous and indirect diagnostic pathways, often waiting months or years for the correct diagnosis. The majority reported at least one misdiagnosis, most commonly pneumonia. Treatment pathways varied substantially, and current treatments and off-label therapies were frequently described as burdensome, emotionally taxing, and/or financially worrisome. Patients described their journey as an "emotional rollercoaster," especially during pre-diagnosis and treatment. Patients reported common barriers to care, particularly insurance problems and access to expert care. Patients specifically cited the need for improved education on autoimmune PAP within the medical community and increased help with insurance challenges related to current treatments.

CONCLUSIONS

This PJM provides insights on patients' journeys with autoimmune PAP. Patients reported inconsistent, burdensome, and circuitous journeys. This PJM provides the medical community with valuable information on patients' needs and increases awareness of this rare disease. Over time, these factors may improve diagnosis, treatment, and the holistic experience of patients with autoimmune PAP.

Fast-Track Extubation in a Patient Undergoing Whole Lung Lavage: A Case Report

ABSTRACT

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary pathology characterized by the accumulation of surfactant within type II alveolar epithelial cells. Whole lung lavage is the standard treatment for pulmonary alveolar proteinosis involving a large volume of fluid is infused into one lung and subsequently retrieved while the other lung is remains ventilated. Fast-tracking a patient undergoing whole lung lavage requires vigilant monitoring of arterial blood gases, fluid status, and respiratory mechanics. We report a case of a patient who underwent whole lung lavage for PAP, where early extubation was performed, avoiding the complications associated with prolonged mechanical ventilation.

A Comprehensive Outlook on Pulmonary Alveolar Proteinosis-A Review

Pulmonary alveolar proteinosis (PAP) is an ultra-rare disease caused by impaired pulmonary surfactant clearance due to the dysfunction of alveolar macrophages or their signaling pathways. PAP is categorized into autoimmune, congenital, and secondary PAP, with autoimmune PAP being the most prevalent. This article aims to present a comprehensive review of PAP classification, pathogenesis, clinical presentation, diagnostics, and treatment. The literature search was conducted using the PubMed database and a total of 67 articles were selected. The PAP diagnosis is usually based on clinical symptoms, radiological imaging, and bronchoalveolar lavage, with additional GM-CSF antibody tests. The gold standard for PAP treatment is whole-lung lavage. This review presents a summary of the most recent findings concerning pulmonary alveolar proteinosis, pointing out specific features that require further investigation.

Selective bronchial occlusion for the prevention of pneumothorax after transbronchial lung cryobiopsy in a pulmonary alveolar proteinosis patient: a case report

The diagnosis of pulmonary alveolar proteinosis (PAP) is based on biopsies. Compared with other methods of taking biopsies, transbronchial lung cryobiopsy (TBLC) has a higher diagnostic rate and the likelihood of pneumothorax. Selective bronchial occlusion (SBO) is an effective technique for treating intractable pneumothorax. However, there are no data available about SBO for the prevention of pneumothorax after TBLC in a PAP patient. A 49-year-old man complained of recurrent cough and tachypnea, and his symptoms did not fully resolve until the diagnosis was confirmed, and he was treated with whole lung lavage. Our patient was ultimately diagnosed with PAP by TBLC but not multiple tests for the bronchoalveolar lavage fluid (BALF). The patient was discharged quickly after whole lung lavage due to the fact that he did not develop pneumothorax under SBO. This case illustrates that TBLC is a supplementary examination for PAP, especially for those in whom BALF results fail to confirm a diagnosis. Moreover, our report highlights that SBO is necessary to effectively prevent pneumothorax during and after multiple TBLCs in PAP patients.

HLA-DRB1*14:54 Is Associated with Pulmonary Alveolar Proteinosis: A Retrospective Real-World Audit

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disease characterized by abnormal accumulation of pulmonary surfactant lipids in alveoli or terminal bronchioles, leading to increased infection risk and progressive respiratory failure. Approximately more than 90% of all cases are autoimmune PAP (aPAP). Since one of the predisposing factors has been identified as genes located within the major-histocompatibility-complex region, an investigation of human leukocyte antigen (HLA) alleles associated with the risk of aPAP is warranted.

METHODS

We retrospectively studied 60 patients pathologically diagnosed with PAP from 2019 to 2022. Patients were divided into the aPAP group or secondary PAP (sPAP) group according to their clinical information. Qualified DNA was extracted from the paraffin-embedded tissue of 28 patients, and the PCR-sequence-based typing method was used for HLA-DRB1 genotyping.

RESULTS

A similar HLA-DRB1 allele profile (including the HLA-DRB1*08:03) between the aPAP group and sPAP group was revealed, except that HLA-DRB1*14:54, which has never been reported in aPAP patients, was only detected in the aPAP group rather than the sPAP group (19.4% vs. 0.0%, p = 0.030). Under inhaled granulocyte-macrophage colony-stimulating factor therapy, more clinical remission was observed in HLA-DRB1*14:54 carriers rather than in HLA-DRB1*08:03 carriers (80.0% vs. 57.1%).

CONCLUSIONS

Our real-world study revealed for the first time that a population with HLA-DRB1*14:54 was subject to aPAP, and HLA-DRB1*14:54 might imply a response in aPAP patients to inhaled granulocyte-macrophage colony-stimulating factor in aPAP patients.

Unexpected diffuse lung lesions in a patient with pulmonary alveolar proteinosis: A case report

BACKGROUND

Pulmonary alveolar proteinosis (PAP) often presents nonspecifically and can be easily confused with: (1) Idiopathic interstitial lung fibrosis; (2) alveolar carcinoma; (3) pulmonary tuberculosis; and (4) other lung diseases such as viral pneumonia, mycoplasma pneumonia, and chlamydial pneumonia.

CASE SUMMARY

Diagnosis: In this case, a patient was diagnosed with PAP through transbronchial cryobiopsy (TBCB) and quantitative metagenomic next-generation sequencing, which confirmed the impairment of surfactant turnover as the underlying cause of PAP. Interventions: High-volume total lung lavage was performed for this patient. Outcomes: The patient's clinical condition had improved significantly by the 6-month follow-up, with a 92% finger oxygen saturation. A repeat chest computed tomography scan revealed scattered patchy ground-glass shadows in both lungs, which was consistent with alveolar protein deposition but with a lower density than in the radiograph from October 23, 2022.

CONCLUSION

TBCB has unique advantages in diagnosing atypical alveolar protein deposition, particularly for enabling the early detection of PAP. This information can help patients take preventive measures to prevent or halt PAP development by avoiding dusty environments and seeking treatment with total lung lavage and inhaled granulocyte macrophage colony-stimulating factor.

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.

A case of autoimmune pulmonary alveolar proteinosis with severe respiratory failure treated with segmental lung lavage and oral statin therapy

Pulmonary alveolar proteinosis (PAP) is a diffuse lung disease characterized by the accumulation of alveolar surfactants due to dysfunction of granulocyte-macrophage colony-stimulating factor-dependent cholesterol clearance. Whole-lung lavage is the current standard of care for PAP, but it can lead to the exacerbation of hypoxia. A medication targeting cholesterol homeostasis is a promising therapy for refractory PAP. We present a case of autoimmune PAP with severe hypoxia that was successfully treated with segmental lung lavage (SLL). Following SLL for disease relapse, statin treatment for dyslipidemia was started. After initiating statin treatment, the patient did not require bronchoalveolar lavage for 10 months.

Efficacy and safety of whole-lung lavage for pulmonary alveolar proteinosis: a protocol for a systematic review and meta-analysis

INTRODUCTION

Pulmonary alveolar proteinosis (PAP) is an ultrarare disorder characterised by the accumulation of alveolar surfactant and the dysfunction of alveolar macrophages that results in hypoxemic respiratory failure. Whole-lung lavage (WLL) is currently the primary therapy for PAP. However, systematic evaluation of the clinical efficacy of WLL is lacking. We aim to perform a systematic review and meta-analysis of existing evidence to support WLL for the clinical treatment of PAP.

METHODS AND ANALYSIS

We will search the PubMed (MEDLINE), Cochrane Library, Embase, Web of Science and Google Scholar databases from inception to December 2021 for observational studies using WLL for the treatment of PAP. Two authors will independently screen the eligible studies, assess the quality of the included papers and extract the required information. Review Manager V.5.4 will be used to perform the meta-analysis. We will evaluate the overall quality of evidence using the Grading of Recommendations, Assessment, Development and Evaluation approach. All steps of this protocol will be performed using the Cochrane Handbook for Preferred Reporting Items for Systematic Review and Meta-analysis statement.

ETHICS AND DISSEMINATION

This systematic review and meta-analysis will be based on published data. Therefore, ethical approval is not required. We will publish our results in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022306221 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022306221).

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.

Pulmonary storage

Interstitial lung diseases (ILDs) are not just a matter of scarring or inflammation in the lung tissue. The lungs can also serve as a repository for products that can be produced in excessive amounts in the human body as a result of disease. Geneticaly based dysfunctions of lysosomal enzymes, which leads to an unefficient degradation and transport of various macromolecules from lysosomes, are considered to be storage diseases sensu stricto. ILDs were described in patients with Gaucher disease, Niemann-Pick disease and Fabry disease. In a broader context, however, the accumulation of various substances in the lung tissue is also encountered in cases of pediatric pulmonary interstitial glycogenosis (PIG), alveolar lipoproteinosis or pulmonary amyloidosis. The cause of PIG is not clear. The disease was first described in 2002 and a lung tissue sample is required to establish this diagnosis. Even though PIG usually goes well in childhood and the patients difficulties spontaneously subside over time, the long-term prognosis of the patients is unknown. Alveolar lipoproteinoses can be acquired (e.g. after massive exposure to silica dust), autoimmune, but also genetically determined. Unlike lysosomal storage diseases, in the case of pulmonary alveolar lipoproteinosis, accumulation of abnormal macromolecules occurs only in the lungs of affected individuals. Similarly, amyloidosis is not a single disease, but a group of diseases with different etiopathogenesis, as a result of which amyloid - a group of different proteins with a distinctvive conformation, which can be deposited in various organs, including the lungs - is formed. The diagnosis of pulmonary alveolar lipoproteinosis is based on the typical appearance and biochemical composition of the fluid obtained by bronchoalveolar lavage, the diagnosis of amyloidosis is histological.