A rare and challenging case of a preterm neonate with clinical and radiological signs of respiratory distress syndrome (RDS) since the first hour of life but was refractory to its standard treatment regimes like surfactant therapy and ventilation. Postmortem lung biopsy led us to the diagnosis of congenital pulmonary alveolar proteinosis (PAP). It occurs due to the aggregation of abnormal surfactant proteins and lipids in the alveoli, which hampers gas diffusion across the alveoli. It presents as respiratory distress at birth, and its diagnosis is often missed due to its resemblance with RDS. Although the exact etiology remains elusive, mutations in genes encoding surfactant and granulocyte-macrophage colony-stimulating factor (GM-CSF) pathway components have been implicated in the pathogenesis of PAP. Treatment options are limited and only supportive. Among all these, whole-lung lavage is the most widely used management modality but with limited success in neonates.

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.

UNASSIGNED: Lysinuric protein intolerance (LPI) is a rare genetic disorder caused by mutations in the solute carrier family 7A member 7 (SLC7A7) gene.
UNASSIGNED: We presented two siblings with LPI, carrying novel mutations of c.776delT (p.L259Rfs*18) and c.155G>T (p.G52V) in SLC7A7. The younger sibling, preferring protein-rich foods, showed severe symptoms, including alveolar proteinosis, macrophage activation syndrome, severe diarrhea, and disturbance of consciousness with involuntary movements. In contrast, the elder sibling only had mild symptoms, likely due to aversion to protein-rich food since toddler age.
UNASSIGNED: LPI is a congenital genetic metabolic disease with multi-system involvement. Initiating appropriate protein-restricted diet therapy as soon as possible could help prevent the progression of LPI.

Secondary pulmonary alveolar proteinosis (SPAP) is one of the diffuse parenchymal lung diseases, and the utility and safety of transbronchial lung cryobiopsy (TBLC) for diagnosing SPAP are unknown. A case of SPAP diagnosed by TBLC is presented. Specimens that were useful for diagnosis were collected, and there was no adverse event following TBLC. The usefulness of TBLC for interstitial lung disease has been widely reported, but there are few reports of SPAP. We present the clinical course of TBLC in the diagnosis of SPAP.

BACKGROUND: Lysinuric protein intolerance (LPI) is a multi-organ metabolic disorder characterized by the imbalance in absorption and excretion of cationic amino acids like lysine, ornithine and arginine. Infants with LPI typically present with recurrent vomiting, poor growth, interstitial lung disease or renal impairment. The early onset of pulmonary alveolar proteinosis (PAP) has been reported to be associated with a severe form of LPI. Treatment of PAP most commonly consists of whole-lung lavage (WLL) and in autoimmune PAP, granulocyte-macrophage colony stimulating factor (GM-CSF) administration. Nevertheless, GM-CSF therapy in LPI-associated PAP has not been scientifically justified.
METHODS: We describe the case of an 8-month-old infant presenting with respiratory failure due to LPI associated with PAP, who was twice treated with WLL; firstly, while on veno-venous ECMO assistance and then by the use of a selective bronchial blocker. After the two treatments with WLL, she was weaned from daytime respiratory support while on initially subcutaneous, then on inhaled GM-CSF therapy.
CONCLUSIONS: This case supports the notion that GM-CSF therapy might be of benefit in patients with LPI-associated PAP. Further studies are needed to clarify the exact mechanism of GM-CSF in patients with LPI-associated PAP.

Pulmonary alveolar proteinosis (PAP) is a rare disease which involves the accumulation of insoluble lipoproteinaceous material in the alveoli leading to impaired gas exchange and even respiratory failure. Autoimmune PAP is the most common type and is characterized by the presence of anti-granulocyte-monocyte colony stimulating factor (anti GM-CSF) antibody. Whole lung lavage has been traditionally used as first-line management of PAP but there is a lack of clarity especially in the treatment of relapsing cases of PAP. Rituximab is an anti Cluster of Differentiate 20 (CD 20) monoclonal antibody that has been tried as salvage therapy for relapsing cases of PAP. We present a case of 35 years old female patient who was diagnosed as a case of relapsing PAP who was managed initially with neoadjuvant rituximab. This is a retrospective observational report showing novel use of neoadjuvant rituximab in a difficult case of relapsing PAP.

Background: Pulmonary alveolar proteinosis is a very rare diffuse lung disease characterized by the accumulation of amorphous and periodic acid Schiff-positive lipoproteinaceous material in the alveolar spaces due to impaired surfactant clearance by alveolar macrophages. Three main types were identified: Autoimmune, secondary and congenital. Pulmonary alveolar proteinosis has been previously reported to be associated with several systemic auto-immune diseases. Accordingly, we present the first case report of pulmonary alveolar proteinosis associated with myasthenia gravis. Case: A 27-year-old female patient, ex-smoker, developed a dyspnea on exertion in 2020. The chest X-ray detected diffuse symmetric alveolar opacities. Pulmonary infection was ruled out, particularly COVID-19 infection. The chest scan revealed the \"crazy paving\" pattern. The bronchoalveolar lavage showed a rosy liquid with granular acellular eosinophilic material Periodic acid-Schiff positive. According to the lung biopsy results, she was diagnosed with pulmonary alveolar proteinosis. The granulocyte macrophage colony-stimulating factor autoantibodies were negative. Nine months later, she was diagnosed with bulbar seronegative myasthenia gravis, confirmed with the electroneuromyography with repetitive nerve stimulation showing significant amplitude decrement of the trapezius and spinal muscles. She was treated with pyridostigmine, oral corticosteroids and azathioprine. Given the worsening respiratory condition of the patient, a bilateral whole lung lavage was performed with a partial resolution of symptoms. Thus, this previously unreported association was treated successfully with rituximab, including improvement of dyspnea, diplopia and muscle fatigability at six months of follow-up. Conclusions: This case emphasizes on the possible association of auto-immune disease to PAP, which could worsen the disease course, as the specific treatment does not exist yet. Hence, further studies are needed to establish clear-cut guidelines for PAP management, particularly when associated to auto-immune diseases.

A 67-year-old male, with a history of severe COVID-19 infection and exposure to talc was seen for worsening shortness of breath for months, requiring supplemental oxygen. He was treated for COVID-19 infection and suspected pneumonia with no improvement. His pulmonary function test (PFT) worsened and computed tomography (CT) showing bilateral airspace opacities with ground-glass opacities (GGO), also worsened over time. He underwent bronchoscopy, bronchoalveolar lavage and pathology revealed pulmonary alveolar proteinosis (PAP). He subsequently underwent whole lung lavage (WLL) which significantly improved his crazy paving pattern on CT and was successfully weaned off supplemental oxygen.

BACKGROUND: Autoimmune pulmonary alveolar proteinosis (APAP) is a diffuse lung disease that causes abnormal accumulation of lipoproteins in the alveoli; however, its pathogenesis remains unclear. Recently, APAP cases have been reported during the course of dermatomyositis. The combination of these two diseases may be coincidental; however, it may have been overlooked because differentiating APAP from a flare-up of interstitial pneumonia associated with dermatomyositis is challenging. This didactic case demonstrates the need for early APAP scrutiny.
METHODS: A 50-year-old woman was diagnosed with anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody-positive dermatitis and interstitial pneumonia in April 2021. The patient was treated with corticosteroids, tacrolimus, and cyclophosphamide pulse therapy for interstitial pneumonia complicated by MDA5 antibody-positive dermatitis, which improved the symptoms and interstitial pneumonia. Eight months after the start of treatment, a new interstitial shadow appeared that worsened. Therefore, three additional courses of cyclophosphamide pulse therapy were administered; however, the respiratory symptoms and interstitial shadows did not improve. Respiratory failure progressed, and 14 months after treatment initiation, bronchoscopy revealed turbid alveolar lavage fluid, numerous foamy macrophages, and numerous periodic acid-Schiff-positive unstructured materials. Blood test results revealed high anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody levels, leading to a diagnosis of APAP. The patient underwent whole-lung lavage, and the respiratory disturbance promptly improved. Anti-GM-CSF antibodies were measured from the cryopreserved serum samples collected at the time of diagnosis of anti-MDA5 antibody-positive dermatitis, and 10 months later, both values were significantly higher than normal.
CONCLUSIONS: This is the first report of anti-MDA5 antibody-positive dermatomyositis complicated by interstitial pneumonia with APAP, which may develop during immunosuppressive therapy and be misdiagnosed as a re-exacerbation of interstitial pneumonia. In anti-MDA5 antibody-positive dermatomyositis, APAP comorbidity may have been overlooked, and early evaluation with bronchoalveolar lavage fluid and anti-GM-CSF antibody measurements should be considered, keeping the development of APAP in mind.

BACKGROUND: Pulmonary alveolar proteinosis (PAP) and X-linked agammaglobulinemia (XLA) are rare diseases in children. Many theories infer that immunodeficiency can induce PAP, but these reports are almost all review articles, and there is little clinical evidence. We report the case of a child with both PAP and XLA.
METHODS: A 4-month-old boy sought medical treatment due to coughing and difficulty in breathing for > 2 wk. He had been hospitalized multiple times due to respiratory infections and diarrhea. Chest computed tomography and alveolar lavage fluid showed typical PAP-related manifestations. Genetic testing confirmed that the boy also had XLA. Following total lung alveolar lavage and intravenous immunoglobulin replacement therapy, the boy recovered and was discharged. During the follow-up period, the number of respiratory infections was significantly reduced, and PAP did not recur.
CONCLUSIONS: XLA can induce PAP and improving immune function contributes to the prognosis of children with this type of PAP.