Project description:BACKGROUND: Pulmonary alveolar proteinosis (PAP) is a rare disease characterised by accumulation of lipoproteinaceous material within alveoli, occurring in three clinically distinct forms: congenital, acquired and secondary. Among the latter, lysinuric protein intolerance (LPI) is a rare genetic disorder caused by defective transport of cationic amino acids. Whole Lung Lavage (WLL) is currently the gold standard therapy for severe cases of PAP. CASE PRESENTATION: We describe the case of an Italian boy affected by LPI who, by the age of 10, developed digital clubbing and, by the age of 16, a mild restrictive functional impairment associated with a high-resolution computed tomography (HRCT) pattern consistent with pulmonary alveolar proteinosis. After careful assessment, he underwent WLL. CONCLUSION: Two years after WLL, the patient has no clinical, radiological or functional evidence of pulmonary disease recurrence, thus suggesting that WLL may be helpful in the treatment of PAP secondary to LPI.
Project description:Implications In this commentary, we describe the evidence-based approach used to identify the primary cause of EVALI and to curb the 2019 outbreak. We also discuss future research opportunities and public health practice considerations to prevent a resurgence of EVALI.
Project description:Pulmonary alveolar proteinosis (PAP) comprises a heterogenous group of diseases characterized by abnormal surfactant accumulation resulting in respiratory insufficiency, and defects in alveolar macrophage- and neutrophil-mediated host defense. Basic, clinical and translational research over the past two decades have raised PAP from obscurity, identifying the molecular pathogenesis in over 90% of cases as a spectrum of diseases involving the disruption of GM-CSF signaling. Autoimmune PAP represents the vast majority of cases and is caused by neutralizing GM-CSF autoantibodies. Genetic mutations that disrupt GM-CSF receptor signaling comprise a rare form of hereditary PAP. In both autoimmune and hereditary PAP, loss of GM-CSF signaling blocks the terminal differentiation of alveolar macrophages in the lungs impairing the ability of alveolar macrophages to catabolize surfactant and to perform many host defense functions. Secondary PAP occurs in a variety of clinical diseases that presumedly cause the syndrome by reducing the numbers or functions of alveolar macrophages, thereby impairing alveolar macrophage-mediated pulmonary surfactant clearance. A similar phenotype occurs in mice deficient in the production of GM-CSF or GM-CSF receptors. PAP and related research has uncovered a critical and emerging role for GM-CSF in the regulation of pulmonary surfactant homeostasis, lung host defense, and systemic immunity.
Project description:Inhalation of aerosolized products generated by different electronic devices is called vaping. E-cigarettes or Vaping product use Associated Lung Injury (EVALI) outbreak peaked in August-September 2019 and gradually declined. EVALI remains a diagnosis of exclusion which presents as an acute lung injury in the vaping population. Vitamin E acetate and its products are implicated as one of the cytotoxic agents causing airway centered pneumonitis. Lipid laden macrophages are found in samples of BAL fluid but their role in cytopathology of the disease remains unclear. We present a 57 years old man who came to the emergency department at Monmouth Medical Center, New Jersey in fall, 2019. Reportedly he has been vaping THC about 100g every day for past three days. At initial presentation, he had fever, shortness of breath and hypoxia requiring supplemental oxygen. He was empirically treated with levofloxacin 500 mg for five days without a significant improvement in his symptoms. Non-contrast chest CT scan showed bilateral ground-glass opacities, indicative of diffuse alveolar damage. He underwent flexible bronchoscopy to rule out infective pneumonia followed by auto-immune work-up that was non-conclusive. He was given 1 mg/kg methylprednisolone with a quick taper of oral steroids leading to the resolution of symptoms. At six months follow-up, imaging showed near resolution of ground-glass opacities.
Project description:BackgroundE-cigarette or vaping has become an increasingly popular alternative to smoking tobacco. In September 2019 multiple cases of confirmed E-cigarette or vaping product use associated lung injury were published. However, there is limited knowledge regarding the pathologic mechanism of this condition.MethodsWe performed a systematic literature review in PubMed and EMBASE aiming to obtain additional clinical data on confirmed E-cigarette or vaping product use associated lung injury cases with lung biopsy results. With this information we hope to determine whether this condition is related to a histopathological pattern of acute lung injury instead of lipid deposits.ResultsSeven articles were reviewed and a total of 27 cases were included. Imaging findings predominantly showed presence of diffuse bilateral ground glass opacities. A majority of patients had complete resolution of the disease. The most common histopathological pattern was organizing pneumonia present in almost half of the patients. Other frequently occurring patterns included diffuse alveolar damage and acute fibrinous pneumonitis; lipoid pneumonia was found in one case.ConclusionThe underlying pathophysiological mechanism in E-cigarette or vaping product use associated lung injury is most likely acute lung injury related to direct inhalant-mediated parenchymal inflammation.
Project description:Pulmonary Alveolar Proteinosis (PAP) patients exhibit an acquired deficiency of biologically active granulocyte-macrophage colony stimulating factor (GM-CSF) attributable to GM-CSF specific autoantibodies. PAP alveolar macrophages are foamy, lipid-filled cells with impaired surfactant clearance and markedly reduced expression of the transcription factor peroxisome proliferator-activated receptor gamma (PPAR?) and the PPAR?-regulated ATP binding cassette (ABC) lipid transporter, ABCG1. An open label proof of concept Phase II clinical trial was conducted in PAP patients using rituximab, a chimeric murine-human monoclonal antibody directed against B lymphocyte specific antigen CD20. Rituximab treatment decreased anti-GM-CSF antibody levels in bronchoalveolar lavage (BAL) fluid, and 7/9 patients completing the trial demonstrated clinical improvement as measured by arterial blood oxygenation.This study sought to determine whether rituximab therapy would restore lipid metabolism in PAP alveolar macrophages.BAL samples were collected from patients pre- and 6-months post-rituximab infusion for evaluation of mRNA and lipid changes.Mean PPAR? and ABCG1 mRNA expression increased 2.8 and 5.3-fold respectively (p???0.05) after treatment. Lysosomal phospholipase A2 (LPLA2) (a key enzyme in surfactant degradation) mRNA expression was severely deficient in PAP patients pre-treatment but increased 2.8-fold post-treatment. In supplemental animal studies, LPLA2 deficiency was verified in GM-CSF KO mice but was not present in macrophage-specific PPAR? KO mice compared to wild-type controls. Oil Red O intensity of PAP alveolar macrophages decreased after treatment, indicating reduced intracellular lipid while extracellular free cholesterol increased in BAL fluid. Furthermore, total protein and Surfactant protein A were significantly decreased in the BAL fluid post therapy.Reduction in GM-CSF autoantibodies by rituximab therapy improves alveolar macrophage lipid metabolism by increasing lipid transport and surfactant catabolism. Mechanisms may involve GM-CSF stimulation of alveolar macrophage ABCG1 and LPLA2 activities by distinct pathways.
Project description:This case report demonstrates 44-year old man, presenting with recurring clinical pneumonias during a period of over 1 year. The patient was clinically affected with, i.a., weight loss, finger clubbing and severely reduced diffusion capacity. Repetitive chest x-rays showed bilateral and consolidating infiltrates, and a high-resolution computed tomography of the thorax (HRCT) exposed ground glass opacities superimposed on a reticular pattern as the so-called 'crazy paving' pattern. A bronchoscopic alveolar lavage revealed alveolar proteinaceous material compatible with the diagnosis pulmonary alveolar proteinosis (PAP). PAP is a rare syndrome where surfactant is accumulated in the alveoli, causing respiratory disease in typically young to middle-aged patients with male predominance. Both symptoms and prognosis are variable, and range from spontaneous remission to terminal respiratory failure. The standard treatment is whole lung lavage, where surfactant is mechanically rinsed from the lungs. The lack of specific clinical symptoms makes it easy to overlook the diagnosis, as supported by this case report. It serves as a reminder, that the findings of a crazy paving pattern on HRCT in young adults should alert of this rare disease, and advises on the further examinations required to make the diagnosis.
Project description:Primary pulmonary alveolar proteinosis (PAP) is a rare syndrome characterized by accumulation of surfactant in the lungs that is presumed to be mediated by disruption of granulocyte/macrophage colony-stimulating factor (GM-CSF) signaling based on studies in genetically modified mice. The effects of GM-CSF are mediated by heterologous receptors composed of GM-CSF binding (GM-CSF-Ralpha) and nonbinding affinity-enhancing (GM-CSF-Rbeta) subunits. We describe PAP, failure to thrive, and increased GM-CSF levels in two sisters aged 6 and 8 yr with abnormalities of both GM-CSF-Ralpha-encoding alleles (CSF2RA). One was a 1.6-Mb deletion in the pseudoautosomal region of one maternal X chromosome encompassing CSF2RA. The other, a point mutation in the paternal X chromosome allele encoding a G174R substitution, altered an N-linked glycosylation site within the cytokine binding domain and glycosylation of GM-CSF-Ralpha, severely reducing GM-CSF binding, receptor signaling, and GM-CSF-dependent functions in primary myeloid cells. Transfection of cloned cDNAs faithfully reproduced the signaling defect at physiological GM-CSF concentrations. Interestingly, at high GM-CSF concentrations similar to those observed in the index patient, signaling was partially rescued, thereby providing a molecular explanation for the slow progression of disease in these children. These results establish that GM-CSF signaling is critical for surfactant homeostasis in humans and demonstrate that mutations in CSF2RA cause familial PAP.
Project description:Pulmonary alveolar proteinosis (PAP) is a devastating lung disease caused by abnormal surfactant homeostasis, with a prevalence of 6-7 cases per million population worldwide. While mutations causing hereditary PAP have been reported, the genetic basis contributing to autoimmune PAP (aPAP) has not been thoroughly investigated. Here, we conducted a genome-wide association study of aPAP in 198 patients and 395 control participants of Japanese ancestry. The common genetic variant, rs138024423 at 6p21, in the major-histocompatibility-complex (MHC) region was significantly associated with disease risk (Odds ratio [OR]?=?5.2; P?=?2.4?×?10-12). HLA fine-mapping revealed that the common HLA class II allele, HLA-DRB1*08:03, strongly drove this signal (OR?=?4.8; P?=?4.8?×?10-12), followed by an additional independent risk allele at HLA-DP?1 amino acid position 8 (OR?=?0.28; P?=?3.4?×?10-7). HLA-DRB1*08:03 was also associated with an increased level of anti-GM-CSF antibody, a key driver of the disease (??=?0.32; P?=?0.035). Our study demonstrated a heritable component of aPAP, suggesting an underlying genetic predisposition toward an abnormal antibody production.