The relationship between immunosuppressive therapy and clinical isolates for patients diagnosed with dermatomyositis-related interstitial lung diseases.

BACKGROUND: Immunosuppressive therapy is the main treatment for patients with interstitial lung diseases (ILD) secondary to dermatomyositis (DM). Microbial colonization or infection might be very common for these patients. However, the relationship between immunotherapy and microorganism isolates are not fully understood in these patients. OBJECTIVES: This study retrospectively analyzed on the clinical features in DM-ILD patients who had positive microbiological results during immunosuppressive therapy in our hospital. METHODS: Patients were divided into two groups, according to the result of microbiological study. Comparisons in infection-related data in various contexts were carried out. RESULTS: As a result, patients who had positive microbiological findings were manifested as higher fever degree [p = 0.01; positive group: mean ± SEM: 38.83 ± 0.15 °C, N = 28; negative group: mean ± SEM: 38.27 ± 0.15 °C; N = 28], higher serum C-reactive protein (CRP) [p less than 0.001, positive group (mean ± SEM: 31.6 ± 5.2 mg/L; N = 43); negative (mean ± SEM: 11.1 ± 1.6 mg/L; N = 86)], and lower CD3+CD4+ T cells counts than that of negative populations [p = 0.03, positive group (mean ± SEM: 0.27 ± 0.05 × 109/L; N = 31); negative group (mean ± SEM: 0.400 ± 0.03 × 109/L; N = 44)]. Longer hospital stay [p = 0.005; 21/36 vs 31/99] and higher serum FK506 concentrations [p = 0.02, positive group: 9.80 ± 1.87 ng/ml; N = 7; negative group: 5.76 ± 0.73 ng/ml; N = 27] were related to the occurrence of microorganism in the airway. Meanwhile, short-term investigation of in-hospital mortality related to airway microbial carry had no statistical difference between the both groups [p = 0.21, Log-rank (Mantel-Cox) Test]. CONCLUSIONS: Occurrence of positive isolates in DM-ILD patients may relate to higher inflammatory markers CRP, lower CD4 + T cells counts, high concentration of serum FK-506, and longer hospital stay.

Northern pig-tailed macaques ( Macaca leonina) infected with SARS-CoV-2 show rapid viral clearance and persistent immune response.

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), has become an unprecedented global health emergency. At present, SARS-CoV-2-infected nonhuman primates are considered the gold standard animal model for COVID-19 research. Here, we showed that northern pig-tailed macaques ( Macaca leonina, NPMs) supported SARS-CoV-2 replication. Furthermore, compared with rhesus macaques, NPMs showed rapid viral clearance in lung tissues, nose swabs, throat swabs, and rectal swabs, which may be due to higher expression of interferon (IFN)-α in lung tissue. However, the rapid viral clearance was not associated with good outcome. In the second week post infection, NPMs developed persistent or even more severe inflammation and body injury compared with rhesus macaques. These results suggest that viral clearance may have no relationship with COVID-19 progression and SARS-CoV-2-infected NPMs could be considered as a critically ill animal model in COVID-19 research.

Idiopathic pleuroparenchymal fibroelastosis confirmed by pathology: a case report.

The case of a patient with cough and asthma after activity that each had a 1-month duration is reported. Chest high-resolution computed tomography (HRCT) showed visceral pleural thickening in both upper lungs (especially the right lung), which was accompanied by fibrous strips and patches near the pleura, and these were accompanied by distraction bronchiectasis. Idiopathic pleuropulmonary elastosis was confirmed by thoracoscopic lung biopsy. The patient was treated with acetylcysteine, but their asthma worsened after activity and their lung function decreased significantly after 10 months. Idiopathic pleuroparenehymal fibroelastosis is a rare new type of idiopathic interstitial pneumonia, which has no effective treatment except for lung transplantation.

Activating transcription factor 3 involved in Pseudomonas aeruginosa PAO1-induced macrophage senescence.

Pseudomonas aeruginosa (PA) is one of the most prevalent pathogens that cause nosocomial infection in critical patients. Previously, we reported PA induced macrophage to senescence under the circumstance of infection. As an oxidative stress responsiveness element, activating transcription factor 3 (ATF3) might be involved in the macrophage senescence process. To test this presumption, we manipulated the expression of ATF3 in macrophage by using a PAO1 infection system. In the present study, ATF3 expression in macrophage was increased, following the duration and colony counts of PAO1 infection. Knockdown of ATF3 in macrophage resulted in increased percentage of senescent macrophage under PAO1 infection, while overexpressing ATF3 partly blocked PAO1-induced macrophage senescence. In accordance with the senescent phenotype, elevated reactive oxygen species (ROS) production was shown in ATF3 knockdown macrophages. Also, capacity of phagocytosis was also affected by manipulation of ATF3 expression in macrophages, and increased phagocytosed fluorescent beads was found in ATF3 knockdown macrophage. ATF3 might regulate the senescence process through influence on NF-κB translocation. During infection, the overexpression or downregulation of ATF3 in macrophage negatively modulated the translocation of NF-κB p65 and its phosphorylation at Ser-536. As a result, IL-6 and TNFα was elevated, while IL-10 decreased in case of ATF3 knockdown. In conclusion, ATF3 negatively regulates NF-κB translocation and activation, and participates in PA-induced macrophage senescence. As oxidative stress and inflammation induced element, ATF3 may modulate macrophage-related host defense.

Delayed severe cytokine storm and immune cell infiltration in SARS-CoV-2-infected aged Chinese rhesus macaques.

As of June 2020, Coronavirus Disease 2019 (COVID-19) has killed an estimated 440 000 people worldwide, 74% of whom were aged ≥65 years, making age the most significant risk factor for death caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To examine the effect of age on death, we established a SARS-CoV-2 infection model in Chinese rhesus macaques ( Macaca mulatta) of varied ages. Results indicated that infected young macaques manifested impaired respiratory function, active viral replication, severe lung damage, and infiltration of CD11b + and CD8 + cells in lungs at one-week post infection (wpi), but also recovered rapidly at 2 wpi. In contrast, aged macaques demonstrated delayed immune responses with a more severe cytokine storm, increased infiltration of CD11b + cells, and persistent infiltration of CD8 + cells in the lungs at 2 wpi. In addition, peripheral blood T cells from aged macaques showed greater inflammation and chemotaxis, but weaker antiviral functions than that in cells from young macaques. Thus, the delayed but more severe cytokine storm and higher immune cell infiltration may explain the poorer prognosis of older aged patients suffering SARS-CoV-2 infection.

COVID-19-like symptoms observed in Chinese tree shrews infected with SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) pandemic continues to pose a global threat to the human population. Identifying animal species susceptible to infection with the SARS-CoV-2/ HCoV-19 pathogen is essential for controlling the outbreak and for testing valid prophylactics or therapeutics based on animal model studies. Here, different aged Chinese tree shrews (adult group, 1 year old; old group, 5-6 years old), which are close relatives to primates, were infected with SARS-CoV-2. X-ray, viral shedding, laboratory, and histological analyses were performed on different days post-inoculation (dpi). Results showed that Chinese tree shrews could be infected by SARS-CoV-2. Lung infiltrates were visible in X-ray radiographs in most infected animals. Viral RNA was consistently detected in lung tissues from infected animals at 3, 5, and 7 dpi, along with alterations in related parameters from routine blood tests and serum biochemistry, including increased levels of aspartate aminotransferase (AST) and blood urea nitrogen (BUN). Histological analysis of lung tissues from animals at 3 dpi (adult group) and 7 dpi (old group) showed thickened alveolar septa and interstitial hemorrhage. Several differences were found between the two different aged groups in regard to viral shedding peak. Our results indicate that Chinese tree shrews have the potential to be used as animal models for SARS-CoV-2 infection.

Acute exacerbation of idiopathic pulmonary fibrosis: usual interstitial pneumonitis vs. possible usual interstitial pneumonitis pattern.

BACKGROUND: The prognosis of acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is very poor with a high mortality. The aim of this study was to describe the clinical features and survival of patients with AE-IPF with usual pulmonary fibrosis (UIP) and possible UIP (P-UIP) pattern on chest high resolution computed tomography (HRCT). METHODS: This retrospective study included 107 patients with AE-IPF admitted to Nanjing Drum Tower Hospital from January 2010 to December 2016. The subjects were divided into UIP (n = 86) and P-UIP group (n = 21) based on chest HRCT. Continuous variables were analyzed using Student's t test or Mann-Whitney U test. Categorical variables were analyzed using χ test. Log-rank test was used for the survival analysis. Cox proportional models evaluated the risk factors for AE occurrence and survival. RESULTS: The male, older patients, previous N-acetylcysteine use, elevated white blood cell (WBC) counts, and microbiology infection were more common in the UIP group than the P-UIP group (χ = 13.567, P < 0.001; z = -2.936, P = 0.003; χ = 5.901, P = 0.015; t = 2.048, P = 0.043; χ = 10.297, P = 0.036, respectively). The percentage of AE with UIP pattern in idiopathic interstitial pneumonia (IIP) was significantly higher than P-UIP pattern (χ = 40.011, P < 0.001). Smoking was the risk factor for AE within 6 months after IPF diagnosis in the UIP group. The cumulative proportion survival of 30-days was significantly higher in the UIP group compared with the P-UIP group (χ = 5.489, P = 0.019) despite of the similar overall survival in the two groups. Multivariate Cox regression analysis indicated WBC count, partial pressure of oxygen in artery (PaO2)/fractional concentration of inspired oxygen (FiO2), and computed tomography (CT) score were the independent predictors for survival in the UIP group (hazard ratio [HR]: 1.070, 95% confidential interval [CI]: 1.027-1.114, P = 0.001; HR: 0.992, 95% CI: 0.986-0.997, P = 0.002; and HR: 1.649, 95% CI: 1.253-2.171, P < 0.001, respectively). CONCLUSIONS: AE occurrence of UIP patients in IIP was significantly more than P-UIP cases. The short-term survival was better in the UIP group despite of the similar overall survival in the two groups. WBC count, PaO2/FiO2, and CT score were the independent predictors for survival in UIP subjects.

Clinical characteristics and outcomes of hypersensitivity pneumonitis: a population-based study in China.

BACKGROUNDS: Hypersensitivity pneumonitis (HP) is an immune-mediated interstitial lung disease (ILD) that develops in response to the inhalation of various antigens. The clinical pathologies are very complex and undetermined. The clinical features and outcomes of HP have not been fully elucidated. The aim of this study was to analyze the incidence, clinical features, and outcomes of HP patients and construct a simple clinical model for diagnosing chronic HP (CHP). METHODS: The cohort study included 101 patients with HP admitted to the Nanjing Drum Tower Hospital from January 2009 to December 2017. The patients were categorized into acute HP (AHP, n = 72) and CHP (n = 29) groups according to the updated international criteria. The clinical, imaging, treatment, and follow-up data were retrospectively reviewed. All patients were followed up until December 31, 2017. Statistical analysis was performed, and a clinical scoring system for CHP was constructed by SPSS 20.0 software. RESULTS: The incidence of HP was 2.4% in ILD inpatients in our center. Patients in the CHP group were older (t = -2.212, P = 0.029), had more smokers (χ = 8.428, P = 0.004), and longer duration of symptoms (t = -4.852, P < 0.001) than those in the AHP group. Weight loss, crackles, digital clubbing, and cyanosis were more common in the CHP group than those in the AHP group (χ = 5.862, P < 0.001; χ = 8.997, P = 0.003; χ = 11.939, P = 0.001; and χ = 4.025, P = 0.045, respectively). On chest high-resolution computed tomography (HRCT), reticular patterns, traction bronchiectasis, and accompanying honeycombing were more common in CHP cases than those in AHP cases (χ = 101.000, P < 0.001; χ = 32.048, P < 0.001; and χ = 36.568, P < 0.001, respectively). The clinical scoring system for CHP was established based on the clinical variables (age [A], duration of symptoms [D], smoking history [S], unidentified exposure [U], and chest HRCT [C]; ADSUC) (area under the curve 0.935, 95% confidence interval: 0.883-0.987, P < 0.001). Eleven patients (15.3%) in the AHP group developed CHP, and unidentified exposure was an independent risk factor for the progression of disease (P = 0.038). The survival of patients with CHP, smoking history, unidentified antigens and fibrosis on Chest HRCT were significantly worse (P = 0.011, P = 0.001, P = 0.005, and P = 0.011, respectively) by Kaplan-Meier analysis. Cox multivariate regression analysis revealed that unidentified exposure and total lung volume (TLC pred%) were independent prognostic predictors for HP patients (P = 0.017 and P = 0.017, respectively). CONCLUSIONS: The clinical features and outcomes of the CHP patients differ from those of the AHP patients. ADSUC is a simple and feasible clinical model for CHP. Unidentified exposure is an independent risk factor for the progression of AHP to CHP. Unidentified exposure and a low baseline TLC pred% are independent predictors for survival in HP patients.

Using ROS as a Second Messenger, NADPH Oxidase 2 Mediates Macrophage Senescence via Interaction with NF-κB during Pseudomonas aeruginosa Infection.

Pseudomonas aeruginosa (PA) is one of the most prevalent pathogens that cause nosocomial infection in critical patients. However, the mechanisms underlying macrophage growth status and functional changes during PA infection are yet unknown. In the present study, NADPH oxidase, gp91phox (NOX2) mediated macrophage to senescence in a PAO1 colony-dependent manner. gp91phox might regulate the senescence process through mutual interaction with the NF-κB pathway. During infection, the overexpression or downregulation of gp91phox in macrophage could affect the nuclear activity of NF-κB p65, while the downregulation of NF-κB p65 led to a suppressed expression of gp91phox. Reactive oxygen species (ROS) served as the second messenger between both molecules as the ROS inhibitor, N-acetylcysteine (NAC), could partially restore these changes. Consequently, the level of ROS and inflammatory cytokines, including IL-6 and TNFα, elevated during PAO1 infection, and their production altered as a result of the genetic manipulation of gp91phox and NF-κB p65, as well as NAC treatment. Also, the senescent phenotypes, SA-ß-gal staining and p16ink4a, changed after genetic manipulation with gp91phox and NF-κB p65 and NAC treatment. The capacity of phagocytosis in macrophages was decreased during senescence. In conclusion, PA directs the macrophage towards senescence, and senescent macrophages exhibit a decreased ability of phagocytosis. This process of senescence was regulated by the interactions between NADPH oxidase gp91phox and NF-κB p65 via ROS as a second messenger.

Pseudomonas aeruginosa induces cellular senescence in lung tissue at the early stage of two-hit septic mice.

We presume that severe secondary Pseudomonas aeruginosa (PA) infection can lead to cellular senescence in lung tissue and thus contribute to high mortality. We established a two-hit mouse model using cecal ligation and puncture (CLP) followed by sublethal PA lung infection. In lung tissue, increased infiltration of inflammatory cells, elevated lung injury and augmented cellular senescence was shown in mice with CLP followed by sublethal PA infection, and these observations reached a higher rank when higher (H) loads PA (PAO1) were administered to CLP mice (CLP + PAO1-H). Accordingly, oxidative stress-related element gp91phox and inflammation regulator NF-κB were greatly activated in CLP + PAO1-H mice compared to others. There was no obvious inflammation or cellular senescence in sham control, PAO1-infected mice. Consequently, CLP + PAO1-H mice had the highest expression levels of inflammatory cytokines IL-6, TNFα and iNOS among those groups. There was lower bacterial clearance ability in CLP + PAO1-H mice than in other mice. CLP + PAO1-H only had approximately 10% survival after 7 days of investigation and was much lower than others. In conclusion, higher mortality due to increased lung inflammation and cellular senescence are observed in mice with increased loads of PA infection secondary to CLP.

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.

Serum Krebs von den Lungen-6 level as a diagnostic biomarker for interstitial lung disease in Chinese patients.

OBJECTIVES: The purpose of this study was to determine the diagnostic and prognostic values of serum KL-6 levels in Chinese patients with interstitial lung disease (ILDs). METHODS: A total of 1084 subjects including 373 cases of ILDs, 584 cases of non-ILD pulmonary diseases, and 127 healthy individuals were recruited from three clinical centers in China between January 2011 and December 2013. A total of 106 patients undergoing treatments for ILDs in Shanghai Pulmonary Hospital between January 2011 and December 2013 were enrolled. Baseline and posttreatment serum KL-6 levels were determined. RESULTS: Serum KL-6 levels in patients with ILDs were significantly higher than those in patients with non-ILD pulmonary diseases or in healthy individuals (1492.09 ± 2230.08 U/mL vs 258.67 ± 268.73 U/mL or 178.73 ± 71.17 U/mL, all P < 0.05). At the cut-off value of 500 U/mL, the sensitivity and specificity of serum KL-6 as a diagnostic marker for ILDs was 77.75% and 94.51%, respectively. The Kappa value was 0.743 (P < 0.001). The area below the receiver operating characteristic curve was 0.922 with a 95% Confidence interval of 0.904-0.941 (P < 0.001). The posttreatment serum KL-6 levels significantly reduced in patients with improved ILDs, whereas markedly increased in patients with exacerbated ILDs (All P < 0.05). CONCLUSIONS: Serum KL-6 levels might be a promising diagnostic biomarker for ILDs in Chinese patients. The prognostic value of serum KL-6 levels for ILDs remains to be verified by large-scaled studies.

Prognostic Value of MAC30 Expression in Human Pure Squamous Cell Carcinomas of the Lung.

Recent evidence haas indicated that meningioma-associate protein (MAC30) exhibits different expression patterns in various tumors. However, little is known about the value of MAC30 in human squamous cell carcinoma of lung (SQCLC). The purpose of our study was to investigate the expression of MAC30 and to explore its clinical significance in SQCLC patients. A total of 156 Chinese patients diagnosed with SQCLC were selected for this study. The expression of MAC30 in all tissues was confirmed by immunohistochemical staining. Quantitative real-time PCR was performed to analyze MAC30 mRNA expression in 32 cases of SQCLC patients with corresponding non-tumor lung tissues. We observed enhanced mRNA expression of MAC30 in SQCLC as compared to control samples. Further, elevated MAC30 protein expression was strongly associated with poor tumor differentiation, TNM stage, and lymph node metastasis. In addition, we observed that patients with increased MAC30 expression demonstrated poor overall survival. Multivariate analysis explicated that increased MAC30 expression was a valuable independent predictable factor for poor tumor differentiation and short survival in SQCLC patients. Our present study suggests that MAC30 may serve as a biomarker for poor tumor differentiation and outcomes of patients with SQCLC.

Bile acids induce activation of alveolar epithelial cells and lung fibroblasts through farnesoid X receptor-dependent and independent pathways.

BACKGROUND AND OBJECTIVE: The roles of bile acid microaspiration and bile acid-activated farnesoid X receptor (FXR) in the pathogenesis of idiopathic pulmonary fibrosis (IPF) remain unclear. We hypothesized that bile acids activate alveolar epithelial cells (AECs) and lung fibroblasts, which may be regulated by FXR activation. METHODS: Human AECs and normal or IPF-derived lung fibroblast cells were incubated with the three major bile acids: lithocholic acid (LCA), deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA). The AECs injury indices, epithelial-mesenchymal transition (EMT) and lung fibroblast activation were evaluated. FXR expression in IPF lungs and the roles of FXR and FXR-independent pathways in bile acid-induced profibrotic effects were also investigated. RESULTS: LCA, DCA and CDCA reduced cell viability and increased intracellular reactive oxygen species (ROS) production in A549 cells. They all induced EMT, as shown by enhanced α-SMA and vimentin and decreased E-cadherin levels. LCA directly induced differentiation of lung fibroblasts to myofibroblasts. All three bile acids promoted cellular migration but not proliferation of lung fibroblasts. FXR expression was upregulated in IPF lungs, and inhibition of FXR restrained the bile acid-induced EMT and lung fibroblast activation. Differentiation and proliferation were enhanced in lung fibroblasts exposed to conditioned medium from bile acid-stimulated A549 cells, which contained increased levels of profibrotic factors. TGF-ß/Smad3 signaling was also involved in the bile acid-induced EMT and lung fibroblast differentiation. CONCLUSION: Bile acid microaspiration may promote the development of pulmonary fibrosis by inducing activation of AECs and lung fibroblasts via FXR-dependent and independent pathways.

Clinical and Radiological Profile of Acute Fibrinous and Organizing Pneumonia: A Retrospective Study.

BACKGROUND: Acute fibrinous and organizing pneumonia (AFOP) is a unique pathological entity with intra-alveolar fibrin in the form of "fibrin balls" and organizing pneumonia. It was divided into rare idiopathic interstitial pneumonia according to the classification notified by American Thoracic Society/European Respiratory Society in 2013. As a rare pathological entity, it is still not well known and recognized by clinicians. We reviewed the clinical features of 20 patients with AFOP diagnosed in a teaching hospital. METHODS: The medical records of 20 patients with biopsy-proven diagnosis of AFOP were retrospectively reviewed. The patients' symptoms, duration of the disease, comorbidities, clinical laboratory data, pulmonary function testing, radiographic studies, and the response to treatment were extracted and analyzed. RESULTS: Fever was the most common symptom and was manifested in 90% of AFOP patients. For clinical laboratory findings, systematic inflammatory indicators, including C-reactive protein and erythrocyte sedimentation rate, were significantly higher than normal in AFOP patients. In accordance with this increased indicators, injured liver functions were common in AFOP patients. Inversely, AFOP patients had worse clinical conditions including anemia and hypoalbuminemia. For pulmonary function testing, AFOP patients showed the pattern of restrictive mixed with obstructive ventilation dysfunction. For high-resolution computerized tomography (HRCT) findings, the most common pattern for AFOP patients was lobar consolidation which was very similar to pneumonia. However, unlike pneumonia, AFOP patients responded well to glucocorticoids. CONCLUSION: Patients with AFOP manifest as acute inflammatory-like clinical laboratory parameters and lobar consolidation on HRCT, but respond well to steroid.

Occupational inhalational exposure and serum GM-CSF autoantibody in pulmonary alveolar proteinosis.

OBJECTIVES: Although the serum granulocyte-macrophage colony stimulating factor autoantibody (GMAb) levels have been recognised as a diagnostic marker in primary pulmonary alveolar proteinosis (PAP), their role in PAP with occupational inhalational exposure (PAPo) remains unclear. METHODS: Forty-five consecutive patients with PAP were enrolled. Each patient with PAP was assessed for baseline clinical characteristics, chest high-resolution CT (HRCT), serum GMAb and occupational exposure. Fifty healthy controls were included to define normal ranges for GMAb levels. Ninety-seven hospital controls with other respiratory diseases were included to establish prevalence of a history of occupational inhalation exposure. RESULTS: According to the serum GMAb cut-off value of 2.39 µg/mL, 84.4% of the recruited patients with PAP had positive serum GMAb with a median level of 28.7 µg/mL, defined as autoimmune PAP, and the remaining 15.6% had negative serum GMAb with a median level of 0.16 µg/mL, defined as non-autoimmune PAP. Also, 34.2% of patients with autoimmune PAP had a history of occupational inhalational exposure, which was not significantly higher than that of hospital controls (34.2% vs 19.6%, p=0.072). Four patients with PAPo showed negative GMAb. Their arterial oxygen tension, pulmonary function parameters and chest HRCT features were significantly different when compared with patients with autoimmune PAP (p<0.05). These four non-autoimmune occupational lung disease cases culminated in 3 deaths and a lung transplant. CONCLUSIONS: A number of patients with PAP who may have occupational inhalational exposure and negative serum GMAb represent a high possibility of silicoproteinosis and very poor survival.