Autoimmune Pulmonary Alveolar Proteinosis with Suspected Exacerbation after Osimertinib Administration for Lung Cancer.

A 46-year-old woman with lung cancer who received chemotherapy was admitted to our hospital for lower-lobe bilateral ground-glass opacity (GGO). GGO developed after the lung cancer diagnosis, deteriorated after the initiation of osimertinib, and incompletely decreased after interrupting osimertinib; therefore, flexible bronchoscopy was performed. Transbronchial lung biopsy histology and anti-granulocyte/macrophage colony-stimulating factor autoantibody positivity revealed autoimmune pulmonary alveolar proteinosis (aPAP) that did not require treatment. This rare case of aPAP comorbid with lung cancer suggested that using PAP findings to differentiate from drug-induced lung injury or lymphangitis is difficult and that osimertinib was suspected to exacerbate aPAP.

Pulmonary effects of exposure to indium and its compounds: cross-sectional survey of exposed workers and experimental findings in rodents.

BACKGROUND: Many studies have shown that occupational exposure to indium and its compounds could induce lung disease. Although animal toxicological studies and human epidemiological studies suggest indium exposure may cause lung injury, inflammation, pulmonary fibrosis, emphysema, pulmonary alveolar proteinosis, and even lung cancer, related data collected from humans is currently limited and confined to single workplaces, and the early effects of exposure on the lungs are not well understood. OBJECTIVES: This study combined population studies and animal experiments to examine the links of indium with pulmonary injury, as well as its mechanism of action. A cross-sectional epidemiological study of indium-exposed workers from China was conducted to evaluate associations between occupational indium exposure and serum biomarkers of early effect. This study also compares and analyzes the causal perspectives of changes in human serum biomarkers induced by indium compound exposure and indium exposure-related rat lung pathobiology, and discusses possible avenues for their recognition and prevention. METHODS: This is a study of 57 exposed (at least 6 h per day for one year) workers from an indium ingot production plant, and 63 controls. Indium concentration in serum, urine, and airborne as exposure indices were measured by inductively coupled plasma-mass spectrometry. Sixteen serum biomarkers of pulmonary injury, inflammation, and oxidative stress were measured using ELISA. The associations between serum indium and 16 serum biomarkers were analyzed to explore the mechanism of action of indium on pulmonary injury in indium-exposed workers. Animal experiments were conducted to measure inflammatory factors levels in bronchoalveolar lavage fluid (BALF) and lung tissue protein expressions in rats. Four different forms of indium compound-exposed rat models were established (intratracheal instillation twice per week, 8 week exposure, 8 week recovery). Model I: 0, 1.2, 3, and 6 mg/kg bw indium tin oxide group; Model II: 0, 1.2, 3, and 6 mg/kg bw indium oxide (In2O3) group; Model III: 0, 0.523, 1.046, and 2.614 mg/kg bw indium sulfate (In2(SO4)3) group; Model IV: 0, 0.065, 0.65, and 1.3 mg/kg bw indium trichloride (InCl3) group. Lung pathological changes were assessed by hematoxylin & eosin, periodic acid Schiff, and Masson's staining, transmission electron microscopy, and the protein changes were determined by immunohistochemistry. RESULTS: In the production workshop, the airborne indium concentration was 78.4 µg/m3. The levels of serum indium and urine indium in indium-exposed workers were 39.3 µg/L and 11.0 ng/g creatinine. Increased lung damage markers, oxidative stress markers, and inflammation markers were found in indium-exposed workers. Serum indium levels were statistically and positively associated with the serum levels of SP-A, IL-1ß, IL-6 in indium-exposed workers. Among them, SP-A showed a duration-response pattern. The results of animal experiments showed that, with an increase in dosage, indium exposure significantly increased the levels of serum indium and lung indium, as well as the BALF levels of IL­1ß, IL­6, IL­10, and TNF­α and up-regulated the protein expression of SP-A, SP-D, KL-6, GM-CSF, NF-κB p65, and HO-1 in all rat models groups. TEM revealed that In2(SO4)3 and InCl3 are soluble and that no particles were found in lung tissue, in contrast to the non-soluble compounds (ITO and In2O3). No PAS-staining positive substance was found in the lung tissue of In2(SO4)3 and InCl3 exposure groups, whereas ITO and In2O3 rat models supported findings of pulmonary alveolar proteinosis and interstitial fibrosis seen in human indium lung disease. ITO and InCl3 can accelerate interstitial fibrosis. Findings from our in vivo studies demonstrated that intra-alveolar accumulation of surfactant (immunohistochemistry) and characteristic cholesterol clefts granulomas of indium lung disease (PAS staining) were triggered by a specific form of indium (ITO and In2O3). CONCLUSIONS: In indium-exposed workers, biomarker findings indicated lung damage, oxidative stress and an inflammatory response. In rat models of the four forms of indium encountered in a workplace, the biomarkers response to all compounds overall corresponded to that in humans. In addition, pulmonary alveolar proteinosis was found following exposure to indium tin oxide and indium oxide in the rat models, and interstitial fibrosis was found following exposure to indium tin oxide and indium trichloride, supporting previous report of human disease. Serum SP-A levels were positively associated with indium exposure and may be considered a potential biomarker of exposure and effect in exposed workers.

N-acetylcysteine alleviates pulmonary alveolar proteinosis induced by indium-tin oxide nanoparticles in male rats: involvement of the NF-κB signaling pathway.

Indium-tin oxide (ITO) was previously found to have a toxic effect on lung tissues, and oxidative stress and the inflammatory response are two important mechanisms of ITO­induced lung injury. N-acetylcysteine (NAC) has been found to exhibit antioxidant and anti­inflammatory properties. The current study aimed to evaluate the possible protective effects of NAC against ITO nanoparticle (Nano-ITO)-induced pulmonary alveolar proteinosis (PAP) in adult male Sprague-Dawley rats, especially via modulation of nuclear factor-kappa B (NF-κB) signaling. For this purpose, 50 rats were randomly allocated into five groups (10 rats each) as follows: (1) control group; (2) saline group; (3) NAC (200 mg/kg) group; (4) PAP model group receiving a repeated intratracheal dose of Nano-ITO (6 mg/kg); and (5) PAP model+NF-κB inhibitor (NAC) group pre-treated intraperitoneally with NAC (200 mg/kg) twice per week before the administration of an intratracheal dose of Nano-ITO (6 mg/kg). Rats were then euthanized under anesthesia, and their lungs were removed for histopathological and biochemical investigations. A 6 mg/kg dose of Nano-ITO markedly altered the levels of some oxidative stress biomarkers. The histological examination of Nano-ITO-exposed rats demonstrated diffused alveolar damage that involved PAP, cholesterol crystals, alveolar fibrosis, pulmonary fibrosis, and alveolar emphysema. The immunohistochemical results of Nano-ITO-exposed rats revealed strongly positive NF-κB p65 and inhibitory kappa B kinase (IKK)-ß and weakly positive inhibitor of kappa-B subunit alpha (IκB-α) staining reactivity in the nuclei of cells lining the epithelium of the bronchioles and alveoli. Moreover, Nano-ITO activated the NF-κB pathway. However, pre-treatment with NAC significantly attenuated Nano-ITO-evoked alterations in the previously mentioned parameters, highlighting their antioxidant, anti-inflammatory, and anti-apoptotic potential. The results indicated that the degree of pulmonary fibrosis and proteinosis in the NAC­treated group was improved compared with that in the Nano-ITO-induced PAP model group. The level of malondialdehyde was also decreased overall in the NAC-treated group compared with that in the Nano-ITO-induced model group, indicating that the pulmonary fibrosis degree and oxidation levels were decreased. The present study also demonstrated that NAC increased the activity of antioxidant enzyme superoxide dismutase and total antioxidant capacity, indicating that it could alleviate oxidative stress in the lung tissue of Nano-ITO­exposed rats. In addition, NAC reduced the production of pro­inflammatory cytokines interleukin (IL)­1ß, IL­6, and tumor necrosis factor (TNF)­α, and increased the levels of anti­inflammatory factor IL­10. The current study demonstrated that NAC can effectively attenuate Nano-ITO­induced lung injury by reducing oxidative damage and the inflammatory response.

Pulmonary and Systemic Toxicity in a Rat Model of Pulmonary Alveolar Proteinosis Induced by Indium-Tin Oxide Nanoparticles.

PURPOSE: The main objective of this study was to clarify the biodistribution and in vivo toxicological effects of indium-tin oxide nanoparticles (Nano-ITO) in male rats. METHODS: Dose-response (three divided doses) and time-course studies (six exposure durations) were performed to examine Nano­ITO-induced pulmonary and systemic toxicity. At the end of the experiment, hematology and serum biochemical parameters were determined, and cytokines levels and oxidative stress were analyzed in the bronchoalveolar lavage fluid. In addition, indium biodistribution following Nano­ITO exposure was determined using inductively coupled plasma mass spectrometer to measure indium concentration in the lung, spleen, brain, liver, kidney, and testis. Rat lung tissues were also harvested for staining with hematoxylin and eosin, periodic acid Schiff stain, Masson's trichrome, and Sirius red. RESULTS: Relative lung weights were significantly increased in all Nano-ITO-exposed groups. All organs exhibited a statistically significant difference in indium levels. Rat exposure to Nano­ITO resulted in a dose-response increase in acute systemic inflammation and injury. BALF analysis revealed significantly elevated levels of lung oxidative stress, pulmonary injury, and inflammatory markers across most groups. Serum biochemistry results showed that Nano-ITO could affect the liver and renal functions of rats when exposed for 3 days. Compared with the control group, significant inflammatory responses or pathological changes were observed in the liver, kidney, and testis of rats at different sampling times and three doses examined. Histopathologically, foci of slight-to-severe pulmonary inflammatory response along with acute inflammatory, pulmonary fibrosis and alveolar proteinosis were detected, and the severity of these lesions worsened in a dose- and time-dependent manner. DISCUSSION: These findings provide novel evidence that enhanced progressive massive pulmonary fibrosis, diffuse interstitial fibrosis, and collagen accumulation play a role in the development of pulmonary alveolar proteinosis following Nano-ITO exposure.

Sirolimus-Induced Pulmonary Alveolar Proteinosis in the Context of Hematopoietic Stem Cells Transplant Rejection: A Case Report.

Pulmonary alveolar proteinosis (PAP) is a rare parenchymal pulmonary disease, characterized by the accumulation of surfactant material in alveoli. Rare cases of pulmonary alveolar proteinosis have been reported following the use of sirolimus. All published cases have been described following solid organ transplantation, and symptoms improved quickly after treatment's cessation. We describe a case of PAP secondary to sirolimus treating graft-versus-host reaction in a patient who received a stem cell transplant for chronic lymphocytic leukemia. Pulmonary alveolar proteinosis was cured after stopping sirolimus without any other therapeutic management. PAP can be a rare but serious side effect of sirolimus. It is important to rule out other causes of primary or secondary PAP before suggesting a toxic drug cause. The main challenge is to quickly diagnose this side effect to stop exposure to the toxic agent.

[Mechanism of nano-indium-tin oxide inducing pulmonary alveolar proteinosis in Sprague-Dawley rats].

Objective: To investigate the pathogenesis of pulmonary alveolar proteinosis in rats induced by nano-indium-tin oxide exposure, and to provide a basis for further determining the limit of occupational exposure to indium and developing related protection measures. Methods: In August 2018, a total of 40 specific pathogen-free Sprague-Dawley rats, with an age of 6-8 weeks and a body weight of (200±10) g, were randomly divided into control group, low-dose group (1.2 mg/kg) , middle-dose group (3 mg/kg) , and high-dose group (6 mg/kg) , with 10 rats in each group. After 1 week of routine feeding, the rats were given non-exposed intratracheal instillation twice every week, with an interval of 3 days, for 12 consecutive weeks. Body weight was measured every week during exposure to observe the change in body weight; The rats were anesthetized and sacrificed by chloral hydrate after the exposure ended, and lung tissue and serum were collected; Hematoxylin-eosin staining and periodic acid-Schiff (PAS) staining were performed for lung tissue to observe pathological results; Inductively coupled plasma mass spectrometry was used to measure the serum level of indium; ELISA was used to measure the levels of surfactant protein A (SP-A) , surfactant protein D (SP-D) , and the type II alveolar cell surface antigen Krebs von den Lungen-6 (KL-6) in lung tissue and the serum level of granulocyte-macrophage colony-stimulating factor (GM-CSF) . Results: The pathological results showed that the rats in the control group had basically complete alveolar structure, and after intratracheal instillation of nano indium-tin oxide, uniform, eosinophilic, and unstructured granular substances were observed in the alveolar space of the low-, middle-, and high-dose exposure groups, with macrophage proliferation and an increase in macrophages, especially in the high-dose group. Negative PAS staining was observed in the control group, while substances with positive PAS staining were observed in lung tissue in each exposure group. The three exposure groups had a significantly higher serum level of indium than the control group (P<0.05) . Compared with the control group, the three exposure groups had significant increases in SP-A, SP-D, and KL-6 in lung tissue and a significant reduction in GM-CSF in serum (P<0.05) . Conclusion: Pulmonary alveolar proteinosis in rats may be associated with the destruction of alveolar macrophages caused by nano-indium-tin oxide and the aggregation of pulmonary surfactants due to disorders in the metabolism and clearance of pulmonary surfactants by macrophages.

Indium oxide nanoparticles induce lung intercellular toxicity between bronchial epithelial cells and macrophages.

Concerns have been raised over the safety and health of industrial workers exposed to indium oxide nanoparticles (IO-NPs) when working. IO-NPs were previously shown in vitro and in vivo to be cytotoxic, but the mechanism of pathogenesis was unclear. In this study, the effects of IO-NPs on lung cells associated with respiratory and immune barriers and the toxic effects of intercellular cascades were studied. Here IO-NPs had acute toxicity to Wistar rats over a time course (5 days post-intratracheal instillation). Following treatment epithelial cells (16HBE) or macrophages (RAW264.7) with IO-NPs or IO fine particles (IO-FPs), the damage of 16HBE cells caused by IO-NPs was serious, mainly in the mitochondrial and rough endoplasmic reticulum. The lactate dehydrogenase level also showed that cytotoxicity in vitro was more serious for IO-NPs compared with IO-FPs. The level of In3+ (examined by inductively coupled plasma mass spectrometry) in 16HBE cells was 10 times higher than that in RAW cells. In3+ , releasing from IO-NPs absorbed by 16HBE cells, could not only significantly inhibit the phagocytosis and migration of macrophages (P < .0001), but also stimulate RAW cells to secrete high levels of inflammatory cytokines. IO-NPs can directly damage pulmonary epithelial cells. The In3+ released by epithelial cells affect the phagocytosis and migration of macrophages, which may be a new point for the decrease in the clearance of alveolar surfactants and the development of IO-related pulmonary alveolar proteinosis.

Effects of physicochemical properties of TiO2 nanomaterials for pulmonary inflammation, acute phase response and alveolar proteinosis in intratracheally exposed mice.

Nanomaterial (NM) characteristics may affect the pulmonary toxicity and inflammatory response, including specific surface area, size, shape, crystal phase or other surface characteristics. Grouping of TiO2 in hazard assessment might be challenging because of variation in physicochemical properties. We exposed C57BL/6 J mice to a single dose of four anatase TiO2 NMs with various sizes and shapes by intratracheal instillation and assessed the pulmonary toxicity 1, 3, 28, 90 or 180 days post-exposure. The quartz DQ12 was included as benchmark particle. Pulmonary responses were evaluated by histopathology, electron microscopy, bronchoalveolar lavage (BAL) fluid cell composition and acute phase response. Genotoxicity was evaluated by DNA strand break levels in BAL cells, lung and liver in the comet assay. Multiple regression analyses were applied to identify specific TiO2 NMs properties important for the pulmonary inflammation and acute phase response. The TiO2 NMs induced similar inflammatory responses when surface area was used as dose metrics, although inflammatory and acute phase response was greatest and more persistent for the TiO2 tube. Similar histopathological changes were observed for the TiO2 tube and DQ12 including pulmonary alveolar proteinosis indicating profound effects related to the tube shape. Comparison with previously published data on rutile TiO2 NMs indicated that rutile TiO2 NMs were more inflammogenic in terms of neutrophil influx than anatase TiO2 NMs when normalized to total deposited surface area. Overall, the results suggest that specific surface area, crystal phase and shape of TiO2 NMs are important predictors for the observed pulmonary effects of TiO2 NMs.

The early onset and persistent worsening pulmonary alveolar proteinosis in rats by indium oxide nanoparticles.

Workplace inhalation exposure to indium compounds has been reported to produce 'indium lung disease' characterized by pulmonary alveolar proteinosis (PAP), granulomas, and pulmonary fibrosis. However, there is little information about the pulmonary toxicity of nano-sized indium oxide (In2O3), which is widely used in various applications such as liquid crystal displays. In this study, we evaluated the time-course and dose-dependent lung injuries by In2O3 nanoparticles (NPs) after a single intratracheal instillation to rats. In2O3 NPs were instilled to female Wistar rats at 7.5, 30, and 90 cm2/rat and lung injuries were evaluated at day 1, 3, 7, 14, 30, 90, and 180 after a single intratracheal instillation. Treatment of In2O3 NPs induced worsening diverse pathological changes including PAP, persistent neutrophilic inflammation, type II cell hyperplasia, foamy macrophages, and granulomas in a time- and dose-dependent manner. PAP was induced from day 3 and worsened throughout the study. The concentrations of interleukin-1ß, tumor necrosis factor-α, and monocyte chemoattractant protein-1 in bronchoalveolar lavage fluid (BALF) showed dose- and time-dependent increases and the levels of these inflammatory mediators are consistent with the data of inflammatory cells in BALF and progressive lung damages by In2O3 NPs. This study suggests that a single inhalation exposure to In2O3 NPs can produce worsening lung damages such as PAP, chronic active inflammation, infiltration of foamy macrophages, and granulomas. The early onset and persistent PAP even at the very low dose (7.5 cm2/rat) implies that the re-evaluation of occupational recommended exposure limit for In2O3 NPs is urgently needed to protect workers.

Secondary pulmonary alveolar proteinosis during corticosteroid therapy for organising pneumonia associated with myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) is frequently complicated by pulmonary disease. Here, we describe secondary pulmonary alveolar proteinosis (sPAP) that developed during corticosteroid therapy for organising pneumonia (OP) associated with MDS. A 75-year-old woman with MDS complained of cough for 2 weeks. Chest CT showed bilateral patchy consolidations with reversed halo sign. Bronchoalveolar lavage (BAL) examination showed remarkably increased cell density with an increased lymphocyte proportion. Abnormal radiological findings improved rapidly on administration of systemic corticosteroid under the diagnosis of OP; however, they relapsed a few weeks later. Transbronchial lung biopsy showed periodic acid-Schiff stain-positive amorphous materials. Autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF) in serum and BAL fluid (BALF) were both negative, while GM-CSF level in BALF was elevated. The patient was diagnosed with sPAP. When chest radiological findings show exacerbation during corticosteroid therapy for OP in a patient with MDS, physicians should consider sPAP complication as a differential diagnosis.

Autoimmune Pulmonary Alveolar Proteinosis Diagnosed after Exposure to a Fire Extinguisher Containing Silica Powder.

We herein report a case of autoimmune pulmonary alveolar proteinosis (PAP) diagnosed after one-time exposure to silica powder. Owing to the misuse of a silica-containing fire extinguisher and the inhalation of large amounts of its powder, the patient experienced prolonged cough and visited our hospital. The findings of chest computed tomography and surgical lung biopsy specimens led to the diagnosis of PAP. Interestingly, the presence of anti-GM-CSF antibody was detected; therefore, both autoimmune characteristics and exposure to large amounts of silica may have caused the development of PAP in this patient. This case provides important insight into the mechanisms leading to the onset of PAP.

New interplay between interstitial and alveolar macrophages explains pulmonary alveolar proteinosis (PAP) induced by indium tin oxide particles.

Occupational exposure to indium tin oxide (ITO) particles has been associated with the development of severe lung diseases, including pulmonary alveolar proteinosis (PAP). The mechanisms of this lung toxicity remain unknown. Here, we reveal the respective roles of resident alveolar (Siglec-Fhigh AM) and recruited interstitial (Siglec-Flow IM) macrophages contributing in concert to the development of PAP. In mice treated with ITO particles, PAP is specifically associated with IL-1α (not GM-CSF) deficiency and Siglec-Fhigh AM (not Siglec-Flow IM) depletion. Mechanistically, ITO particles are preferentially phagocytosed and dissolved to soluble In3+ by Siglec-Flow IM. In contrast, Siglec-Fhigh AM weakly phagocytose or dissolve ITO particles, but are sensitive to released In3+ through the expression of the transferrin receptor-1 (TfR1). Blocking pulmonary Siglec-Flow IM recruitment in CCR2-deficient mice reduces ITO particle dissolution, In3+ release, Siglec-Fhigh AM depletion, and PAP formation. Restoration of IL-1-related Siglec-Fhigh AM also prevented ITO-induced PAP. We identified a new mechanism of secondary PAP development according to which metal ions released from inhaled particles by phagocytic IM disturb IL-1α-dependent AM self-maintenance and, in turn, alveolar clearance.

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.

A Suspected Case of an Alveolar Haemorrhage Caused by Dasatinib.

A 39-year-old man treated with dasatinib for chronic myelogenous leukaemia presented to our hospital with haemoptysis, coughing, and dyspnoea. Chest radiography and computed tomography revealed ground-glass opacities and a crazy-paving pattern. Bronchoalveolar lavage was not performed due to serious hypoxemia and bleeding. Significant bleeding from the peripheral bronchi led to a diagnosis of an alveolar haemorrhage. Dasatinib-induced alveolar haemorrhaging was suspected based on the clinical findings. His condition improved immediately after dasatinib withdrawal and initiation of steroid therapy. Reports of alveolar haemorrhaging induced by dasatinib are rare. As such, this is considered an important case.

Fibrotic gene expression coexists with alveolar proteinosis in early indium lung.

Occupational inhalation of indium compounds can cause the so-called "indium lung disease". Most affected individuals show pulmonary alveolar proteinosis (PAP) and fibrotic interstitial lung disease. In animal experiments, inhalation of indium tin oxide or indium oxide has been shown to cause lung damage. However, the mechanisms by which indium compounds lead to indium lung disease remain unknown. In this study, we constructed a mouse model of indium lung disease and analyzed gene expression in response to indium exposure. Indium oxide (In2O3, 10 mg/kg, primary particle size <100 nm) was administered intratracheally to C57BL/6 mice (male, 8 weeks of age) twice a week for 8 weeks. Four weeks after the final instillation, histopathological analysis exhibited periodic acid-Schiff positive material in the alveoli, characteristic of PAP. Comprehensive gene expression analysis by RNA-Seq, however, revealed expression of fibrosis-related genes, such as surfactant associated protein D, surfactant associated protein A1, mucin 1, and collagen type I and III, was significantly increased, indicating that fibrotic gene expression progresses in early phase of indium lung. These data supported the latest hypothesis that PAP occurs as an acute phase response and is replaced by fibrosis after long-term latency.

An unusual cause of respiratory failure in a 25-year-old heart and lung transplant recipient.

A 25-year-old woman, a never smoker with a history of heart-lung transplantation for World Health Organization group 1 pulmonary arterial hypertension performed 20 months prior to presentation, was evaluated for shortness of breath. Following transplantation, she was initiated on standard therapy of prednisone, tacrolimus, and azathioprine, along with routine antimicrobial prophylaxis. Her posttransplant course was complicated by persistent acute cellular rejection, as determined from a transbronchial biopsy specimen, without evidence of rejection in an endomyocardial biopsy specimen. The immunosuppressive medications were supplemented with pulse-dosed steroids, and the patient was transitioned from azathioprine to mycophenolate mofetil. Sirolimus was added 9 months prior to presentation. Three months prior to presentation, she was admitted for increasing oxygen requirements, shortness of breath, and bilateral infiltrates on the CT scans of the chest.

IL-1α induces CD11b(low) alveolar macrophage proliferation and maturation during granuloma formation.

Macrophages play a central role in immune and tissue responses of granulomatous lung diseases induced by pathogens and foreign bodies. Circulating monocytes are generally viewed as central precursors of these tissue effector macrophages. Here, we provide evidence that granulomas derive from alveolar macrophages serving as a local reservoir for the expansion of activated phagocytic macrophages. By exploring lung granulomatous responses to silica particles in IL-1-deficient mice, we found that the absence of IL-1α, but not IL-1ß, was associated with reduced CD11b(high) phagocytic macrophage accumulation and fewer granulomas. This defect was associated with impaired alveolar clearance and resulted in the development of pulmonary alveolar proteinosis (PAP). Reconstitution of IL-1α(-/-) mice with recombinant IL-1α restored lung clearance functions and the pulmonary accumulation of CD11b(high) phagocytic macrophages. Mechanistically, IL-1α induced the proliferation of CD11b(low) alveolar macrophages and differentiated these cells into CD11b(high) macrophages which perform critical phagocytic functions and organize granuloma. We newly discovered here that IL-1α triggers lung responses requiring macrophage proliferation and maturation from tissue-resident macrophages.