Pulmonary alveolar proteinosis

Enhancing the clinical activity of granulocyte-macrophage colony-stimulating factor-secreting tumor cell vaccines

A comparative analysis of vaccination with irradiated, murine tumor cells engineered to express a large number of immunostimulatory molecules established the superior ability of granulocyte-macrophage colony-stimulating factor (GM-CSF) to evoke potent, specific, and long-lasting anti-tumor immunity. Early stage clinical testing of this vaccination strategy in patients with diverse solid and hematologic malignancies revealed the consistent induction of a coordinated humoral and cellular reaction that effectuated substantial tumor destruction. Nonetheless, most subjects eventually succumbed to progressive disease, implying that additional immune defects remained to be addressed. More detailed investigations of the mechanisms underlying protective immunity in murine systems together with the characterization of the anti-tumor reactions of patients who achieved durable clinical benefits in response to immunotherapy uncovered several pathways that restrain the efficacy of GM-CSF-secreting tumor cell vaccines. These include milk fat globule epidermal growth factor protein-8 expansion of forkhead box protein 3+ regulatory T cells, cytotoxic T-lymphocyte antigen-4-mediated negative costimulation, and soluble major histocompatibility complex class I chain-related protein A suppression of NKG2D-dependent innate and adaptive anti-tumor cytotoxicity. Together, these results define key regulatory circuits that attenuate immune-mediated tumor destruction and suggest novel combinatorial therapies that might enhance the clinical activity of GM-CSF-secreting tumor cell vaccines.

Genetic disorders of surfactant dysfunction

Mutations in the genes encoding the surfactant proteins B and C (SP-B and SP-C) and the phospholipid transporter, ABCA3, are associated with respiratory distress and interstitial lung disease in the pediatric population. Expression of these proteins is regulated developmentally, increasing with gestational age, and is critical for pulmonary surfactant function at birth. Pulmonary surfactant is a unique mixture of lipids and proteins that reduces surface tension at the air-liquid interface, preventing collapse of the lung at the end of expiration. SP-B and ABCA3 are required for the normal organization and packaging of surfactant phospholipids into specialized secretory organelles, known as lamellar bodies, while both SP-B and SP-C are important for adsorption of secreted surfactant phospholipids to the alveolar surface. In general, mutations in the SP-B gene SFTPB are associated with fatal respiratory distress in the neonatal period, and mutations in the SP-C gene SFTPC are more commonly associated with interstitial lung disease in older infants, children, and adults. Mutations in the ABCA3 gene are associated with both phenotypes. Despite this general classification, there is considerable overlap in the clinical and histologic characteristics of these genetic disorders. In this review, similarities and differences in the presentation of these disorders with an emphasis on their histochemical and ultrastructural features will be described, along with a brief discussion of surfactant metabolism. Mechanisms involved in the pathogenesis of lung disease caused by mutations in these genes will also be discussed.

Molecular Basis of Pulmonary Disease

Pulmonary pathology includes a large spectrum of both neoplastic and non-neoplastic diseases that affect the lung. Many of these are a result of the unusual relationship of the lung with the outside world. Every breath that a human takes brings the outside world into the body in the form of infectious agents, organic and inorganic particles, and noxious agents of all types. Although the lung has many defense mechanisms to protect itself from these insults, these are not infallible; therefore, lung pathology arises. Damage to the lung is particularly important given the role of the lung in the survival of the organism. Any impairment of lung function has widespread effects throughout the body, since all organs depend on the lungs for the oxygen they need. Pulmonary pathology catalogs the changes in the lung tissues and the mechanisms through which these occur. This chapter presents a review of lung pathology and the current state of knowledge about the pathogenesis of each disease. It suggests that a clear understanding of both morphology and mechanism is required for the development of new therapies and preventive measures.

Incomplete inhibition of sphingosine 1-phosphate lyase modulates immune system function yet prevents early lethality and non-lymphoid lesions

Background

S1PL is an aldehyde-lyase that irreversibly cleaves sphingosine 1-phosphate (S1P) in the terminal step of sphingolipid catabolism. Because S1P modulates a wide range of physiological processes, its concentration must be tightly regulated within both intracellular and extracellular environments.

Methodology

In order to better understand the function of S1PL in this regulatory pathway, we assessed the in vivo effects of different levels of S1PL activity using knockout (KO) and humanized mouse models.

Principal Findings

Our analysis showed that all S1PL-deficient genetic models in this study displayed lymphopenia, with sequestration of mature T cells in the thymus and lymph nodes. In addition to the lymphoid phenotypes, S1PL KO mice (S1PL^−/−) also developed myeloid cell hyperplasia and significant lesions in the lung, heart, urinary tract, and bone, and had a markedly reduced life span. The humanized knock-in mice harboring one allele (S1PL^H/−) or two alleles (S1PL^H/H) of human S1PL expressed less than 10 and 20% of normal S1PL activity, respectively. This partial restoration of S1PL activity was sufficient to fully protect both humanized mouse lines from the lethal non-lymphoid lesions that developed in S1PL^−/− mice, but failed to restore normal T-cell development and trafficking. Detailed analysis of T-cell compartments indicated that complete absence of S1PL affected both maturation/development and egress of mature T cells from the thymus, whereas low level S1PL activity affected T-cell egress more than differentiation.

Significance

These findings demonstrate that lymphocyte trafficking is particularly sensitive to variations in S1PL activity and suggest that there is a window in which partial inhibition of S1PL could produce therapeutic levels of immunosuppression without causing clinically significant S1P-related lesions in non-lymphoid target organs.

Anaesthesia for serial whole-lung lavage in a patient with severe pulmonary alveolar proteinosis: a case report

INTRODUCTION

Pulmonary alveolar proteinosis is a rare condition that requires treatment by whole-lung lavage. We report a case of severe pulmonary alveolar proteinosis and discuss a safe and effective strategy for the anaesthetic management of patients undergoing this complex procedure.

CASE PRESENTATION

A 34-year-old Caucasian man was diagnosed with severe pulmonary alveolar proteinosis. He developed severe respiratory failure and subsequently underwent serial whole-lung lavage. Our anaesthetic technique included the use of pre-oxygenation, complete lung separation with a left-sided double-lumen endotracheal tube, one-lung ventilation with positive end-expiratory pressure, appropriate ventilatory monitoring, cautious use of positional manoeuvres and single-lumen endotracheal tube exchange for short-term postoperative ventilation.

CONCLUSION

Patients with pulmonary alveolar proteinosis may present with severe respiratory failure and require urgent whole-lung lavage. We have described a safe and effective strategy for anaesthesia for whole-lung lavage. We recommend our anaesthetic technique for patients undergoing this complex and uncommon procedure.

Out of breath: GM-CSFRalpha mutations disrupt surfactant homeostasis

Pulmonary alveolar proteinosis (PAP) is a rare disorder in which surfactant homeostasis in the lung is impaired, causing respiratory distress and, in severe cases, respiratory failure. Most cases of PAP are associated with the formation of autoantibodies against the cytokine granulocyte/macrophage colony-stimulating factor (GM-CSF), which is required for normal surfactant homeostasis and lung function. New studies now identify three patients in whom PAP was caused by mutations in the gene encoding the ligand-binding α chain of the GM-CSF receptor.

Familial pulmonary alveolar proteinosis caused by mutations in CSF2RA

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-Rα) and nonbinding affinity-enhancing (GM-CSF-Rβ) 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-Rα–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-Rα, 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.

Pulmonary alveolar proteinosis caused by deletion of the GM-CSFRalpha gene in the X chromosome pseudoautosomal region 1

Pulmonary alveolar proteinosis (PAP) is a rare lung disorder in which surfactant-derived lipoproteins accumulate excessively within pulmonary alveoli, causing severe respiratory distress. The importance of granulocyte/macrophage colony-stimulating factor (GM-CSF) in the pathogenesis of PAP has been confirmed in humans and mice, wherein GM-CSF signaling is required for pulmonary alveolar macrophage catabolism of surfactant. PAP is caused by disruption of GM-CSF signaling in these cells, and is usually caused by neutralizing autoantibodies to GM-CSF or is secondary to other underlying diseases. Rarely, genetic defects in surfactant proteins or the common β chain for the GM-CSF receptor (GM-CSFR) are causal. Using a combination of cellular, molecular, and genomic approaches, we provide the first evidence that PAP can result from a genetic deficiency of the GM-CSFR α chain, encoded in the X-chromosome pseudoautosomal region 1.

Recurrent pulmonary alveolar proteinosis secondary to agammaglobulinemia

Pulmonary alveolar proteinosis (PAP) is characterized by the accumulation of surfactant derived material in the lung of patients. PAP is rare in children. The patient presented with respiratory failure. In the history she was diagnosed with agammaglobulinemia at 8 months of age and has been treated by IVIG once in a month. She had two pulmonary alveolary proteinosis attacks before. Chest X-ray showed bilateral diffuse infiltrates. Initial diagnosis were pneumonia, ARDS, and lung edema. Whole-lung lavage revealed lipoproteinaceous material similar to surfactant. This findings and high level of LDH was as evaluated pulmonary alveolary proteinosis. She discharged from the hospital without any respiratory complication on the ninth day. This is the first case report recurrent PAP associated with agammaglobulinemia.

Pulmonary alveolar proteinosis in pediatric leukemia

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by intra-alveolar accumulation of periodic acid-Schiff (PAS)-positive surfactant components. Leukemia is the cancer most often associated with PAP; prolonged neutropenia and reduction of alveolar macrophages by myeloablative chemotherapy or leukemic infiltration are implicated. Only isolated cases of PAP have been reported, and pediatric experience is limited.

PROCEDURE

We reviewed all pathology records (1962-2007) of St. Jude Children's Research Hospital to identify patients with PAP.

RESULTS

Five patients had PAP. As expected, all had leukemia and had profound neutropenia at onset of PAP. A diagnosis was made only after PAS staining of bronchoalveolar lavage (BAL), lung biopsy, or autopsy specimens. Two patients had Down syndrome, which is not known to be associated with PAP. The other three patients had undergone hematopoietic stem cell transplantation (HSCT). Two patients showed clinical improvement or histological disappearance of PAP after neutropenia resolved.

CONCLUSIONS

PAP should be considered in the differential diagnosis of severe respiratory symptoms in neutropenic patients with hematologic malignancy, especially those with Down syndrome, a history of HSCT, or active disease. PAP should be confirmed by PAS staining of a BAL or lung biopsy specimen.

Gene therapy of beta(c)-deficient pulmonary alveolar proteinosis (beta(c)-PAP): studies in a murine in vivo model

Pulmonary alveolar proteinosis (PAP) due to deficiency of the common beta-chain (beta(c)) of the interleukin-3 (IL-3)/IL-5/granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors is a rare monogeneic disease characterized by functional insufficiency of pulmonary macrophages. Hematopoietic stem cell gene therapy for restoring expression of beta(c)-protein in the hematopoietic system may offer a curative approach. Toward this end, we generated a retroviral construct expressing the murine beta(c) (mbeta(c)) gene and conducted investigations in a murine model of beta(c)-deficient PAP. Functional correction of mbeta(c) activity in mbeta(c)(-/-) bone marrow (BM) cells was demonstrated by restoration of in vitro colony formation in response to GM-CSF. In addition, in a murine in vivo model of mbeta(c)-deficient PAP mbeta(c) gene transfer to hematopoietic stem cells not only restored the GM-CSF-sensitivity of hematopoietic progenitor cells but also, within a period of 12 weeks, almost completely reversed the morphologic features of surfactant accumulation. These results were obtained despite modest transduction levels (10-20%) and, in comparison to wild-type mice, clearly reduced beta(c) expression levels were detected in hematopoietic cells. Therefore, our data demonstrating genetic and functional correction of mbeta(c)(-/-) deficiency in vitro as well as in a murine in vivo model of PAP strongly suggest gene therapy as a potential new treatment modality in beta(c)-deficient PAP.

Pulmonary Alveolar Proteinosis in Extremis: The Case for Aggressive Whole Lung Lavage with Extracorporeal Membrane Oxygenation Support

Pulmonary alveolar proteinosis (PAP) is a rare disorder in which lipoproteinaceous material is deposited in the alveoli, compromising gaseous exchange. We report the case of a 29-year-old female patient presenting with the most extreme case of PAP yet reported. She successfully managed by aggressive bilateral whole lung lavage (WLL) in a single sitting using extracorporeal membrane oxygenation (ECMO) support. Despite critical hypercarbia and ventilator-dependence for 12 days before lavage, the patient experienced rapid recovery of pulmonary function after WLL and ECMO could be discontinued on-table. Aggressive WLL with ECMO support can be safe and effective even in the most severe cases of PAP.

Iron homeostasis and oxidative stress in idiopathic pulmonary alveolar proteinosis: a case-control study

BACKGROUND

Lung injury caused by both inhaled dusts and infectious agents depends on increased availability of iron and metal-catalyzed oxidative stress. Because inhaled particles, such as silica, and certain infections can cause secondary pulmonary alveolar proteinosis (PAP), we tested the hypothesis that idiopathic PAP is associated with an altered iron homeostasis in the human lung.

METHODS

Healthy volunteers (n = 20) and patients with idiopathic PAP (n = 20) underwent bronchoalveolar lavage and measurements were made of total protein, iron, tranferrin, transferrin receptor, lactoferrin, and ferritin. Histochemical staining for iron and ferritin was done in the cell pellets from control subjects and PAP patients, and in lung specimens of patients without cardiopulmonary disease and with PAP. Lavage concentrations of urate, glutathione, and ascorbate were also measured as indices of oxidative stress.

RESULTS

Lavage concentrations of iron, transferrin, transferrin receptor, lactoferrin, and ferritin were significantly elevated in PAP patients relative to healthy volunteers. The cells of PAP patients had accumulated significant iron and ferritin, as well as considerable amounts of extracellular ferritin. Immunohistochemistry for ferritin in lung tissue revealed comparable amounts of this metal-storage protein in the lower respiratory tract of PAP patients both intracellularly and extracellularly. Lavage concentrations of ascorbate, glutathione, and urate were significantly lower in the lavage fluid of the PAP patients.

CONCLUSION

Iron homeostasis is altered in the lungs of patients with idiopathic PAP, as large amounts of catalytically-active iron and low molecular weight anti-oxidant depletion are present. These findings suggest a metal-catalyzed oxidative stress in the maintenance of this disease.

Characteristics of a large cohort of patients with autoimmune pulmonary alveolar proteinosis in Japan

RATIONALE

Acquired pulmonary alveolar proteinosis (PAP) is a syndrome characterized by pulmonary surfactant accumulation occurring in association with granulocyte/macrophage colony-stimulating factor autoantibodies (autoimmune PAP) or as a consequence of another disease (secondary PAP). Because PAP is rare, prior reports were based on limited patient numbers or a synthesis of historical data.

OBJECTIVES

To describe the epidemiologic, clinical, physiologic, and laboratory features of autoimmune PAP in a large, contemporaneous cohort of patients with PAP.

METHODS

Over 6 years, 248 patients with PAP were enrolled in a Japanese national registry, including 223 with autoimmune PAP.

MEASUREMENTS AND MAIN RESULTS

Autoimmune PAP represented 89.9% of cases and had a minimum incidence and prevalence of 0.49 and 6.2 per million, respectively. The male to female ratio was 2.1:1, and the median age at diagnosis was 51 years. A history of smoking occurred in 56%, and dust exposure occurred in 23%; instances of familial onset did not occur. Dyspnea was the most common presenting symptom, occurring in 54.3%. Importantly, 31.8% of patients were asymptomatic and were identified by health screening. Intercurrent illnesses, including infections, were infrequent. A disease severity score reflecting the presence of symptoms and degree of hypoxemia correlated well with carbon monoxide diffusing capacity and serum biomarkers, less well with pulmonary function, and not with granulocyte/macrophage colony-stimulating factor autoantibody levels or duration of disease.

CONCLUSIONS

Autoimmune PAP had an incidence and prevalence higher than previously reported and was not strongly linked to smoking, occupational exposure, or other illnesses. The disease severity score and biomarkers provide novel and potentially useful outcome measures in PAP.

Genetic Abnormalities of Surfactant Metabolism

Pulmonary surfactant is the complex mixture of lipids and proteins needed to reduce alveolar surface tension at the air-liquid interface and prevent alveolar collapse at the end of expiration. It has been recognized for almost 50 years that a deficiency in surfactant production due to pulmonary immaturity is the principal cause of the respiratory distress syndrome (RDS) observed in prematurely born infants.1 Secondary surfactant deficiency due to injury to the cells involved in its production and functional inactivation of surfactant is also important in the pathophysiology of acute respiratory distress syndrome (ARDS) observed in older children and adults.2,3 In the past 15 years, it has been recognized that surfactant deficiency may result from genetic mechanisms involving mutations in genes encoding critical components of the surfactant system or proteins involved in surfactant metabolism.4,5 Although rare, these single gene disorders provide important insights into normal surfactant metabolism and into the genes in which frequently occurring allelic variants may be important in more common pulmonary diseases.

Amyloid peptides and proteins in review

Amyloids are filamentous protein deposits ranging in size from nanometres to microns and composed of aggregated peptide beta-sheets formed from parallel or anti-parallel alignments of peptide beta-strands. Amyloid-forming proteins have attracted a great deal of recent attention because of their association with over 30 diseases, notably neurodegenerative conditions like Alzheimer's, Huntington's, Parkinson's, Creutzfeldt-Jacob and prion disorders, but also systemic diseases such as amyotrophic lateral sclerosis (Lou Gehrig's disease) and type II diabetes. These diseases are all thought to involve important conformational changes in proteins, sometimes termed misfolding, that usually produce beta-sheet structures with a strong tendency to aggregate into water-insoluble fibrous polymers. Reasons for such conformational changes in vivo are still unclear. Intermediate aggregated state(s), rather than precipitated insoluble polymeric aggregates, have recently been implicated in cellular toxicity and may be the source of aberrant pathology in amyloid diseases. Numerous in vitro studies of short and medium length peptides that form amyloids have provided some clues to amyloid formation, with an alpha-helix to beta-sheet folding transition sometimes implicated as an intermediary step leading to amyloid formation. More recently, quite a few non-pathological amyloidogenic proteins have also been identified and physiological properties have been ascribed, challenging previous implications that amyloids were always disease causing. This article summarises a great deal of current knowledge on the occurrence, structure, folding pathways, chemistry and biology associated with amyloidogenic peptides and proteins and highlights some key factors that have been found to influence amyloidogenesis.

ABCG1 is deficient in alveolar macrophages of GM-CSF knockout mice and patients with pulmonary alveolar proteinosis

Patients with pulmonary alveolar proteinosis (PAP) display impaired surfactant clearance, foamy, lipid-filled alveolar macrophages, and increased cholesterol metabolites within the lung. Neutralizing autoantibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF) are also present, resulting in virtual GM-CSF deficiency. We investigated ABCG1 and ABCA1 expression in alveolar macrophages of PAP patients and GM-CSF knockout (KO) mice, which exhibit PAP-like pulmonary pathology and increased pulmonary cholesterol. Alveolar macrophages from both sources displayed a striking similarity in transporter gene dysregulation, consisting of deficient ABCG1 accompanied by highly increased ABCA1. Peroxisome proliferator-activated receptor gamma (PPARgamma), a known regulator of both transporters, was deficient, as reported previously. In contrast, the liver X receptor alpha, which also upregulates both transporters, was highly increased. GM-CSF treatment increased ABCG1 expression in macrophages in vitro and in PAP patients in vivo. Overexpression of PPARgamma by lentivirus-PPARgamma transduction of primary alveolar macrophages, or activation by rosiglitazone, also increased ABCG1 expression. These results suggest that ABCG1 deficiency in PAP and GM-CSF KO alveolar macrophages is attributable to the absence of a GM-CSF-mediated PPARgamma pathway. These findings document the existence of ABCG1 deficiency in human lung disease and highlight a critical role for ABCG1 in surfactant homeostasis.

Efficient targeting to alveolar macrophages by intratracheal administration of mannosylated liposomes in rats

The success of targeting systems to alveolar macrophages critically depends on internalization into these cells for pharmacological intervention. Direct respiratory delivery via inhalation of mannose modified liposomal carriers to alveolar macrophages is of great interest. To evaluate the targeting efficiency to alveolar macrophages by intratracheal administration of mannosylated liposomes (Man-liposomes), Man-liposomes with various ratio of mannosylated cholesterol derivatives, cholesten-5-yloxy-N-(4-((1-imino-2-D-thiomannosylethyl)amino)alkyl)formamide (Man-C4-Chol) as mannose receptor ligand were investigated with regard to their in vitro uptake in primary cultured alveolar macrophages and in vivo intratracheal administration in rats. The in vitro uptake of Man-liposomes took place in a concentration-dependent manner. The internalization of Man-liposomes with 7.5% (Man-7.5-liposomes) and 5.0% (Man-5.0-liposomes) Man-C4-Chol was considerably higher than that of Man-liposomes with 2.5% of Man-C4-Chol (Man-2.5-liposomes) and Bare-liposomes and significantly inhibited by an excess of mannan, suggesting mannose receptor-mediated endocytosis. After intratracheal administration of Man-7.5 and Man-5.0-liposomes in rats, a significantly high internalization and selective targeting to alveolar macrophages was observed. The enhanced cellular uptake in alveolar macrophages related to the mannose density of Man-liposomes was also confirmed both in vitro and in vivo confocal microscopy studies. These results demonstrate the efficient targeting to alveolar macrophages by the intratracheally administered Man-liposomes via mannose receptor-mediated endocytosis.

Lung cancer may develop subsequently or coincidently with pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by an accumulation of periodic acid-Schiff (PAS) positive lipoproteinaceous material in the alveolar space. It is usually idiopathic, and secondary to hematologic malignancy or some atypical infection. To date, there are only five published case reports of PAP occurring in association with solid organ cancer. We herein report two cases of PAP associated with lung cancer: one, a case of idiopathic PAP with subsequent development of lung cancer, and the other, a case of coexisting lung cancer and PAP. In conclusion, PAP can occur prior to or coincidently with lung cancer.

Integrin beta6 mediates phospholipid and collectin homeostasis by activation of latent TGF-beta1

Surfactant lines the alveolar surface and prevents alveolar collapse. Derangements of surfactant cause respiratory failure and interstitial lung diseases. The collectins, surfactant proteins A and D, are also important in innate host defense. However, surfactant regulation in the postnatal lung is poorly understood. We found that the epithelial integrin, alphavbeta6, regulates surfactant homeostasis in vivo by activating latent transforming growth factor (TGF)-beta. Adult mice lacking the beta-subunit of alphavbeta6 (Itgb6-/-) developed increased bronchoalveolar lavage phospholipids and surfactant proteins A and D, and demonstrated abnormal-appearing alveolar macrophages, reminiscent of the human disease pulmonary alveolar proteinosis. Using lung-specific expression of constitutively active TGF-beta1 in Itgb6-/- mice, we found that TGF-beta1 was sufficient to normalize these abnormalities. Tgfbeta1-deficient mice also demonstrated increased phospholipids and surfactant proteins A and D, but mice lacking the key TGF-beta signaling molecule, SMAD3, did not. Therefore, integrin-mediated activation of latent TGF-beta1 regulates surfactant constituents independent of intracellular SMAD3. In vivo increases in surfactant protein A and D were not associated with increases in mRNA for these proteins in alveolar tissue from Itgb6-/- mice. On the other hand, isolated alveolar macrophages from Itgb6-/- mice were defective in processing phospholipids in vitro, suggesting that reduced surfactant clearance contributes to altered surfactant homeostasis in these mice in vivo. These findings show that alphavbeta6 and TGF-beta1 regulate homeostasis of phospholipids and collectins in adult mouse lungs and may have implications for anti-fibrotic therapeutics that inhibit active TGF-beta in the lung.

Endotoxin-induced maturation of monocytes in preterm fetal sheep lung

The fetal lung normally contains immature monocytes and very few mature macrophages. The chorioamnionitis frequently associated with preterm birth induces monocyte influx into the fetal lung. Previous studies demonstrated that monocytes in the developing lung can mediate lung injury responses that resemble BPD in humans. We hypothesized that chorioamnionitis would induce maturation of immature monocytes in the fetal lung. Groups of three to seven time-mated ewes received saline or 10 mg of endotoxin (Escherichia coli 055:B5) in saline by intra-amniotic injection for intervals from 1 to 14 days before operative delivery at 124 days of gestational age. Monocytic cells from lung tissue were recovered using Percoll gradients. Monocytic cells consistent with macrophages were identified morphologically and by myosin heavy chain class II expression. An increase in macrophages was preceded by induction of granulocyte-macrophage colony-stimulating factor in the lung and subsequent activation of the transcription factor PU.1. The production of IL-6 by monocytes/macrophages in response to endotoxin challenge in vitro increased 7 and 14 days after exposure to intra-amniotic endotoxin. Recombinant TNF-alpha induced IL-6 production by lung monocytic cells exposed to intra-amniotic endotoxin but not in control cells. Monocytic phagocytosis of apoptotic neutrophils also increased 7 and 14 days after exposure to intra-amniotic endotoxin. Intra-amniotic endotoxin induced lung monocytes to develop into functionally mature cells consistent with macrophages. These findings have implications for lung immune responses after exposure to chorioamnionitis.

Role of granulocyte macrophage colony-stimulating factor in host defense against pulmonary Cryptococcus neoformans infection during murine allergic bronchopulmonary mycosis

We investigated the role of granulocyte macrophage colony-stimulating factor (GM-CSF) in host defense in a murine model of pulmonary cryptococcosis induced by intratracheal inoculation of Cryptococcus neoformans. Pulmonary C. neoformans infection of C57BL/6 mice is an established model of an allergic bronchopulmonary mycosis. Our objective was to determine whether GM-CSF regulates the pulmonary Th2 immune response in C. neoformans-infected C57BL/6 mice. Long-term pulmonary fungistasis was lost in GM-CSF knockout (GM(-/-)) mice, resulting in increased pulmonary burden of fungi between weeks 3 and 5. GM-CSF was required for the early influx of macrophages and CD4 and CD8 T cells into the lungs but was not required later in the infection. Lack of GM-CSF also resulted in reduced eosinophil recruitment and delayed recruitment of mononuclear cells into the airspace. Macrophages from GM(+/+) mice showed numerous hallmarks of alternatively activated macrophages: higher numbers of intracellular cryptococci, YM1 crystals, and induction of CCL17. These hallmarks are absent in macrophages from GM(-/-) mice. Mucus-producing goblet cells were abundantly present within the bronchial epithelial layer in GM(+/+) mice but not in GM(-/-) mice at week 5 after infection. Production of both Th1 and Th2 cytokines was impaired in the absence of GM-CSF, consistent with both reduced C. neoformans clearance and absence of allergic lung pathology.

Expression of PU.1 and terminal differentiation of alveolar macrophages in newborn rats

PU.1, which is a transcription factor, promotes the terminal differentiation of alveolar macrophages (AMs). Its expression is regulated by granulocyte/macrophage colony-stimulating factor (GM-CSF). In this study of AMs in newborn rats, we performed immunohistochemical staining, acid phosphatase staining, reverse transcriptase polymerase chain reaction (RT-PCR), quantitative real-time PCR, cytokine assay, and electron microscopy. AMs at 3 and 7 days after birth had a large foamy appearance with an intracytoplasmic accumulation of surfactants. Weak expression of PU.1 was observed in the nuclei. AMs at 15 days after birth were smaller, and PU.1 expression had increased. Ultrastructurally, AMs at 1 day after birth had a smooth surface and abundant lamellar structures in the cytoplasm, whereas AMs at 56 days after birth were characterized by (1) abundant microvillar projections on the cell surface, and (2) well-developed lysosomes and a few lamellar structures in the cytoplasm. Acid phosphatase activity and the expression of mannose receptor, scavenger receptor, and GM-CSF receptor alpha were enhanced in AMs with time after birth. These results suggest that AMs are initially immature, and that their terminal differentiation starts after birth concomitantly with an increased expression of PU.1.

Elevated BALF concentrations of α- and β-defensins in patients with pulmonary alveolar proteinosis

Defensins are endogenous antibiotics and regulators of inflammation, immunity and wound repair. Their concentrations are substantially increased in bronchoalveolar lavage fluid (BALF) of patients with infectious lung diseases. alpha-defensin (HAD) levels are also elevated in patients with idiopathic pulmonary fibrosis (IPF) and correlated with the decline in pulmonary function tests, suggesting the association of defensins with the pathogenesis of interstitial lung diseases. The aim of this study was to determine the profile of defensins in interstitial lung diseases. Serum and BALF levels of HAD and beta-defensin 1 and 2 (HBD-1, and -2) were measured by radioimmunoassay in 63 patients with interstitial lung diseases, including idiopathic pulmonary alveolar proteinosis (PAP), IPF, nonspecific interstitial pneumonia (NSIP), cryptogenic organizing pneumonia (COP) and pulmonary sarcoidosis, and in 9 healthy volunteers as controls. Levels of HAD in BALF of patients with PAP were significantly higher than those in controls and patients with COP and sarcoidosis. Serum levels of HAD in all groups were significantly higher than those in controls. Levels of HBD-1 and -2 in BALF of patients with PAP were extremely high in all subjects. Serum levels of HBD-1 were higher in all patient groups, with the exception of those with PAP, and those of HBD-2 were also higher in patients with IPF and sarcoidosis, compared with controls. BALF of PAP patients, but not IPF patients and controls, expressed antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus. Our findings suggest different kinetics of HAD and HBD-1 and -2 in serum and BALF of interstitial lung diseases and that these antimicrobial peptides in the airway lumen may contribute to prevention of bacterial airway infections in PAP.

Successful whole lung lavage in pulmonary alveolar proteinosis secondary to lysinuric protein intolerance: a case report

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.

Alveolar macrophages from normal subjects lack the NOS-related system y+ for arginine transport

Systems y+ and y+L represent the main routes for arginine transport in mammalian cells. While system y+ activity is needed for the stimulated NO production in rodent alveolar macrophages (AM), no information is yet available about arginine transport in human AM. We study here arginine influx and genes for arginine transporters in AM from bronchoalveolar lavage of normal subjects. These cells express the y+ -related genes SLC7A1/CAT1 and SLC7A2/CAT2B, as well as the y+L genes SLC7A7/y+LAT1 and SLC7A6/y+LAT2. However, compared with human endothelial cells, AM express much less SLC7A2 mRNA and higher levels of SLC7A7 mRNA. Granulocyte macrophage colony-stimulating factor or IFN-gamma do not change the expression of any transporter gene, while lipopolysaccharide induces SLC7A2/CAT2B. Under all the conditions tested, leucine inhibits most of the arginine transport in the presence of Na+ and N-ethylmaleimide, an inhibitor of system y+, is completely ineffective, indicating that system y+L operates most of the arginine influx. Comparable results are obtained in AM from patients with interstitial lung disease, such as Nonspecific Interstitial Pneumonia (NSIP), although these cells have a higher SLC7A1 and a lower SLC7A7 expression than AM from normal subjects. It is concluded that AM from normal subjects or patients with NSIP lack a functional transport system y+, a situation that may limit arginine availability for NO synthesis. Moreover, since mutations of SLC7A7/y+LAT1 cause Lysinuric Protein Intolerance, a disease often associated with AM impairment and alveolar proteinosis, the high SLC7A7 expression observed in human AM suggests that y+LAT1 activity is important for the function of these cells.

Pulmonary alveolar proteinosis ? a rare pulmonary toxicity of sirolimus

The aim of our paper is to describe an unusual pulmonary toxicity of sirolimus (SRL) in a kidney transplant recipient. We present a 34-year-old woman with a second renal transplantation, complicated with steroid-resistant acute rejection and chronic allograft dysfunction. Two years after initiating SRL, she presented complaints of progressive dyspnoea, nonproductive cough, chest pain and low-grade fever of 1 month duration. She had chronic allograft nephropathy and slight elevation of lactic dehydrogenase levels. After exclusion of common reasons of this condition, a computed tomography (CT) of the thorax and bronchoscopy was performed, revealing ground-glass opacification with polygonal shapes on CT and an opaque appearance with numerous macrophages on bronchoalveolar lavage. The alveolar macrophages stained positive by Periodic acid-Schiff. Diagnosis of pulmonary alveolar proteinosis (PAP) was made and drug-induced toxicity was suspected. SRL was withdrawn with marked improvement in the patients' clinical and radiological status. PAP resolved within 3 months without further therapy. PAP is a very rare complication of SRL therapy with only a few cases described. Withdrawal of SRL with conversion to another immunosuppressant seems to be an appropriate procedure in this condition.

GM-CSF autoantibodies and neutrophil dysfunction in pulmonary alveolar proteinosis

BACKGROUND

Increased mortality from infection in patients with pulmonary alveolar proteinosis occurs in association with high levels of autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). We tested the hypothesis that neutrophil functions are impaired in patients with pulmonary alveolar proteinosis and that GM-CSF autoantibodies cause the dysfunction.

METHODS

We studied 12 subjects with pulmonary alveolar proteinosis, 61 healthy control subjects, and 12 control subjects with either cystic fibrosis or end-stage liver disease. We also studied GM-CSF-/- mice and wild-type mice. We evaluated basal neutrophil functions, neutrophil functions after priming by GM-CSF to augment antimicrobial functions, and the effects of highly purified GM-CSF autoantibodies on neutrophil functions in vitro and in vivo.

RESULTS

Neutrophils from subjects with pulmonary alveolar proteinosis had normal ultrastructure and differentiation markers but impaired basal functions and antimicrobial functions after GM-CSF priming. GM-CSF-/- mice also had reduced basal neutrophil functions, but functions after GM-CSF priming were unimpaired. The neutrophil dysfunction characteristic of pulmonary alveolar proteinosis was reproduced in a dose-dependent fashion in blood specimens from healthy control subjects after incubation with affinity-purified GM-CSF autoantibodies isolated from patients with pulmonary alveolar proteinosis. The injection of mouse GM-CSF antibodies into wild-type mice also caused neutrophil dysfunction.

CONCLUSIONS

The antimicrobial functions of neutrophils are impaired in patients with pulmonary alveolar proteinosis, owing to the presence of GM-CSF autoantibodies. The effects of these autoantibodies show that GM-CSF is an essential regulator of neutrophil functions.

Total lung lavage by awake flexible fiberoptic bronchoscope in a 13-year-old girl with pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare, heterogeneous diffuse lung disease in childhood. We report a case of an asymptomatic 13-year old girl with PAP. She had radiolographic findings suggesting the diagnosis, which was confirmed by the "milky" bronchoalveolar lavage fluid and the histology of transbronchial biopsy. Total lung lavage was performed by flexible fiberoptic bronchoscope under local anesthesia with success. This is the first reported case of a PAP in a child that was treated by being awake during bronchoscopy. After one-year of follow-up, the patient remains free of symptoms.

Il lavaggio broncoalveolare (BAL) in età pediatrica

Il lavaggio broncoalveolare o BAL, permettendo di ottenere le cellule ed i soluti presenti sulla superficie epiteliale del tratto respiratorio distale, si è dimostrato una metodica di ricerca essenziale per lo studio dei meccanismi eziopatogenetici delle malattie del polmone profondo, come ad esempio lo studio delle interstiziopatie, su cui esiste una vastissima letteratura di dati ottenuti con il BAL. Oltre a questo aspetto di metodica di ricerca, il BAL rappresenta perè anche una procedura diagnostica insostituibile nella pratica clinica quotidiana.

Respiratory Tract

The chapter describes different aspects of the respiratory tract. In preclinical safety studies, pathologies of the respiratory system can be a result of an intercurrent disease or can be induced by systemically administered drugs. Intranasal or inhalation modes of therapy pose particular challenges in terms of the formulations and technologies required to administer a drug. A complex technology is developed to support the assessment of adverse effects of inhaled substances in rodent and nonrodent species, and the extrapolation of experimental findings to humans. The nasal chambers are the structures that are first to be subjected to the effects of inhaled substances, whether microorganisms or chemical substances. In rodents, the relatively small size of the nose and nasal sinuses facilitates a histological examination. Findings show that infectious agents cause inflammation in the nose and nasal sinuses, and this may be associated with inflammation in the conjunctiva, the middle ear, and the oral cavity. It has been observed that a particular response of the rodent nasal mucosa to some irritant substances, including pharmaceutical agents, is the formation of rounded eosinophilic inclusions in the cytoplasm of sustentacular cells of the olfactory epithelium, and to a lesser extent in respiratory and glandular epithelial cells.