High concentration of (1-->3)-beta-D-glucan in BAL fluid in patients with acute eosinophilic pneumonia

Current and Future Pathways in Aspergillus Diagnosis

Aspergillus fumigatus has been designated by the World Health Organization as a critical priority fungal pathogen. Some commercially available diagnostics for many forms of aspergillosis rely on fungal metabolites. These encompass intracellular molecules, cell wall components, and extracellular secretomes. This review summarizes the shortcomings of antibody tests compared to tests of fungal products in body fluids and highlights the application of β-d-glucan, galactomannan, and pentraxin 3 in bronchoalveolar lavage fluids. We also discuss the detection of nucleic acids and next-generation sequencing, along with newer studies on Aspergillus metallophores.

A case of

Pneumocystis jirovecii pneumonia (PCP) in patients with acquired immune deficiency syndrome (AIDS) shows eosinophilic pneumonia like condition. The detailed mechanisms how AIDS-associated PCP causes eosinophilic pneumonia has not been elucidated, but it has been suggested that beta-D-glucan, a major component of Pneumocystis jirovecii, and T helper type 2 immunity may be involved in the mechanism of eosinophilia in the lung. We experienced the case who developed an eosinophilic pneumonia-like condition in a patient with AIDS-associated PCP, whose clinical course indicated the importance of TARC/CCL17 but not IL-4 and IL-5 as involved in eosinophilia caused by HIV and Pneumocystis jirovecii infection.

Acute Eosinophilic Pneumonia. Causes, Diagnosis, and Management

Acute eosinophilic pneumonia (AEP) is an uncommon acute respiratory illness of varying severity that includes presentation as acute respiratory distress syndrome with fatal outcome. AEP may be idiopathic, but identifiable causes include smoking and other inhalational exposures, medications, and infections. The pathogenesis of AEP is poorly understood but likely varies depending on the underlying cause. Airway epithelial injury, endothelial injury, and release of IL-33 are early events that subsequently promote eosinophil recruitment to the lung; eosinophilic infiltration and degranulation appear to mediate subsequent lung inflammation and associated clinical manifestations. Crucial for the diagnosis are the demonstration of pulmonary eosinophilia in the BAL fluid and the exclusion of other disease processes that can present with acute pulmonary infiltrates. Although peripheral blood eosinophilia at initial presentation may be a clue in suggesting the diagnosis of AEP, it may be absent or delayed, especially in smoking-related AEP. Optimal management of AEP depends on the recognition and elimination of the underlying cause when identifiable. The cessation of the exposure to the inciting agent (e.g., smoking), and glucocorticoids represent the mainstay of treating AEP of noninfectious origin. If AEP is recognized and treated in a timely manner, the prognosis is generally excellent, with prompt and complete clinical recovery, even in those patients manifesting acute respiratory failure.

Airway mycosis in allergic airway disease

The allergic airway diseases, including chronic rhinosinusitis (CRS), asthma, allergic bronchopulmonary mycosis (ABPM) and many others, comprise a heterogeneous collection of inflammatory disorders affecting the upper and lower airways and lung parenchyma that represent the most common chronic diseases of humanity. In addition to their shared tissue tropism, the allergic airway diseases are characterized by a distinct pattern of inflammation involving the accumulation of eosinophils, type 2 macrophages, innate lymphoid cells type 2 (ILC2), IgE-secreting B cells, and T helper type 2 (Th2) cells in airway tissues, and the prominent production of type 2 cytokines including interleukin (IL-) 33, IL-4, IL-5, IL-13, and many others. These factors and related inflammatory molecules induce characteristic remodeling and other changes of the airways that include goblet cell metaplasia, enhanced mucus secretion, smooth muscle hypertrophy, tissue swelling and polyp formation that account for the major clinical manifestations of nasal obstruction, headache, hyposmia, cough, shortness of breath, chest pain, wheezing, and, in the most severe cases of lower airway disease, death due to respiratory failure or disseminated, systemic disease. The syndromic nature of the allergic airway diseases that now include many physiological variants or endotypes suggests that distinct endogenous or environmental factors underlie their expression. However, findings from different perspectives now collectively link these disorders to a single infectious source, the fungi, and a molecular pathogenesis that involves the local production of airway proteinases by these organisms. In this review, we discuss the evidence linking fungi and their proteinases to the surprisingly wide variety of chronic airway and systemic disorders and the immune pathogenesis of these conditions as they relate to environmental fungi. We further discuss the important implications these new findings have for the diagnosis and future therapy of these common conditions.

β-Glucans in standardized allergen extracts

Background: Allergen extracts contain variable quantities of bacterial endotoxin. Recent studies have suggested that (1→3)-β-D-glucans (β-glucans), also microbial cell wall components, may have adjuvant properties that could affect allergen immunotherapy.

Objective: To determine the quantities of β-glucans in standardized allergen extracts.

Materials and Methods : Ninety-four lots of 13 standardized allergen extracts were tested for β-glucan content by Glucatell assay, and for endotoxin content by a specific, chromogenic formulation of the Limulus amebocyte lysate test.

Results: Standardized allergen extracts contain variable quantities of endotoxins and β-glucans. As in our previous work, endotoxin activity was greatest in cat pelt and Dermatophagoides farinae, and least in the pollens. There was no correlation between endotoxin and β-glucan levels ( r = 0.1887; P = 0.07). β-Glucan content was highest for grass pollen (median content, 10.6 ng/ml; range, 0.4—41.8 ng/ml), ragweed pollen (32.9 ng/ml; range, 6.5—41.2 ng/ml), and cat pelt (25.5 ng/ml; range, 16.7—41.1 ng/ml), and lowest for cat hair (4.9 ng/ml; range, 1.2—10.3 ng/ml), D. farinae (1.2 ng/ml; range, 0.4—5.2 ng/ml) and Dermatophagoides pteronyssinus (1.8 ng/ml; range, 0.4—6.7 ng/ml).

Conclusions: β-Glucans are present in standardized allergen extracts. The effects of these quantities of β-glucans on allergen immunotherapy and allergen skin testing require further study.

Breaking the mould - novel diagnostic and therapeutic strategies for invasive pulmonary aspergillosis in the immune deficient patient

Invasive pulmonary aspergillosis (IPA) caused by the ubiquitous environmental fungus Aspergillus is a frequently fatal lung disease of immunocompromised humans accounting for more than 200,000 infections each year, with an associated mortality rate of 30-90%. This review addresses the current status of IPA diagnosis and treatment and the urgent need to develop accurate, non-invasive strategies for identifying pulmonary infections in the ever-expanding population of immune deficient patients at risk of acquiring opportunistic fungal infections including hematological malignancy and hematopoetic stem cell transplant patients. Recent advances in the use of an Aspergillus-specific monoclonal antibody, JF5, for point-of-care diagnosis of IPA using lateral-flow technology is examined, as is its use in PET/MRI bioimaging and radio-immunotherapy using radionuclide-labeled single chain antibody fragments, Fab fragments, and a fully humanized JF5 derivative.

Inflammatory markers and pulmonary granuloma infiltration in sarcoidosis

BACKGROUND AND OBJECTIVE

Previous studies have demonstrated increases of inflammatory mediators in sarcoidosis while epidemiological studies have also demonstrated an association with increased fungi exposure. This study measured the level of β-glucan in the lungs and of inflammatory mediators in serum, and correlated both with the extent of pulmonary granuloma infiltration.

METHODS

This is a cross-sectional study of 98 patients with sarcoidosis and 26 controls. β-glucan, a cell wall constituent of fungi, was measured in bronchoalveolar lavage. Inflammatory mediator levels were determined in serum. The extent of granuloma infiltration was estimated on the chest X-ray. Exposure to fungi at home was determined by taking air samples in bedrooms and analysing for the presence of β-N-acetylhexosaminidase.

RESULTS

Significantly, higher levels of β-glucan were found in broncho-alveolar lavage in subjects with sarcoidosis as compared with controls. There were significant positive relationships between the extent of granuloma infiltration and the levels of the different inflammatory mediators, except for interleukin-10. Domestic fungal exposure was higher among subjects with sarcoidosis.

CONCLUSIONS

This is the first time that a specific agent, previously suspected to be related to the risk of sarcoidosis, has been detected in the lung of subjects with sarcoidosis and related to the levels of inflammatory mediators and the degree of home exposure to fungi. The results suggest that exposure to fungi should be explored when investigating patients with sarcoidosis.

Acute eosinophilic pneumonia

Acute eosinophilic pneumonia is a severe and rapidly progressive lung disease that can cause fatal respiratory failure. Since this disease exhibits totally different clinical features to other eosinophilic lung diseases (ELD), it is not difficult to distinguish it among other ELDs. However, this can be similar to other diseases causing acute respiratory distress syndrome or severe community-acquired pneumonia, so the diagnosis can be delayed. The cause of this disease in the majority of patients is unknown, even though some cases may be caused by smoke, other patients inhaled dust or drugs. The diagnosis is established by bronchoalveolar lavage. Treatment with corticosteroids shows a rapid and dramatic positive response without recurrence.

Eosinophilic pneumonias

This review starts with discussions of several infectious causes of eosinophilic pneumonia, which are almost exclusively parasitic in nature. Pulmonary infections due specifically to Ascaris, hookworms, Strongyloides, Paragonimus, filariasis, and Toxocara are considered in detail. The discussion then moves to noninfectious causes of eosinophilic pulmonary infiltration, including allergic sensitization to Aspergillus, acute and chronic eosinophilic pneumonias, Churg-Strauss syndrome, hypereosinophilic syndromes, and pulmonary eosinophilia due to exposure to specific medications or toxins.

Characterization of a distinct host response profile to Pneumocystis murina asci during clearance of pneumocystis pneumonia

Pneumocystis spp. are yeast-like fungi that cause pneumocystis pneumonia (PcP) in immunocompromised individuals and exacerbate chronic lung diseases in immunocompetent individuals. The Pneumocystis life cycle includes trophic forms and asci (cyst forms). The cell walls of Pneumocystis asci contain β-1,3-D-glucan, and treatment of PcP with β-1,3-D-glucan synthase inhibitors, such as anidulafungin, results in depletion of asci, but not trophic forms. The pulmonary host response during immune reconstitution (IR)-mediated clearance of PcP in anidulafungin-treated and untreated mice was characterized to identify ascus-specific responses. During IR, similar numbers of trophic forms were present in the anidulafungin-treated and untreated mice; however, asci were only present in the untreated mice. IR resulted in a significant reduction of trophic forms from the lungs in both groups and asci in the untreated group. The presence of asci in untreated mice correlated with increased β-glucan content in the lungs. The untreated mice mounted immune responses associated with a deleterious host inflammatory response, including increased CD8(+) T cell influx and expression of macrophage inflammatory response markers. A more robust cellular response was also observed in the untreated mice, with increased numbers of macrophages and neutrophils that were associated with greater lung damage. Markers of a Th17 response were also elevated in the untreated mice. These results suggest that the host mounts unique responses to asci and trophic forms. That these 2 life cycle stages provoked distinct host response profiles has significant implications for clearance and interpretation of the host immune responses to PcP.

The biocontaminants and complexity of damp indoor spaces: more than what meets the eyes

Nine types of biocontaminants in damp indoor environments from microbial growth are discussed: (1) indicator molds; (2) Gram negative and positive bacteria; (3) microbial particulates; (4) mycotoxins; (5) volatile organic compounds, both microbial (MVOCs) and non-microbial (VOCs); (6) proteins; (7) galactomannans; (8) 1-3-β-D-glucans (glucans) and (9) lipopolysaccharides (LPS — endotoxins). When mold species exceed those outdoors contamination is deduced. Gram negative bacterial endotoxins, LPS in indoor environments, synergize with mycotoxins. The gram positive Bacillus species, Actinomycetes (Streptomyces, Nocardia and Mycobacterium), produce exotoxins. The Actinomycetes are associated with hypersensitivity pneumonitis, lung and invasive infections. Mycobacterial mycobacterium infections not from M. tuberculosis are increasing in immunocompetent individuals. In animal models, LPS enhance the toxicity of roridin A, satratoxins G and aflatoxin B1 to damage the olfactory epithelium, tract and bulbs (roridin A, satratoxin G) and liver (aflatoxin B1). Aflatoxin B1 and probably trichothecenes are transported along the olfactory tract to the temporal lobe. Co-cultured Streptomyces californicus and Stachybotrys chartarum produce a cytotoxin similar to doxorubicin and actinomycin D (chemotherapeutic agents). Trichothecenes, aflatoxins, gliotoxin and other mycotoxins are found in dust, bulk samples, air and ventilation systems of infested buildings. Macrocyclic trichothecenes are present in airborne particles <2 μm. Trichothecenes and stachylysin are present in the sera of individuals exposed to S. chartarum in contaminated indoor environments. Haemolysins are produced by S. chartarum, Memnoniella echinata and several species of Aspergillus and Penicillium. Galactomannans, glucans and LPS are upper and lower respiratory tract irritants. Gliotoxin, an immunosuppressive mycotoxin, was identified in the lung secretions and sera of cancer patients with aspergillosis produced by A. fumigatus, A. terreus, A. niger and A. flavus.

Elevated Levels of β-D-Glucan in Bronchoalveolar Lavage Fluid in Patients with Farmer’s Lung in Miyazaki, Japan

BACKGROUND

Farmers may be often exposed to beta-D-glucan in moldy hay, since straw for feed can be stored throughout the year.

OBJECTIVES

The aim of the present study was to clarify whether levels of beta-D-glucan, which modifies immune responses, are high in the respiratory tract in farmer's lung and whether beta-D-glucan participates in the pathogenesis of this condition.

METHODS

We measured beta-D-glucan levels in the bronchoalveolar lavage fluid (BALF) of 10 patients with farmer's lung, 4 with summer-type hypersensitivity pneumonitis (HP) and 10 healthy volunteers. Interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha levels in BALF were measured by enzyme-linked immunosorbent assay (ELISA). We investigated the effects of beta-D-glucan on nuclear factor (NF)-kappaB activation and on the release of IL-8 and TNF-alpha from small airway epithelial cells (SAECs) in vitro.

RESULTS

beta-D-Glucan levels in the BALF of farmer's lung patients were increased compared to those in patients with summer-type HP and in healthy volunteers. Additionally, IL-8 levels in BALF were higher in farmer's lung than in summer-type HP, and TNF-alpha levels were equal in the two patient groups but raised compared to those in healthy volunteers. High, but not low, concentrations of beta-D-glucan were found to induce NF-kappaB activation in SAECs. IL-8 levels in the supernatant obtained from SAEC cultures were increased following the addition of beta-D-glucan in vitro.

CONCLUSION

BALF from farmer's lung patients showed high beta-D-glucan levels, which may enhance the expression and release of cytokines through NF-kappaB activation in respiratory epithelial cells.

Eosinophilic pneumonias

Eosinophilic pneumonias (EP) encompass a wide spectrum of lung diseases characterized by peripheral blood eosinophilia (>1 x 10(9) eosinophils/l) and/or alveolar eosinophilia (>25%). Blood eosinophilia may be lacking, as in the early phase of idiopathic acute EP, or in patients already taking oral corticosteroids. EP may present with varying severity, ranging from almost asymptomatic infiltrates to the acute respiratory distress syndrome necessitating mechanical ventilation. Possible causes of EP must be thoroughly investigated, especially drugs and the variety of parasitic infections (considering history of travel or residence in areas of endemic parasitic infection). However, chronic EP remains idiopathic in many cases. When present, extrathoracic manifestations lead to suspect Churg-Strauss syndrome (CSS) or the hypereosinophilic syndrome (HES), the prognosis of which is dominated by cardiac involvement. Apart from the treatment of specific causes when possible, corticosteroids remain the cornerstone of symptomatic treatment for eosinophilic disorders, usually with a dramatic response, but frequent relapses when tapering or after stopping the treatment. The adjunction of immunosuppressants to corticosteroids is necessary in patients with CSS and poor prognosis factors. Imatinib has recently proven effective in the treatment of the myeloproliferative variant of the HES.

Eosinophilic interstitial lung disease

PURPOSE OF REVIEW

Although rare, the eosinophilic lung diseases are being increasingly identified as distinct clinical entities. These disorders are a heterogeneous group of disorders in which there is an increased number of eosinophils in the airways and/or lung parenchyma. These disease entities may be broadly separated into airway disorders (asthma, allergic bronchopulmonary mycosis, eosinophilic bronchitis, and bronchocentric granulomatosis) and parenchymal (interstitial) disorders. This review and update will concentrate on the latter group of entities.

RECENT FINDINGS

Recent publications in the field have concentrated on expanding the list of causative agents and clinical situations. An especially promising number of articles report advancements in the understanding of the pathogenetic mechanisms behind the development of the clinical syndromes.

SUMMARY

Whatever the function of the eosinophil in these disorders, it is important to remember that the disease processes lumped together as the eosinophilic lung diseases are a heterogeneous group of diseases. In an attempt to categorize these disorders, they have been connected, either appropriately or artificially, by their association with the eosinophil. Nevertheless, the eosinophilic connection may serve as a clue to pathogenesis and treatment.