Extrinsic allergic alveolitis after Aspergillus fumigatus inhalation. Evidence of a type IV immunologic pathogenesis

Fungal and bacterial species on biowaste workers' hands and inhalation zone, and potential airway deposition

This study aims to investigate the microbiological working environment of biowaste workers, focusing on airborne fungal and bacterial species exposure, size distribution, and species on workers' hands. The research, conducted across six plants with 45 personal exposure assessments, revealed a total of 150 bacterial species and 47 fungal species on workers' hands, including 19 and 9 species classified in risk class 2 (RC2), respectively. Workers' exposure analysis identified 172 bacterial and 32 fungal species, with several in RC2. In work areas, 55 anaerobic bacterial species belonging to RC2 were found. Different species compositions were observed in various particle size fractions, with the highest species richness for anaerobic bacteria in the fraction potentially depositing in the secondary bronchi and for fungi in the pharynx fraction. The geometric mean aerodynamic diameter (DG) of RC2 anaerobic bacteria was 3.9 µm, <1.6 µm for Streptomyces, 3.4 µm for Aspergillus, and 2.0 µm for Penicillium. Overlapping species were identified on workers' hands, in their exposure, and in work areas, with Bacillus amyloliquefaciens, Leuconostoc mesenteroides, Bacillus cereus, Enterococcus casseliflavus, and Aspergillus niger consistently present. While the majority of RC2 bacterial species lacked documented associations with occupational health problems, certain bacteria and fungi, including Bacillus cereus, Escherichia coli, Enterobacter, Klebsiella pneumonia, Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Lichtheimia corymbifera, Lichtheimia ramosa, and Paecilomyces variotii, have previously been linked to occupational health issues. In conclusion, biowaste workers were exposed to a wide range of microorganisms including RC2 species which would deposit in different parts of the airways.

Acute eosinophilic pneumonia caused by composter vapor inhalation: A case report

A 65-year-old woman presented to a local hospital with a 4-day history of cough, fever, and dyspnea. She had started using a composter and had been exposed to the vapor for 18 days before her first visit. She was diagnosed with acute eosinophilic pneumonia (AEP) based on her symptoms, the presence of bilateral pulmonary opacities on computed tomography, and alveolar eosinophilia confirmed by bronchoalveolar lavage. Inhalation of the composter vapor was thought to be the cause of AEP. Aspergillus fumigatus was cultured from the composter soil and the bronchoalveolar lavage fluid. She fully recovered without systemic corticosteroid administration by avoiding the composter.

Assessment of the total inflammatory potential of bioaerosols by using a granulocyte assay

Occupational health symptoms related to bioaerosol exposure have been observed in a variety of working environments. Bioaerosols contain microorganisms and microbial components. The aim of this study was to estimate the total inflammatory potential (TIP) of bioaerosols using an in vitro assay based on granulocyte-like cells. A total of 129 bioaerosol samples were collected in the breathing zone of workers during their daily working routine at 22 biofuel plants. The samples were analyzed by traditional assays for dust, endotoxin, fungal spores, (1-->3)-beta-d-glucan, total number of bacteria, the enzyme N-acetyl-beta-d-glucosaminidase (NAGase; primarily originating from fungi), Aspergillus fumigatus, and mesophilic and thermophilic actinomycetes; the samples were also assayed for TIP. In a multilinear regression four factors were significant for the TIP values obtained: endotoxin (P < 0.0001), fungal spores (P < 0.0001), (1-->3)-beta-d-glucan (P = 0.0005), and mesophilic actinomycetes (P = 0.0063). Using this model to estimate TIP values on the basis of microbial composition, the correlation to the measured values was r = 0.91. When TIP values obtained in the granulocyte assay were related to the primary working area, we found that bioaerosol samples from personnel working in straw storage facilities showed high TIP values ( approximately 50 times the TIP of unstimulated controls). In contrast, bioaerosol samples from personnel with work functions in offices or laboratories showed low TIP values ( approximately 5 times the TIP of the unstimulated control). This indicates, as expected, that these areas were less contaminated. In conclusion, the granulocyte assay reacts to multiple contaminants in the environmental samples and can be used to obtain a measurement of TIP. Therefore, potential occupational health effects related to inflammation of the airways in a working environment can be estimated using this assay.

Respiratory syncytial virus replication is prolonged by a concomitant allergic response

Epidemiological studies show an association between early exposure to respiratory syncytial virus (RSV) and the development or exacerbation of asthma. This idea is supported by studies in mice that demonstrate worsened airway hyper-reactivity (AHR) when RSV-infected animals are exposed to allergen. The effect of allergen on RSV disease, however, has not been reported. Cotton rats (Sigmodon hispidus) that have been used as a model to study RSV pathogenesis were sensitized to extracts of Aspergillus fumigatus (Af), a common household mould. The allergic response to Af included eosinophilia, formation of granulomas and induction of Th2 type cytokines. RSV infection prior to allergen challenge resulted in exacerbation of the inflammatory response as well as increased airway responsiveness to methacholine. The exacerbated response was indeed dependent on virus replication. Virus replication in turn was influenced by the allergic response, with persistence in the noses for 2 days longer in animals challenged with allergen. This diminished clearance corresponded to decreased induction of mRNA for IFN-gamma, a Th1-type cytokine that is characteristic of viral infection. Treatment of RSV-infected Af-challenged animals with recombinant IFN-gamma reduced the allergic inflammatory response as well as the relative levels of Th1 and Th2 cytokine mRNA. However, this treatment did not reduce airway reactivity, showing that these pathologic and physiologic measures of exacerbated disease are independent. We speculate that the reciprocal effect of the allergic response on viral immunity may benefit the host by limiting exacerbation of physiologic responses that are IFN-gamma-dependent.

Clinical use of immunoassays in assessing exposure to fungi and potential health effects related to fungal exposure

OBJECTIVE

To review and summarize current evidence regarding the proper role of immunoassays in clinical assessments of exposure to fungi and health effects related to fungal exposure.

DATA SOURCES

We reviewed relevant scientific investigations and previously published reviews concerning this topic.

STUDY SELECTION

The authors' clinical, laboratory, and public health experiences were used to evaluate relevant data for scientific merit.

RESULTS

Testing to determine the presence of IgE to specific fungi may be a useful component of a complete clinical evaluation in the diagnosis of illnesses that can be caused by immediate hypersensitivity such as allergic rhinitis and asthma. Detection of IgG to specific fungi has been used as a marker of exposure to agents that may cause illnesses such as hypersensitivity pneumonitis. However, the ubiquitous nature of many fungi and the lack of specificity of fungal antigens limit the usefulness of these types of tests in the evaluation of potential building-related illness and fungal exposure. Specific serologic tests (such as tests for cryptococcal antigen, coccidioidal antibody, and Histoplasma antigen) have been shown to be useful in the diagnosis of some fungal infections, but these are the exception not the rule.

CONCLUSIONS

There is currently not enough scientific evidence to support the routine clinical use of immunoassays as a primary means of assessing environmental fungal exposure or health effects related to fungal exposure. Health care providers who care for persons expressing concerns about the relationship of symptoms to potential exposure to fungi are advised to use immunoassay results with care and only as an adjunct to a comprehensive approach to patient care.

Semiinvasive pulmonary aspergillosis: CT and pathologic findings in six patients

OBJECTIVE

We describe the chest CT and pathologic findings of semiinvasive pulmonary aspergillosis in six patients.

CONCLUSION

Semiinvasive pulmonary aspergillosis should be considered in the mildly immunocompromised patient with CT findings that reveal persistent parenchymal abnormalities. Patterns include consolidation and mass.

The epidemiology and prevention of invasive aspergillosis

Over the past two decades, the incidence of invasive aspergillosis (IA) has risen inexorably. This is almost certainly the consequence of the more widespread use of aggressive cancer chemotherapy regimens, the expansion of organ transplant programmes and the advent of the acquired immunodeficiency syndrome (AIDS) epidemic. Despite the development of new approaches to therapy, IA still remains a life-threatening infection in immunocompromised patients and is the most important cause of fungal death in cancer patients. It is clear that the prevention of severe fungal infection by the use of effective infection control measure should be the priority of the teams involved in managing at-risk patients. The evidence from clinical and molecular epidemiological studies is reviewed and current thinking on sources and routes of transmission of the organism are discussed. Our increasing understanding of these has led to the development of a variety of environmental and general strategies for the prevention of IA. It is anticipated that these, coupled with the use of prophylactic antifungal agents active against Aspergillus spp., will have a significant impact upon the morbidity and mortality associated with this infection.

Fungus allergens inside and outside the residences of atopic and control children

Airborne fungi were collected during the peak fungus season, using the N6 Andersen sampler inside and outside the homes of 46 asthmatic children, 20 atopic children, and 26 nonatopic control children in the Taipei area. The geometric mean fungus concentrations of the asthmatic, atopic, and control groups were found to be 565, 411, and 608 colony-forming units (CFU) per m3 in the living rooms; 659, 464, and 602 CFU m3 in the bedrooms; and 547, 449, and 668 CFU m3 outdoors; respectively. Aspergillus, Cladosporium, and Penicillium were observed to be the most common microfungi, both indoors and outdoors. High correlations between indoor fungus levels (living rooms or bedrooms) and the corresponding outdoor levels were observed for these predominant genera. With regard to the Aspergillus species composition, A. flavus and A. niger were observed to be predominant and are, therefore, recommended to be included on a skin test panel. Moreover, among these three groups, there were statistically significant concentration differences for Cladosporium and Penicillium.

Hypersensitivity pneumonitis resulting from Aspergillus fumigatus in a greenhouse

A 57-y-old female who had cultivated vegetables in a plastic greenhouse developed a case of hypersensitivity pneumonitis from Aspergillus fumigatus. This report exemplifies a potential hazard caused by a thermotolerant fungus, A. fumigatus, in a poorly constructed greenhouse.

Fatal pulmonary aspergillosis presenting as acute eosinophilic pneumonia in a previously healthy child

A previously healthy boy presented with cough and diffuse pulmonary interstitial infiltrates. Acute eosinophilic pneumonia was diagnosed by bronchoalveolar lavage in the absence of a demonstrable infectious etiologic agent. Corticosteroid therapy resulted in immediate improvement but was followed by respiratory distress and death from invasive aspergillosis and Pseudomonas cepacia sepsis.

Hypersensitivity pneumonitis versus invasive pulmonary aspergillosis: two cases with unusual pathologic findings and review of the literature

Two brothers simultaneously exposed to moldy hay, who developed differing forms of Aspergillus-related lung disease, are presented. Patient 1 developed a true case of hypersensitivity lung disease, whereas his brother developed invasive aspergillosis with bronchoalveolar lavage eosinophilia and unusual pathologic features including tissue eosinophilia. The possible overlap between hypersensitivity pneumonitis and invasive aspergillosis in the immunocompetent host is discussed.

Pathogenetic and serological aspects of pulmonary aspergillosis

Af is an important pathogen of the bronchopulmonary system, and the clinical spectrum encompasses aspergilloma, CNPA, IPA, ABPA, bronchial asthma, and allergic alveolitis. Bronchial carriage may, however, not always be associated with pathological effects. The polymorphism of the aspergillus-related disorders seems mostly to depend upon the different responses of the hosts. This review considers the antigenic composition of Af and specific antibody responses in man in relation to the pathogenesis and diagnosis of the various forms of pulmonary aspergillosis. More than 200 macromolecular components have been listed for Af and more than 30 antigens found to react with human sera. Serum antibodies to Af are common in healthy subjects. Schønheyder and his associates (A-L) have shown that IgG, IgA and IgM antibodies in healthy subjects are directed towards antigens to which also patients with aspergillosis strongly react. With immunofluorescent staining these antigens were found to be associated with hyphal walls, and a MW 470,000 fraction from ruptured mycelium was most reactive in ELISA. The respiratory tract appears to be the major route for exposure since the humoral responses include IgA class antibodies, and sIgA antibodies are found in bronchial secretions. Moreover, IgG antibody levels to the MW 470,000 fraction correlate with occupational exposure and smoking habits. In patients with cystic fibrosis high IgG antibody levels to MW 470,000 and MW 25,000-50,000 antigen fractions were associated with the carriage of Af in the sputum. An individual patient's level of IgA antibodies to the MW 470,000 fraction was inversely related to the Af carrier rate, and this was also true for IgE dependent reactivity to Af antigens. These observations indicate that IgG antibodies to some antigens mirror the extent of antigenic exposure, whereas some IgA and IgE antibodies may play a protective role against bronchial colonization with Af. IgG antibody determinations by ELISA were found to provide a higher diagnostic efficacy in pulmonary aspergillosis than IgA antibody assays. With IgG antibodies there were statistically significant differences between patients and the controls and there was little overlap of ELISA values between the groups. The fractions of MW 250,000 with catalase activity and MW 25,000-50,000 with protease activity, were most suitable for serological diagnosis. A gel immunoelectrophoretic assay proved Af catalase to be a major diagnostic antigen in patients with aspergilloma or with an apical aspergillus lung infiltrate.(ABSTRACT TRUNCATED AT 400 WORDS)

The varying manifestations of Aspergillus lung disease

The fungus Aspergillus may cause a variety of pulmonary disorders as a result of its ability to act as an allergen, as a simple saprophyte or as an infectious organism. The clinical manifestations range from hypersensitivity syndromes, in which corticosteroid therapy may be indicated, to disseminated infections, in which corticosteroid agents may be causative. The diagnosis may not be immediately apparent. Six cases are presented to illustrate the sometimes confusing manifestations of the disease.

Significance of IgG antibodies against environmental microbial antigens in a farming population

A group of dairy farmers studied 6 years earlier in a field survey was re-surveyed for respiratory symptoms, occupational capability and the presence of antibodies against environmental micro-organisms. Specific IgG antibodies to Micropolyspora faeni, Thermoactinomyces vulgaris, Aspergillus umbrosus and Aspergillus fumigatus were measured by ELISA from the serum samples obtained in the two surveys. Antibody titres remained constant in 70% of both farmers and controls, but where changes took place, the titres against the actinomycete antigens tended to rise, whereas both increases and decreases were detected equally against the Aspergillus antigens. The titre of specific antibody to any of the four micro-organisms, when measured from a single serum specimen, seemed to be of little diagnostic value. Observed changes however, were more diagnostic, in that a fall in titre, especially against the Aspergillus antigens, was closely associated with a definite decrease in exposure, such as after retirement. Increased titres occurred in farmers with continued exposure, and those against the actinomycetes were associated with the appearance of symptoms in previously symptom-free individuals. In a case of farmer's lung which developed in this population during the follow-up period, significant increases were detectable against T. vulgaris and M. faeni.

Enzyme-linked immunosorbent assay in the detection of specific antibodies against Aspergillus in patient sera

A biotin-avidin linked enzyme immunoassay (BALISA) was used to detect Aspergillus fumigatus specific antibodies in the sera of patients with aspergillosis. Culture filtrate antigens from a strain of A. fumigatus grown in synthetic medium was used in the ELISA. This antigen was characterized by various immunochemical methods including isoelectric focusing, two-dimensional electrophoresis and antigen antibody crossed-immunoelectrophoresis. Sera from patients having allergic asthma, allergic bronchopulmonary aspergillosis (ABPA), aspergilloma and normal controls were studied. High levels of IgE and IgG antibodies specific to A. fumigatus antigens were detected in ABPA while only IgG antibodies were seen in aspergilloma. The normal group and the allergic asthma failed to show any differences in the specific antibody content. Biotin-avidin linked immunosorbent assay was found to be very useful in detecting both IgG and IgE antibodies, and by using characterized antigens reproducible and dependable results can be obtained.

Detection of antigens in lung biopsies by immunoperoxidase staining in extrinsic allergic bronchiolo-alveolitis (EABA)

Open lung biopsy specimens of 14 patients with extrinsic allergic bronchiolo-alveolitis (EABA) were studied by immunoperoxidase staining with avidin-biotin-complex method using nonconjugated antisera to Micropolyspora faeni, Thermoactinomyces vulgaris, Aspergillus fumigatus, and Aspergillus umbrosus. Antigenic intracellular material was found in macrophages and giant cells of granulomas in the lung tissue of 8 patients. This finding supports the hypothesis which suggests that macrophages and T-lymphocytes contribute to the tissue injury in EABA.

Immunohistochemical identification of Aspergillus fumigatus in farmer's lung

Fragments of fungi in a granuloma were demonstrated in lung biopsy specimens of two patients with farmer's lung by using an avidin-biotin-complex method with non-conjugated rabbit antiserum to Aspergillus fumigatus. Our findings suggest that the type IV or cell-mediated immunity at least partly explains the pathogenesis of farmer's lung.

Enzyme-linked immunosorbent assay (ELISA) for IgG antibodies in farmers' lung disease

The ELISA was used for detection of specific IgG antibodies to Micropolyspora faeni antigens in 158 farmers with a history of exposure to mouldy hay, eighty-eight of whom had a diagnosis of farmer's lung. The farmers' lung group had significantly higher values in the ELISA than both the seventy exposed but asymptomatic farmers (P less than 0.001) and a group of thirty-one adult controls (P less than 0.001). The asymptomatic farmers also had significantly higher values than the control group (P less than 0.02). The ELISA correlated better with the clinical diagnosis than the Ouchterlony agar-gel double-diffusion (precipitin) test. None of the control group gave positive reactions in the ELISA or the precipitin tests. The ELISA is therefore a sensitive, specific and quantitative test which is readily available and widely applicable.

A guide to the recent literature on aspergillosis as caused by Aspergillus fumigatus, a fungus frequently found in self-heating organic matter

Spores of Aspergillus fumigatus have been found to be abundantly present in the outdoor air at a site where large scale experimental composting of sewage sludge is in progress at Beltsville, Maryland. The health significance of this finding, for that site and for others in the future, is still only incompletely understood. Further studies are in progress to characterize absolute concentrations of the spores of the fungus in air at the site, spore dispersal by air from composting operations, and background environmental spore levels in air. The present paper contains a list of references to papers on health effects of A. fumigatus, many published in the past ten years, along with a review of the same designed to assist the reader in finding information on particular aspects of the subject in the literature. It is intended primarily as an aid to individuals interested in sludge composting and wishing to attain an insight into the A. fumigatus-composting situation, but it may also interest others concerned with other substrates which become moldy at 40--50 C. A. fumigatus has been found in great numbers in naturally and artificially heated environments such as decaying leaves, compost heaps, solar heated sloughs, cooling canals for nuclear power generators, silos, grain storage bins, boiler rooms, detritus around steam turbines and sauna baths. The evident practical merits of sludge composting have been described elsewhere; the information presented here has its main significance in respect to requirements for choice of locations for composting sites and to process and design criteria.

The diagnostic value of antibodies to the traditional antigens of farmer's lung in Finland

Precipitating antibodies towards antigens associated with farmer's lung disease were studied in Finnish dairy farming and non-farming rural populations and the results were compared to those of serum samples of patients suspected of having a fungal allergy. The antigen panel consisted of Aspergillus fumigatus, Micropolyspora faeni and Thermoactinomyces vulgaris. All three microbes seemed to be important environmental inducers of antibody formation. The prevalence of antibodies towards all of them was higher in the patient group. The presence of A. fumigatus and T. vulgaris antibodies correlated best with the occurrence of respiratory disease. The difference in M. faeni antibody prevalence between patients and the control group was less significant. The results suggest that in Finland the relative importance of those microorganisms associated with farmer's lung disease may be different from that reported from other countries.