[Exogenous allergic alveolitis during childhood (author's transl)]

Four children aged 31/2 to 13 years, who developed allergic alveolitis as a result of antigenic exposure in a domestic situation are described. The clinical symptoms consisted of gradual onset of increasing dyspnoea, chronic cough and weight loss. Lung function tests showed characteristic reduction in vital and diffusion capacity. Serologically, antibodies against animal antigens were demonstrated in all patients. Radiologically there were pronounced reticular changes in both lungs affecting mostly the middle and lower zones. Occasionally there were miliary and sometimes confluent shadows. In differential diagnosis, virus infections, pneumocystis carinii, fungus infections, dermatomyositis, sarcoidosis and tuberculosis had to be considered. Apart from a short course of steroid treatment, it is necessary to make certain that the children are no longer exposed to the causal antigen. Under these conditions the prognosis is good, but otherwise the disease, as in adults who are continuously exposed to the antigen, results in pulmonary fibrosis.

Bronchopulmonary macrophage activation in the pathogenesis of hypersensitivity pneumonitis

Repeated intratracheal (IT) inoculation of rabbits with a homogenized, saline suspension of Micropolspora faeni produced bronchopulmonary (BP) histologic lesions resembling those of human hypersensitivity pneumonitis. With an in vitro phagocytic and bactericidal assay, an analysis of BP macrophages from M. faeni-injected rabbits demonstrated activation at both 2 and 4 weeks after the initiation of immunization. No BP macrophage activation was observed in immunized rabbits 6 weeks post-inoculation. BP macrophage activation was capable of recall after 6 weeks in M. faeni-sensitized animals that received a booster IT injection (2 mg) that did not activate "normal" alveolar wash cells. This recall of BP macrophage activation was accompanied by both a marked migration of mononuclear cells into the lung and positive delayed hypersensitivity skin reactions after intradermal injection of M. faeni antigen. Pulmonary histologic examination of sensitized, boosted rabbits suggested an enhanced cellular parenchymal infiltrate when compared with appropriate controls. The above observations confirm the occurrence of immunologically activated BP macrophages in rabbits inoculated witn M. faeni via the respiratory tract route and suggest a correlation between macrophage activation and histopathology.

Allergic alveolitis caused by home humidifiers. Unusual clinical features and electron microscopic findings

Allergic alveolitis (hypersensitivity pneumonitis) developed in two patients who were exposed to home humidifiers contaminated by thermophilic actinomycetes. Diagnosis was difficult because severe dyspnea was chronic and not easily associated with specific environmental exposure. Furthermore, chest roentgenograms were normal for long periods despite severe physiologic abnormalities. After several years of disabling symptoms, open lung biopsy findings suggested allergic alveolitis rather than sarcoidosis because a mononuclear interstitial infiltrate overshadowed the granulomas. Also, plasma cells were prominent and there was an intense bronchiolitis. Cultures of the humidifier water grew thermophilic organisms to which the patient's sera formed precipitins. Both patients experienced notable subjective and objective improvement following removal of the contaminated appliances. The ultrastructure of alveolar macrophages and basement membranes was similar to that described in animal models, suggesting cell-mediated hypersensitivity in the patients.

Production of thermophilic actinomycete-hay aerosols for use in experimental hypersensitivity pneumonitis

An investigation of the factors that influence the production of dense aerosols of Micropolyspora faeni and Thermoactinomyces vulgaris from hay cultures revealed that the density, freshness, and moisture content of the hay were important influences. Dry aerosols were produced under optimum conditions from hay cultures of either actinomycete and from sterile hay for inhalation challenges to unimmunized rabbits. Depressions in arterial oxygen tensions and hemolytic complement were monitored after such challenge. This investigation showed that hay cultures are capable of inciting a hypersensitivity-like reaction in the lungs, even in the absence of immunization to the organisms contained within the hay, but the entire hypersensitivity reaction cannot be attributed to M. faeni and T. vulgaris alone. Hay itself or other microbial or chemical components appear to have some heat-stable component that possibly contributes to the pathogenesis of the disease.

Fungal antigens as a source of sensitization and respiratory disease in Scottish maltworkers

Mycological and serological studies were carried out as part of a survey of respiratory disease in Scottish maltworkers. 70% of stained sputum smears from 574 workers showed the presence of higher plant cells and/or myclelia, and the spores of common environmental fungi. Penicillium spp. (90%), Rhizopus stolonifer (48%) and yeasts (53%) were the dominant fungi in 699 sputum cultures, and showed a similar proportional distribution in 327 samples of grain, malt, culms and dusts from fifty-six maltings. 57% of 711 men were serologically positive for fungi, 22% for Aspergillus fumigatus, 20% for A. clavatus, 10% for A. niger, 16% for Cladosporium herbarum and over 3% for Rhizopus stolonifer, 6% of 132 men were positive for Penicillium cyclopium. No precipitating antibodies to antigens from Alternaria tenuis, Aureobasidium pullulans, Candida albicans, Geotrichum candidum, Rhodotorula glutinis or Trichoderma viride were detected in tests of forty sera. Sera from the 5.2% of men with symptoms of extrinsic allergic alveolitis showed increased reactivity to mycelial antigens from Aspergillus clavatus. The fungus was cultured from 21% of maltings, 7% of all environmental samples and from the sputa of 8% of maltworkers.

Immunopatholgenesis of hypersensitivity pneumonitis

This review describes antigenic and host factors of possible significance in the immunopathogenesis of hypersensitivity pneumonitis (HP). Although certain immunologic studies suggest immune complex mechanisms in HP, recent experimental and clinical data accumulated support a role for cell-mediated immunity. In addition, some data support roles for anaphylactic and cytotoxic antibody-mediated reactivity as well. One type of reactivity alone may not be sufficient for production of HP, and local pulmonary immune responses may be most relevant to the pathogensis. Whether immune damage will be produced in an exposed individual or not may depend on the characteristics of the antigenic exposure as well as inherited and acquired individual differences in immunologic reactivity and possibly target organ sensitivity.

Extrinsic allergic alveolitis and contaminated cooling-water in a factory machine

Symptoms and signs typical of extrinsic allergic alveolitis occurred in 24 workers in a stationery factory. The illness was caused by inhalation of a water aerosol contaminated by microorganisms, and although no specific organism has been incriminated, affected workers had serum precipitins to the contaminated water, and the illness could be reproduced by inhalation challenge tests.

[Roentgenographic pattern of interstitial pneumonia and allergic alveolitis (author's transl)]

Roentgenographic examination of the lungs permits diagnosis of inflammatory and allergic pulmonary disease with predominantly interstitial and less alveolar involvement in which pulmonary fibrosis may develop. Reaction of the sensitised lung to allergic exposure causes typical roentgenological patterns. Development of pulmonary fibrosis in interstitial lung disease can be prevented be early cortison therapy.

Sauna-takers disease. Hypersensitivity pneumonitis due to contaminated water in a home sauna

Daily saunas taken by a young man were followed by fever, chills, malaise, dyspnea, cough, and myalgia from six to eight hours later. Symptoms, which were related to pouring water from a sauna bucket over the heating element, progressed to chronic dyspnea and fatigue. Serial serum samples showed precipitin reactions to bucket water and extracts of bucket mold. IgG antibody activity, demonstrated by radioimmunoassay, suggested that Pullularia was a major antigen.

Chronic hypersensitivity lung disease with recurrent episodes of hypersensitivity pneumonitis due to a contaminated central humidifer

A child with a 4-year history of acute and chronic respiratory symptoms of unknown aetiology was investigated for hypersensitivity pneumonitis. Lung disease due to inhalation of material from a contaminated central humidifier was suggested by the clinical history, the presence of precipitating antibodies in the serum against the humidifier water, a pulmonary response to challenge with the humidifier water, and marked improvement after removal of the humidifier. No fungi were cultured from the humidifier nor were antibodies against a number of fungal antigens identified by radioimmunoassay inhibition techniques. Antigenic material was found in the humidifier water and the household water prior to its reaching the humidifier. This antigenic material was not found in laboratory tap water supplied from the same general source (Lake Michigan) but from a different pumping station. Three of the child's siblings gave histories suggestive of a single concurrent episode of acute hypersensitivity pneumonitis and one sibling had a history suggestive of chronic hypersensitivity lung disease. No association could be found between HLA-haplotypy and disease in the patient and the siblings.