Hypersensitivity pneumonitis (extrinsic allergic alveolitis) induced by isocyanates.
BACKGROUND
Chemical-induced hypersensitivity pneumonitis has been so far rarely described. The purpose of this study was to find out whether hypersensitivity pneumonitis is a common disorder in isocyanate workers.


METHODS
Company physicians' case histories of 1780 isocyanate workers were evaluated. In 16 subjects suspected of having isocyanate-induced hypersensitivity pneumonitis, chest x-ray films were made; levels of IgE and IgG antibodies to isocyanate-human serum albumin were estimated; conjugates and isocyanate challenge tests, bronchoalveolar lavage fluid analyses, and/or lung histologic investigations were performed.


RESULTS
Each of the 14 study patients who had hypersensitivity pneumonitis had work-related dyspnea and fever occurring several hours after the start of work with isocyanates. Typical clinical findings were the reduction of lung diffusing capacity (n = 10), reticular or nodular lung patterns in the x-ray film (n = 9), and serum IgG antibodies specific to isocyanate-human serum albumin conjugates (n = 10). Restrictive ventilation patterns in the inhalation challenge tests (n = 5), lymphocytic and/or neutrophilic alveolitis seen in bronchoalveolar lavage fluid analyses (n = 7), and lymphohistiocytic patterns mostly associated with mild fibrosis in lung histology (n = 5) confirmed the diagnosis.


CONCLUSIONS
Occupational exposure to isocyanate vapors and aerosols induces typical hypersensitivity pneumonitis in at least 1% of the isocyanate workers with symptoms. Diphenylmethane diisocyanate was found to be the main cause of this disorder.
Baur
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Professional Associations' Research Institute for Occupational Medicine, Ruhr University, Bochum, Germany.
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects* / Q000276:immunology; D000542:Alveolitis, Extrinsic Allergic / Q000209:etiology*; D000918:Antibody Specificity; D001706:Biopsy; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D001999:Bronchoscopy; D002617:Chemical Industry; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D017953:Isocyanates / Q000009:adverse effects* / Q000276:immunology; D008168:Lung / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D013902:Radiography, Thoracic; D015656:Respiratory Mechanics; D001559:Benzhydryl Compounds
D000485:Allergens; D007074:Immunoglobulin G; D017953:Isocyanates; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds