Increased Pulmonary Gamma Interferon Production in Asbestosis

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Abstract
In order to determine if disordered cellular immune processes are present in the lungs of persons with asbestosis, we performed bronchoalveolar lavage (BAL) on 26 patients with either crocidolite- or chrysotile-induced pulmonary asbestosis and measured the spontaneous release of gamma interferon (IFN.gamma.), a marker of increased cellular immune activity. For comparison, 18 control subjects and 7 patients with active pulmonary sarcoidosis were also studied. Recovered BAL cells were cultured for 24 h (5 .times. 106/ml), and the supernatant was assayed for interferon by determining inhibition of cytopathic effect on encephalomyocarditis virus-induced lysis of WISH cells and characterized by monoclonal anti-IFN.gamma. antibody inhibition. Nine (35%) patients with asbestosis released increased amounts of IFN.gamma., up to 320 units/ml, the levels seen in the sarcoidosis patients. All control subjects released .ltoreq. 10 units/ml. All interferon released was IFN.gamma.. In asbestosis patients, IFN.gamma. production was not related to a history of cigarette smoking, there was no significant difference in the ratio of helper/inducer (Leu-3) to suppressor/cytotoxic (Leu-2) cells in IFN.gamma. producers compared to non-IFN.gamma. producers (p > 0.05), and IFN.gamma. production correlated significantly with serum IgG levels (p < 0.001) but not with the levels of IgM, IgA, antinuclear factor, or rheumatoid factor. These data suggest that active cellular immune processes are present in the lungs of a proportion of patients with asbestosis.