Hypersensitivity pneumonitis induced by toluene diisocyanate: sequelae of continuous exposure.

A 41-year-old automobile paint sprayer showed the clinical features of hypersensitivity pneumonitis 1 week after he had begun to work with paint materials containing toluene diisocyanate. His symptoms began 6 to 8 hours after exposure to the agent and spontaneously disappeared by the next morning. He had diffuse, fine reticulonodular shadows on a chest roentgenogram and a restrictive impairment of pulmonary function. Immunoglobulin G antibody to toluene diisocyanate-human serum albumin was present in bronchoalveolar lavage fluid and sera: IgA antibody was present only in bronchoalveolar lavage fluid. Also, the patient had sensitized bronchoalveolar lymphocytes to toluene diisocyanate-human serum albumin. The histologic findings suggested hypersensitivity pneumonitis. The results of bronchoalveolar lavage, which was repeated on four separate occasions, showed lymphocytosis and a predominance of suppressor-cytotoxic T cells. The findings from serial determinations of humoral antibodies showed no changes consistent with the results of clinical and laboratory studies. In contrast, blastogenic responses of bronchoalveolar lymphocytes to toluene diisocyanate markedly decreased, and the patient showed clinical improvement despite continued exposure to the agent.