Recurrent nocturnal asthma after exposure to grain dust.

Bronchial provocation tests performed on two seperate occasions in a farmer with dust from his own grain led to immediate and late respiratory reactions followed, without further exposure to grain dust, by severe respiratory reactions during subsequent nights. Studies of lung function, including measurements of closing volume, suggested that both large and small airways rather than lung parenchyma were primarily involved. Examination of the grain samples together with the results of skin and serologic tests suggested that the grain mite, Glycyphagus destructor, might be an important allergen. Serum concentrations of C3 and C4 did not alter during these recurrent nocturnal asthmatic reactions.