[Recent findings on occupational allergic alveolitis]

Occupational allergic alveolitis may be observed in agricultural or industrial environment. The presence of serum precipitins to specific antigens remains a valuable symptom. But other immunologic tests, such as inhibition of leucocyte migration, may be performed in doubtful cases or for retrospective diagnosis. It shows the role of delayed hypersensitivity in the pathogenesis of the disease. The functional investigation confirms the alveolar involvement but also reveals in some cases (by flow/volume curves and compliance tests) evidence of small airways disease. The broncho-alveolar lavages show the high percentage of lymphocytes (mainly T lymphocytes) in in the cell population recovered and a very typical phospholipid profile in the supernatant (total absence of lecithin whereas the two other fractions phosphatidyl-inositol and phosphatidyl-ethanolamine are considerably enhanced). The tensioactive properties of the phospholipids were investigated by fluorescence polarisation technique. High values of microviscosity were found in patients. These findings provide a new diagnostic guidance and a new therapeutic approach of these diseases.