Bronchoalveolar lavage in liquid paraffin pneumonitis.

We evaluated cells and lipids recovered in the bronchoalveolar lavage fluid from seven patients with liquid paraffin pneumonitis. For each patient, the BALF was whitish with oil droplets on the surface. Alveolar macrophages contained numerous, large vacuoles that did not react with May-Grunwald-Giemsa, Papanicolaou, or periodic acid-Schiff but were stained in black with Sudan B, orange with Sudan III and red with oil Red O. Liquid paraffin was identified on thin layer chromatography of BALF-extracted lipids as a very hydrophobic compound migrating on the solvent front as control liquid paraffin. This abnormal spot was definitely identified as liquid paraffin by infrared spectroscopy and gas liquid chromatography for the first patient. The number and percentage of AMs were largely decreased in the BALF of each patient, whereas the number of neutrophils, eosinophils and lymphocytes was increased. These findings suggest that this cell-mediated inflammatory response plays a role in the development of interstitial fibrosis at late stages of liquid paraffin pneumonitis.