Bronchoalveolar lavage findings

This may help in discriminating the various causes of a diffuse pulmonary infiltrate seen on chest radiograph:

• increased T4 helper cells in sarcoidosis
• increased T8 suppressor cells in extrinsic allergic alveolitis, talc-induced lung disease and AIDS
  
  
• characteristic histiocyte X cells with positive staining for OKT6 monoclonal antibodies in Langerhan's histiocytosis
  
  
• neutrophilia is characteristic of:
  • smokers
  • fibrosing alveolitis
  • pneumoconiosis
    
    
• eosinophilia is characteristic of:
  • eosinophilic pneumonia
  • drug-induced lung disease