Objectives: The clinical features, airway histology, and detection of hexamethylene diisocyanate (HDI) protein adducts in endobronchial biopsies from a patient with HDI asthma are described.
Methods: Isocyanate asthma was diagnosed by history, methacholine challenge, and workplace HDI challenge. Bronchoscopy was performed 24 h after challenge and immunohistochemical staining was performed.
Results: Airway biopsies obtained at bronchoscopy demonstrated inflammatory changes typical for asthma, including increased airway eosinophils and T cells. Immunohistochemical staining with specific anti-HDI antibodies demonstrated the presence and localization of HDI adducts in human bronchial biopsies.
Conclusions: These studies confirm epithelial exposure to HDI following workplace challenge and demonstrate the feasibility of detecting and localizing isocyanate adducts in human lung tissue. Identifying and characterizing the airway macromolecules to which isocyanates bind in vivo are probably crucial to the understanding of how isocyanates cause sensitization and asthma. The ability to detect isocyanate adducts may also help characterize isocyanate exposure patterns and exposure-disease relationships.