Occupational rhinitis and bronchial asthma due to TBTU and HBTU sensitization

Exposure to an increasing amount of products in the work environment is leading to new cases of occupational asthma among workers. We report the case of a worker at a pharmaceutical plant who developed occupational rhinitis and bronchial asthma due to HBTU: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate and TBTU: 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate sensitization, two chemical products widely used in peptide synthesis and coupling. Skin tests (prick test) with HBTU and TBTU solutions in PBS were positive at a concentration of 1 mg/ml. Skin tests with the same solutions in 10 atopic controls yielded a negative result. Nasal challenge tests with these products were positive with HBTU at a concentration of 0.01 mg/ml and TBTU at a concentration of 1 mg/ml. In both cases PNIF (peak nasal inspiratory flow) decreased by more than 60% and severe sneezing and rhinorrhea were induced. Nasal challenge tests performed on 10 atopic controls with TBTU and HBTU at a concentration of 1 mg/ml were negative. We conclude that the patient presents occupational rhinitis and bronchial asthma due to TBTU and HBTU; the operational mechanism is probably immunological IgE-mediated given the positive prick tests and nasal challenge with these products.