Thyroxine-induced production of superoxide anion by human alveolar neutrophils and macrophages: a possible mechanism for the exacerbation of bronchial asthma with the development of hyperthyroidism.

Bronchial asthma worsens after the development of hyperthyroidism. However, the biochemical mechanism of this phenomenon, which is induced by thyroxine (T4), remains obscure. In the present study, we showed that T4 directly stimulates production of superoxide anion by alveolar neutrophils and macrophages. These cells, when sensitized with a patient's serum and then treated with both the patient's specific allergen and T4, produced higher amounts of superoxide anion than did sensitized cells treated with the specific allergen or T4 alone. Our data suggest that T4 enhances production of reactive oxygen species by alveolar neutrophils and macrophages, which might play an important role in the exacerbation of bronchial asthma with the development of hyperthyroidism.