Reactive oxygen metabolite levels are surrogate biomarkers for predicting exacerbation of bronchial asthma

Background: Bronchial asthma (BA) is characterized by chronic airway inflammation. Although a majority of BA patients are controlled by standard treatment containing inhaled corticosteroids, some patients suffer acute exacerbation. Reactive oxygen species (ROS) such as hydrogen peroxide are generated by inflammatory cells which are involved in the pathogenesis of BA. However, the role of ROS levels as a biomarker in BA patients is not yet clear. Aims and objectives: We tried to determine the role of ROS levels as a biomarker in the clinical settings of BA. Methods: We enrolled patients with BA from 2013 through 2015 at the Department of Respiratory Medicine, Kyorin University Hospital. Pulmonary function tests, FeNO, serum reactive oxygen metabolite (ROM) levels and serum IL-6 and IL-8 were measured. Serum ROM levels were measured by d-ROMs test. Results: A total of 110 patients with BA were recruited. Serum ROM levels correlated with WBC (rs = 0.273, P = 0.004), neutrophil (rs = 0.235, P = 0.014), CRP (rs = 0.403, P P 1 (rs = -0.306, P = 0.001, rs = - 0.240, P = 0.012, respectively). Serum ROM levels were significantly higher in patients with severe exacerbation group than in patients without exacerbation group ( P = 0.025). Receiver-operating characteristics analysis showed that ROM levels associated with the occurrence of severe exacerbation (area under the curve: 0.699, 95% CI: 0.597 to 0.801, P = 0.025). Conclusions: ROM levels might reflect neutrophilic inflammation, and correlated with airway obstruction. This biomarker may be useful for predicting severe exacerbations of BA.