Increased serum concentration of urinary trypsin inhibitor with asthma exacerbation

The aim of the study was to determine whether the amount of urinary trypsin inhibitor (UTI) in serum, a degenerate induced by neutrophil elastase (NE), reflects the degree of bronchial inflammation in children with acute asthma exacerbation. The involvement of neutrophil-mediated inflammation plays as important a role as eosinophil-mediated inflammation in the pathogenesis of acute asthma exacerbation. However, no measurable marker is sensitive enough to assess neutrophil-mediated inflammation in the airways. The pre-alpha-/inter-alpha-trypsin inhibitors are assumed to be precursors of UTI. NE degrades pre-alpha-/inter-alpha-trypsin inhibitors to liberate UTI. UTI concentrations in 25 childhood patients admitted with asthma exacerbation and 15 control subjects were measured by means of one-step sandwich-type enzyme immunoassay. Serum UTI concentrations in the patients at admission were significantly higher than control values (10.597+/-0.649 and 6.136+/-0.303 U x mL(-1), respectively (mean+/-SEM)). These levels returned to baseline values with improvement in the asthmatic symptoms. However, serum NE and alpha1 antitrypsin concentrations were not significantly different between patients and controls, even during acute exacerbation in the former. The findings suggest that neutrophil-mediated inflammatory events are involved in exacerbation of childhood asthma. The monitoring of urinary trypsin inhibitor concentrations might be useful for evaluating the neutrophil-mediated inflammation in childhood asthma attack.