Interferon therapy induces the improvement of lung function by inhaled corticosteroid therapy in asthmatic patients with chronic hepatitis C virus infection: a preliminary study.

STUDY OBJECTIVES Several reports have suggested that subsets of asthmatic patients with chronic viral infection fail to respond to corticosteroid therapy. Therefore, this study was designed to determine that asthmatic patients with chronic hepatitis C virus (HCV) infection fail to improve lung function by inhaled corticosteroid therapy, and that interferon (IFN) therapy against HCV is effective for such patients. DESIGN Prospective observational study. SETTING University hospital. PATIENTS Forty asthmatic patients with chronic HCV infection. INTERVENTIONS After a 4-week run-in period, all asthmatic patients received therapy with inhaled beclomethasone dipropionate (BDP), 400 micro g twice daily for 6 weeks. After the first study, all asthmatic patients continued to receive inhaled BDP, and 30 HCV-positive asthmatic patients received IFN-alpha therapy for 6 months. MEASUREMENTS AND RESULTS Prebronchodilator and postbronchodilator FEV(1) values were examined after a 4-week run-in period, after 6 weeks of BDP therapy, and at 1 year from the end of IFN therapy. After a 4-week run-in period as well as after 6 weeks of BDP therapy, there were no significant differences in either prebronchodilator or postbronchodilator FEV(1) values among the three groups. However, 1 year after the end of IFN therapy, the mean prebronchodilator and postbronchodilator FEV(1) values were significantly higher in the IFN responder group (n = 11) [prebronchodilator FEV(1), 1.93 L (SD, 0.13 L); postbronchodilator FEV(1), 2.28 L (SD, 0.15 L)] than in the IFN nontreatment group (n = 10) [prebronchodilator FEV(1), 1.78 L (SD, 0.10 L); p = 0.01; postbronchodilator FEV(1), 2.07 L (0.13 L); p = 0.005] or the IFN nonresponder groups (n = 19) [prebronchodilator FEV(1), 1.79 L (SD, 0.15 L); p = 0.006; postbronchodilator FEV(1), 2.07 L (SD, 0.18 L); p = 0.002]. Moreover, prebronchodilator and postbronchodilator FEV(1) values were significantly higher only in the IFN responder group at 1 year after the end of IFN therapy than after the 4-week run-in period (prebronchodilator FEV(1), p = 0.028; postbronchodilator FEV(1); p = 0.002) or after 6 weeks of BDP therapy (p = 0.016 and p = 0.004, respectively). CONCLUSIONS Our findings suggest that chronic HCV infection in asthmatic patients is associated with impaired responses to inhaled BDP therapy and that intervention with IFN reverses such responses only in the IFN responder group.