Background: Interferon (IFN)-α is the only approved treatment for chronic hepatitis C. Interstitial pneumonia and, rarely, exacerbation of bronchial asthma have been reported as adverse pulmonary effects of IFN-α treatment. The purpose of the present study was to clarify whether IFN-α treatment affects pulmonary function and airway responsiveness in patients with chronic hepatitis C.
Methods: We studied 17 patients (nine males and eight females; mean age 46 years; range 30–62 years) with chronic active hepatitis C diagnosed by serum tests and liver biopsy. Pulmonary function tests included vital capacity (VC), forced expiratory volume in 1 s (FEV1), forced expiratory flow in the middle half of the forced vital capacity (FVC25–75%), total lung capacity and carbon monoxide diffusing capacity of the lung (DLCO), which was adjusted for hemoglobin concentration. Airway responsiveness was measured by methacholine inhalation challenge and determination of the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20). These tests were performed before and 3 months after initiation of IFN-α therapy.
Results: No patient developed interstitial pneumonia, although there was a tendency for the hemoglobin-adjusted DLCO to decrease. Other pulmonary function test parameters were not affected. Overall, there was no significant change in PC20 (from 15.0 to 11.4 mg/ mL). In three patients whose initial PC20 was within the normal range, airway hyperresponsiveness was induced and one patient developed bronchial asthma after IFN-α therapy.
Conclusions: These findings suggest that IFN-α induces airway hyperresponsiveness to methacholine in a few patients with chronic hepatitis C.