Interferon-α treatment of four patients with the Churg-Strauss syndrome

Background: Interferon-α is reported to have a beneficial effect on patients with the idiopathic hypereosinophilic syndrome. Objective: To study the effect of interferon-α on the Churg-Strauss syndrome. Design: Case series. Setting: University hospital. Patients: Four patients with biopsy- proven Churg-Strauss syndrome. Intervention: Interferon-α at dosages of 7.5 to 63 million U per week. Measurements: Disease extent, disease activity, and blood eosinophil count in a treatment period ranging from 14 to 25 months. Results: Interferon-α therapy led to remission of disease and a substantial reduction of the prednisolone requirement in two patients who had attained incomplete remission with cyclophosphamide or methotrexate. The third patient's condition stabilized, and the fourth patient maintained remission. During interferon-α therapy, the blood eosinophil count in all patients decreased in a dose-dependent manner and paralleled the extent of clinical disease and disease activity. Conclusions: Interferon-α may be an effective treatment for the Churg-Strauss syndrome. It seems to exert its effect primarily by producing a dose-dependent decrease in the blood eosinophil count.