Interferons and their application in lung diseases.

We enjoyed the comprehensive review on the potential therapeutic applications of interferon (IFN) in pulmonary diseases by Antoniou and associates (January 2003).1 Here, we would like to extend the conditions responsive to IFN treatment to include the Churg-Strauss syndrome (CSS). The CSS is an uncommon type of eosinophilic granulomatous inflammation with associated vascular necrosis accompanied by marked eosinophilia, raised IgE serum concentrations, and usually severe corticosteroid-dependent perennial asthma.2 In 1997, we treated a 31-year-old woman with a histologically proven CSS resistant to first-line therapy. Administration of IFN(50 g) lead to a substantial clinical improvement allowing a low-dose steroid maintenance therapy.3 During the past 3 years, we have offered IFN treatment to four additional patients with histologically confirmed CSS who were either resistant to standard therapy (oral corticosteroid alone or in combination with immunosuppressants) or suffered from severe drug-related side effects (Table 1). The patients were treated with 9 g IFNcon (equivalent to 3 million units of IFN2b) administered subcutaneously thrice weekly. In all patients, IFNinduced a significant clinical improvement with respect to clinically relevant parameters of the disease (asthma, rhinitis, sinusitis, hypereosinophilia) with partial (patients BG and UG) and complete remissions (patients KV and BK). In patient KV, both the symptoms of the hemorrhagic cystitis and the Cushing syndrome (weight reduction of 19 kg) disappeared. Also, the peripheral polyneuropathia in patient KV continues to improve since initiation of therapy. The above improvements were achieved despite tapering of oral steroids in all patients. In two patients (patients KV and BK), corticoid treatment could be discontinued. Side effects occurring 2 to 12 h after injection included arthralgia, nausea, malaise, and fever, but were transient and decreased within 3 to 4 weeks. One patient (patient UG) acquired a hyperthyroidism 5 months after initiation of IFN therapy. Our data are supported by a total of six patients who have also responded to IFN. Tatsis et al4 studied the effect of IFN(7.5 to 63 million U/wk) on four patients with CSS. Treatment led to a remission of the disease in all patients and a substantial reduction of the prednisolone requirement in two patients who had attained incomplete remission with cyclophosphamide or methotrexate. In one patient, stabilization of the condition was achieved. Interestingly, another sustained remission was achieved after treatment for 1 year. Lesens et al5 reported a case of severe CSS resistant to standard treatment with mediastinal eosinophilic lymphadenopathy, which showed significant clinical improvement after IFN2b was initiated. A beneficial response to treatment with interferon2b was also observed in a patient with prominent skin involvement.6 Taken together, the data summarized above suggest that CSS may be another pulmonary disease entity responding to treatment with IFN.