Interferon treatment of refractory idiopathic thrombocytopenic purpura (ITP).

Up to 30% of patients with idiopathic thrombocytopenic purpura (ITP) are refractory to standard therapy with corticosteroids and splenectomy. The treatment of refractory ITP is barely effective, but promising results of interferon therapy were reported recently. In a prospective study 21 refractory ITP patients were treated with interferon alpha 2B at 3 million Units three times a week for a period of 4 weeks. Ten out of 21 patients had a response, of whom 2 had a complete response of 3.5 and 7 months duration, after which both relapsed. One other patient retreated after relapse has a complete response of 24+ months. The characteristics of the responding patients were not different from the non-responding patients. Adverse effects were minimal. Short treatment with interferon in refractory ITP patients may be justified and the results reported here challenge us to elucidate the mechanism of action of interferon.