[Treatment of hypereosinophilic syndromes of myeloproliferative expression with the combination of hydroxyurea and interferon alpha. Apropos of 7 cases].

Seven patients suffering from hypereosinophilic syndrome with clinical and/or hematological symptoms of a myeloproliferative syndrome were treated with a combination of hydroxyurea and interferon-alpha. To date, 6 of them have been followed for more than 1 year. In all cases, this therapy decreased circulating hypereosinophilia to under 1,500/mm3 and obtained normal eosinophil levels in 5 patients with a parallel regression of visceral complications. None of the patients experienced treatment-associated side effects, particularly hematological ones. Hypereosinophilic syndrome has a poor prognosis due, for the most part, to the development of visceral, cardiac and neurological complications, and, more secondarily, to the risk of progression towards acute leukemia. Conventional treatments, corticosteroids and hydroxyurea, have greatly improved the prognosis, but failure of these therapeutics remains common in the myeloproliferative form of the disease. Because interferon-alpha was proven to effectively treat chronic myeloid leukemia, it has been proposed for the treatment of hypereosinophilic syndromes, and encouraging results have been obtained despite the high daily doses required to control the disease. In the future, its association with hydroxyurea could represent an alternative therapy capable of controlling the disease at low doses thereby limiting the risk of side effects.