[A case of hypereosinophilic syndrome followed by bronchial asthma, intraventricular thrombus, and duodenitis].

We report a 43-year-old male with hypereosinophilic syndrome. The patient has had eosinophilia since the age of 25. He developed bronchial asthma at 41 years of age. In the following year, he consulted a gastroenterologist because of fever and abdominal discomfort. Upper gastrointestinal study showed duodenitis. At the age of 43 years, there was slight fever, watery diarrhea, and eosinophilia. Examination in our department disclosed hypereosinophilic syndrome associated with duodenitis, endomyocarditis with an intraventricular thrombus, and bronchial asthma caused by house dust. Both prednisolone and aspirin were administered with improvement of eosinophilia and partial thrombolysis. Assays of IL-3, GM-CSF, and IL-5 revealed increased activity of IL-5, GM-CSF, and IL-3 in this order. Especially IL-5 has by far the strongest activity in these cytokines. IL-5 may play an important role in the development of hypereosinophilic syndrome.