Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Idiopathic acute eosinophilic pneumonia ?
    ### Response:
    Idiopathic acute eosinophilic pneumonia (IAEP) is characterized by the rapid accumulation of eosinophils in the lungs. Eosinophils are a type of white blood cell and are part of the immune system. IAEP can occur at any age but most commonly affects otherwise healthy individuals between 20 and 40 years of age.
    