Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Chronic Eosinophilic Leukemia ?
    ### Response:
    Key Points
                    - Chronic eosinophilic leukemia is a disease in which too many white blood cells (eosinophils) are made in the bone marrow.    - Signs and symptoms of chronic eosinophilic leukemia include fever and feeling very tired.
                

    