Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Chronic active Epstein-Barr virus infection ?
    ### Response:
    Chronic active Epstein-Barr virus infection is a rare condition in which the body makes too many lymphocytes, a type of white blood cell. Lymphocytes are an important part of the immune system because they help fight off diseases and protect the body from infection.
    