Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Multiple Sclerosis ?
    ### Response:
    An unpredictable disease of the central nervous system, multiple sclerosis (MS) can range from relatively benign to somewhat disabling to devastating, as communication between the brain and other parts of the body is disrupted. Many investigators believe MS to be an autoimmune disease -- one in which the body, through its immune system, launches a defensive attack against its own tissues.
    