Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Large granular lymphocyte leukemia ?
    ### Response:
    Large granular lymphocyte (LGL) leukemia is a rare cancer of a type of white blood cells called lymphocytes. LGL leukemia causes a slow increase in white blood cells called T lymphocytes, or T cells, which originate in the lymph system and bone marrow and help to fight infection.
    