Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Immune Thrombocytopenia ?
    ### Response:
    In most cases, an autoimmune response is thought to cause immune thrombocytopenia (ITP).
                
Normally, your immune system helps your body fight off infections and diseases. In ITP, however, your immune system attacks and destroys your body's platelets by mistake.
    