Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Sarcoidosis ?
    ### Response:
    What causes sarcoidosis? No one yet knows what causes sarcoidosis. It is thought by most scientists to be a disorder of the immune system, where the body's natural defense system malfunctions. Some physicians believe that sarcoidosis may result from a respiratory infection caused by a virus.
    