Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) IRAK-4 deficiency ?
    ### Response:
    IRAK-4 deficiency is an inherited disorder of the immune system (primary immunodeficiency). This immunodeficiency leads to recurrent infections by a subset of bacteria known as pyogenic bacteria but not by other infectious agents. (Infection with pyogenic bacteria causes the production of pus.
    