Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) MyD88 deficiency ?
    ### Response:
    MyD88 deficiency is an inherited disorder of the immune system (primary immunodeficiency). This primary immunodeficiency affects the innate immune response, which is the body's early, nonspecific response to foreign invaders (pathogens). MyD88 deficiency leads to abnormally frequent and severe infections by a subset of bacteria known as pyogenic bacteria.
    