Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to common variable immune deficiency ?
    ### Response:
    CVID is believed to result from mutations in genes that are involved in the development and function of immune system cells called B cells. B cells are specialized white blood cells that help protect the body against infection. When B cells mature, they produce special proteins called antibodies (also known as immunoglobulins).
    