A rare AIDS like autoimmune disease that causes a person to produce antibodies that attack his or her own immune system. The human body regularly makes molecules and proteins to tell different immune cells when to turn on and when to start fighting infections. In people infected with the adult-onset immunodeficiency syndrome, a special antibody blocks the normal function of one such molecule called interferon-gamma. Without functioning interferon-gamma, people become more susceptible to opportunistic infections similar to HIV/AIDS.

Unlike AIDS, adult-onset immunodeficiency syndrome is not a virus. The exact reason why the body makes such an antibody is unknown.