| Noun | 1. | immunodeficiency - immunological disorder in which some part of the body's immune system is inadequate and resistance to infectious diseases is reduced immunological disorder - a disorder of the immune system acquired immune deficiency syndrome, AIDS - a serious (often fatal) disease of the immune system transmitted through blood products especially by sexual contact or contaminated needles agammaglobulinemia - a rare immunological disorder characterized by the virtual absence of gamma globulin in the blood and consequent susceptibility to infection hypogammaglobulinemia - an abnormally low concentration of gamma globulin in the blood and increased risk of infection SCID, severe combined immunodeficiency, severe combined immunodeficiency disease - a congenital disease affecting T cells that can result from a mutation in any one of several different genes; children with it are susceptible to infectious disease; if untreated it is lethal within the first year or two of life immunocompetence - the ability to develop an immune response following exposure to an antigen |