n. deficiency in the *immune response. This can be acquired, as in *AIDS, but there are many varieties of primary immunodeficiency occurring as inherited disorders characterized by *hypogammaglobulinaemia or defects in T-cell function, or both.
Impaired IMMUNITY resulting from inherited or acquired abnormalities of the immune system. This leads to increased vulnerability to infection. Important inherited examples of immunode?ciency are defects in function of GRANULOCYTES and the COMPLEMENT SYSTEM. Common acquired forms of immunode?ciency are defective function of B-type lymphocytes and hence antibody de?ciency in ‘common variable hypogammaglobulinaemia’, and grossly de?cient CD4 T-cell function – malfunctioning T-type lymphocytes – in AIDS, secondary to HIV infection (see AIDS/HIV).... immunodeficiency