immune disorders
Selective Immunoglobulin Deficiency
Introduction
Selective immunoglobulin deficiency is usually inherited. It results in a low level of one type (class) of antibody (immunoglobulin), even though the levels of other immunoglobulins are normal. (See also Overview of Immunodeficiency Disorders .) The immune system produces several classes of immunoglobulins, such as immunoglobulin A (IgA), IgD, IgE, IgG, and IgM. Each class helps protect the body from infection in a different way (see also Antibodies ). Deficiency of one or more types of immunoglobulin increases the risk of serious infection. The level of any immunoglobulin class may be low, but the most commonly affected class is IgA. 