Diagnoses & Conditions

Selective Antibody Deficiency (SAD)

Understanding SAD

Selective Antibody Deficiency (SAD) is characterized by normal or near normal immunoglobulin levels and an impaired antibody response. An inability to produce antibodies may result in the patient being susceptible to certain kinds of infections, but not others.

Symptoms of SAD

Patients with Selective Antibody Deficiency (SAD) may have symptoms which include recurrent ear infections, sinusitis, bronchitis and pneumonia. Infections in SAD patients are not as severe as patients who have combined deficiencies of immunoglobulin types G, A and M (IgG, IgA and IgM) such as agammaglobulinemia or Common Variable Immune Deficiency.

Diagnosing SAD

An evaluation typically includes measurement of total IgG, IgG subclasses and antibody titers to specific bacteria such as tetanus, diphtheria, and/or Streptococcus pneumoniae. When the total IgG or subclasses are low, a more profound immunodeficiency is usually present.

Treating SAD

Patients with Selective Antibody Deficiency (SAD) who frequently suffer recurrent or chronic infections of the ears, sinuses, bronchi and lungs require antibiotics. Immune globulin replacement therapy is needed for patients who fail to make antibodies against proteins or polysaccharide antigens. Immune globulin therapy can be administered into the blood stream intravenously (IVIG) or under the skin subcutaneously (SCIG).


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