Author: Brian Wu PhD. MD Candidate, Keck School of Medicine, Los Angeles, USA; Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, September 2015.
IgA is immunoglobulin type A, a protein produced in the bone marrow by plasma cells. IgA is found in mucous membrane secretions, including vaginal secretions, semen, tears, saliva, colostrum and secretions from the respiratory and gastrointestinal tract.
Patients with selective IgA deficiency have normal levels of all immunoglobulins except for IgA. Other component of the immune system such as phagocytes, complement proteins and T cells are normal.
Selective IgA deficiency is one of the most common primary immunodeficiency diseases. It occurs in the Caucasian population in 1 in every 500–700 births. It is much less common in other races.
The exact cause of selective IgA deficiency is unknown. Genetic inheritance is responsible for around a quarter of all cases. Drug-induced IgA deficiency may also occur.
Patients with selective IgA deficiency may be asymptomatic, mildly ill, or seriously ill (25–50%). Their presentations fall into three broad categories:
Diagnosis of selective IgA deficiency is based on:
There is no cure for selective IgA deficiency and it is currently impossible to treat it with immunoglobulin replacement therapy. Treatment is aimed at specific signs and symptoms such as:
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