Selective deficiency of IgA is the most common immune deficiency disorder. Persons with this disorder have low or absent levels of a blood protein called immunoglobulin A.
Causes, incidence, and risk factors
IgA deficiency is usually inherited, which means it is passed down through families. However, cases of drug-induced IgA deficiency have been reported.
It may be inherited as an autosomal dominant or autosomal recessive trait. It is found in approximately 1 in 700 individuals of European origin. It is less common in people of other ethnicities.
See also: Celiac disease - sprue
Many people with selective IgA deficiency have no symptoms.
Symptoms include frequent episodes of:
- Chronic diarrhea
Conjunctivitis (eye infection)
- Gastrointestinal inflammation including ulcerative colitis, Crohn's disease, and a sprue-like illness
- Mouth infection
Otitis media (middle ear infection)
- Skin infections
- Upper respiratory tract infections
Other symptoms include:
Bronchiectasis (a disease in which the small air sacs in the lungs become damaged and enlarge)
- Unexplained asthma
Signs and tests
There may be a family history of IgA deficiency. Tests that may be done include:
No specific treatment is available. Some people gradually develop normal levels of IgA without treatment.
Infections should be treated with antibiotics. In some cases, longer courses of antibiotics may be needed to prevent infections from coming back.
Those with selective IgA deficiency who also have IgG subclass deficiencies can benefit from immunoglobulin (IVIG) treatments given through a vein.
Autoimmune disease treatment is based on the specific problem.
Note: People with complete IgA deficiency may develop anti-IgA antibodies if given blood products and IVIG. This may lead to allergies or life-threatening anaphylactic shock. These individuals can safely be given IgA-depleted IVIG.
Selective IgA deficiency is less harmful than many other immunodeficiency diseases.
Some people with IgA deficiency will recover on their own and begin to produce IgA in larger quantities over a period of years.
An autoimmune disorder such as rheumatoid arthritis and systemic lupus erythematosus,or celiac sprue may develop.
Patients with IgA deficiency may develop antibodies to IgA, and can have severe, even life-threatening reactions to transfusions of blood and blood products. If transfusions are necessary, washed cells may be cautiously given.
Calling your health care provider
Consider genetic counseling if you have a family history of selective IgA deficiency and you plan to have children.
If you have an IgA deficiency, be sure to mention it to your health care provider if IVIG or other blood-component transfusions are suggested as a treatment for any condition.
Genetic counseling may be of value to prospective parents with a family history of selective IgA deficiency.
Ballow M. Primary immunodeficiency diseases. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 258.
Morimoto Y. Immunodeficiency overview. Prim Care. 2008;35(1):159-157.
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