Selective deficiency of IgA is the most common immune deficiency disorder. Persons with this disorder have low or absent blood levels of a special protein called immune globulin A.

IgA deficiency is inherited, which means it's passed down through families. 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.

Persons with this condition often have chronic diarrhea caused by intestinal infections. There are often frequent ear, sinus, and lung infections.

Other symptoms include mouth infections and unexplained asthma or bronchiectasis.

There may be a family history of IgA deficiency. Tests that may be done include:

• Serum immunoelectrophoresis
• Quantitative immunoglobulins (serum IgA extremely low or absent)

No specific treatment is available. Some people gradually develop normal levels of IgA without treatment. Individual infections should be treated with appropriate antibiotics. In some cases, longer courses of antibiotics may be needed to prevent recurring infection.

Autoimmune disease treatment is based on the specific problem.

NOTE: Persons with a complete absence of IgA should not be given gamma globulin. Such treatment may lead to allergies or life-threatening anaphylactic shock.

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 like rheumatoid arthritis and lupus erythematosus, may develop.

Patients with IgA deficiency may develop antibodies to IgA, and can have severe, even life-threatning reactions to transfusions of blood and blood products. If transfusions are necessary, the blood should ideally come from a donor who is also IgA-deficient.

Consider genetic counseling if there is 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 the provider if gamma globulin is suggested as a treatment for any condition.

Genetic counseling may be of value to prospective parents with a family history of selective IgA deficiency.

Hoffman R, Benz EJ, Shattil SS, et al. Hematology: Basic Principles and Practice. 4th ed. Orlando, Fl: Churchill Livingstone; 2005.

Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 6th ed. London: Churchill Livingstone; 2005.