Selective IgA deficiency results in a low level of immunoglobulin A (IgA). Levels of IgG and IgM are normal.
Most people with selective IgA deficiency have few or no symptoms, but some have chronic lung infections, sinusitis, and other disorders.
Doctors diagnose the disorder by measuring levels of immunoglobulins in the blood.
Antibiotics are used to treat or sometimes to prevent infections.
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.
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.
Selective IgA deficiency is the most common primary immunodeficiency
Some people with selective IgA deficiency produce antibodies against IgA if they are exposed to IgA in blood transfusions or immune globulin (antibodies obtained from the blood of people with a normal immune system). Rarely, these antibodies against IgA trigger a severe allergic (anaphylactic) reaction the next time such people are given a blood transfusion or immune globulin.
Symptoms of Selective IgA deficiency
Most people with selective IgA deficiency have few or no symptoms. Others develop chronic lung infections, sinusitis, allergies, asthma, nasal polyps, chronic diarrhea, or, rarely, autoimmune disorders, such as systemic lupus erythematosus (lupus) or inflammatory bowel disease (which usually causes gastrointestinal symptoms that often recur or that may be serious). A few people develop common variable immunodeficiency over time.
Some people improve spontaneously. Life span is usually unaffected. If an autoimmune disorder or another immune disorder (such as common variable immunodeficiency) develops, life span may be shortened.
Diagnosis of Selective IgA deficiency
Blood tests to measure immunoglobulin levels before and after vaccinations
Doctors suspect selective IgA deficiency in people if they have
Recurring infections
An anaphylactic reaction to a blood transfusion or to immune globulin
Gastrointestinal symptoms that may result from inflammatory bowel disease
Family members who have selective IgA deficiency, common variable immunodeficiency, or an autoimmune disorder
Blood tests to measure immunoglobulin levels are done to confirm the diagnosis.
Normally, the body’s immune system responds to a vaccine by producing substances (such as antibodies) and mobilizing white blood cells that recognize and/or attack the specific bacteria or virus represented in the vaccine. Then whenever people who have been vaccinated are exposed to the specific bacteria or virus, the immune system automatically produces these antibodies and takes other action to prevent or lessen illness. People with selective IgA deficiency do not produce antibodies in response to certain kinds of vaccines. Doctors measure IgA antibody (immunoglobulin) levels before and after vaccinations. Lack of increase in IgA after vaccination helps to make the diagnosis.
Treatment of Selective IgA deficiency
Antibiotics to treat or sometimes to prevent infections
Use of a medical identification bracelet or tag by people who have had an anaphylactic reaction to a blood transfusion or immune globulin
Usually, no treatment of selective IgA deficiency is needed.
Antibiotics are given to people who have an infection. If the disorder is severe, antibiotics are given in advance to prevent infections from developing.
People who have had an anaphylactic reaction to a blood transfusion or immune globulin should wear medical identification to alert doctors to take precautions against such reactions.
Selective IgA deficiency that results from taking a medication usually resolves if the medication is stopped.
More Information
The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.
Immune Deficiency Foundation: Selective IgA deficiency: Comprehensive information on selective IgA deficiency, including information on diagnosis and treatment and advice for people affected
