Overview
Selective IgA deficiency is the lack of a disease-fighting antibody in the immune system called immunoglobulin A (IgA). People with this condition usually have typical levels of other immunoglobulins (im-u-no-GLOB-u-lins).
An immunoglobulin is an antibody produced by immune system cells to fight bacteria, parasites and other agents that cause illness. IgA antibodies circulate in the blood and are found in tears, saliva, breast milk, and fluids released from the lining of the airways, lungs and digestive system.
Most people with selective IgA deficiency have no symptoms. But some people who have selective IgA deficiency have frequent illness of the airways, lungs and digestive system.
Selective IgA deficiency may increase the risk of other conditions related to the immune system, such as allergies, asthma, rheumatoid arthritis, inflammatory bowel diseases and others.
There is no treatment specifically for selective IgA deficiency. Treatments focus on addressing the frequent, repeat or long-lasting conditions that develop with this immune system disorder.
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Symptoms
Most people with selective IgA deficiency have no symptoms. Some people have illnesses more often than is typical. They also may have a particular illness that returns often. Having frequent illnesses doesn't necessarily mean a person has selective IgA deficiency.
People with selective IgA deficiency may have frequent or repeat episodes of the following:
- Ear infections, particularly in young children.
- Colds.
- Sinus infections.
- Lung illnesses, such as bronchitis or pneumonia.
- Giardiasis, a parasitic illness of the digestive system that causes diarrhea.
Children with frequent illnesses may not eat well or may not gain weight typical for their age.
Causes
Selective IgA deficiency happens when immune system cells don't produce any or produce very few IgA antibodies. The exact reason cells don't produce these antibodies isn't known.
Certain medicines used to treat seizures, epilepsy or rheumatoid arthritis may cause selective IgA deficiency in some people. The deficiency may continue after the medicine is no longer taken.
Risk factors
A family history of selective IgA deficiency increases the risk of the condition. Certain variations of genes appear to be linked to selective IgA deficiency, but no gene is known to directly cause the condition.
Complications
People with selective IgA deficiency are at increased risk of other long-term conditions. These include:
- Allergies and asthma.
- Rheumatoid arthritis.
- Celiac disease.
- Inflammatory bowel disease.
- Common variable immunodeficiency, which is a lack of two or more types of immunoglobulins.
Risk of reaction to blood products
People with selective IgA deficiency are at risk of reactions to blood transfusions or blood products. Because a person's body doesn't make IgA, the immune system may see it as a foreign substance in a blood transfusion or other treatment with blood products.
A reaction may cause high fever, chills, sweating and other symptoms. Rarely, people with selective IgA deficiency have a life-threatening allergic reaction, called anaphylaxis (an-uh-fuh-LAK-sis).
Healthcare professionals recommend wearing a medical bracelet. A bracelet can show that you have selective IgA deficiency and should receive modified blood or blood products.