What Is IgA Deficiency?
IgA deficiency is a defect in the immune system characterized by an inadequate amount of the antibody class known as immunoglobulin A (IgA). Antibodies are large proteins produced by the body to fight infections caused by invaders, such as bacteria, viruses, fungi, parasites, and other foreign agents. The immune system responds to the protein component (antigens) of these invaders by producing large quantities of specific antibodies, including IgA. These antibodies bind to the antigens on the surface of an invader (bacteria, for example) and prevent them from multiplying, thus halting the spread of disease in the body.
IgA deficiency is the most common immunodeficiency disorder among whites, affecting roughly one in every 600 individuals of Caucasian descent. IgA is found in the saliva, mucous membranes, and intestinal secretions, where it may serve as the first line of defense against various sinus, respiratory, and gastrointestinal infections. Consequently, a deficiency of IgA heightens one’s vulnerability to such infections.
People with IgA deficiency are also more susceptible to certain other disorders, including autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and chronic hepatitis; respiratory allergies and asthma; chronic diarrheal diseases; and some types of cancer, such as squamous cell carcinoma of the lungs and thymoma (cancer of the thymus gland). However, many people with IgA deficiency are relatively healthy and do not suffer from these infections and disorders.
It is important to note that 40 to 50 percent of people with IgA deficiency develop antibodies to IgA itself. This can lead to serious reactions to blood transfusions or other blood products that contain small amounts of IgA. There is currently no cure for IgA deficiency, so treatment is aimed at easing symptoms and controlling associated diseases.
What Causes IgA Deficiency?
- IgA deficiency is most often a hereditary disorder.
Symptoms of IgA Deficiency
- Frequent or chronic infections of the sinuses, lungs, ears, upper respiratory tract, throat, eyes, or gastrointestinal tract
- Mild to severe allergies (e.g., asthma and food allergies)
- Diarrhea or abdominal cramps
IgA Deficiency Prevention
- There is no known way to prevent IgA deficiency.
IgA Deficiency Diagnosis
- The diagnosis is made by detecting low levels of IgA in the blood and the saliva.
- Radioimmunoassay, ELISA, or automated laser nephelometry are performed to measure serum immunoglobulin concentrations.
How to Treat IgA Deficiency
- Antibiotics are prescribed to treat associated bacterial infections. These should be taken for the full term prescribed.
- Nonprescription pain relievers may be taken to treat minor pain and fever. Acetaminophen (not aspirin) should be given to children.
- Patients with IgA deficiency should receive vaccines to protect them against flu viruses and pneumococcal pneumonia.
- Measures must be taken to control underlying disorders that may be associated with IgA deficiency. These include malignant tumors, asthma, and autoimmune disorders (such as rheumatoid arthritis and systemic lupus erythematosus).
When to Call a Doctor
- Make an appointment with a doctor if you or your child develop frequent or persistent infections.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media