What is IgA Deficiency?
Selective immunoglobulin A (IgA) deficiency is a genetic immunodeficiency condition in which individuals do not make or have very low blood levels of IgA antibodies. IgA antibodies are responsible for fighting infections in mucus membranes throughout the body. These antibodies are important as they play a major role in mucosal surface health. Some with IgA deficiency find themselves with recurrent infections in places such as the ears, sinuses or urinary and intestinal tracts. Additionally, some with selective IgA deficiency may not only suffer from recurrent infections but may take longer to heal from them or need additional rounds of antibiotics to fend off an infection.
It is estimated that 1 in 500 people have selective IgA deficiency. Diagnosis can be established through a blood test measuring immunoglobulin levels in blood serum. For some with IgA deficiency, the condition is ‘silent,’ meaning they no symptoms, however for others it is associated with a heightened risk of infections, allergies, asthma and autoimmune diseases. Some affected by IgA deficiency face serious health issues such as chronic infections or diarrhea. Common autoimmune conditions found with IgA deficiency include rheumatoid arthritis, lupus and celiac disease.
It is currently not possible to replace IgA in a person with an IgA deficiency, so treatment focuses on alleviating specific symptoms (such as using antibiotics for infections) and not treating the underlying issue itself.
What is the Connection between Celiac Disease and IgA Deficiency?
An estimated 2% of people with celiac disease also have selective immunoglobulin A (IgA) deficiency. If someone has IgA deficiency and celiac disease, the IgA deficiency can cause a false negative on a celiac disease antibody test. Therefore when it comes to testing for celiac disease when one is IgA deficient, the following information is important:
People with IgA deficiency should be tested for celiac disease because they are 10 to 20 times likely to develop an autoimmune response to gluten than the general population;
Those with IgA deficiency should be tested for IgG-tTG antibodies instead of IgA-tTG. This is because the IgA-tTG test will not be accurate in those with IgA deficiency.
Where Can I Learn More?
Because IgA deficiency and celiac disease are separate conditions, there is a lot of information available online about each. However, because there is some overlap between the conditions, if you have IgA deficiency, or if you received negative results on your antibody test but still suspect celiac disease, we recommend viewing the specific additional information below related to IgA deficiency and celiac disease to help inform yourself.