What is this Condition?

Selective deficiency of immunoglobulin A is the most common immunoglobulin deficiency, appearing in as many as 1 in 800 persons. Immunoglobulin A, the major immunoglobulin in human saliva, nasal and bronchial fluids, and intestinal secretions, guards against bacterial and viral reinfections. Consequently, immunoglobulin A deficiency leads to chronic sinus and respiratory infections, gastrointestinal diseases, and other disorders. The prognosis is good for people who receive correct treatment, especially if they are free of associated disorders. Such people have been known to survive to age 70.

What Causes it?

Immunoglobulin A deficiency is an inherited disorder. It also seems related to autoimmune disorders, because many people with rheumatoid arthritis or lupus are also immunoglobulin A deficient. Some drugs, such as anticonvulsants, may cause temporary immunoglobulin A deficiency.

What are its Symptoms?

Some people with immunoglobulin A deficiency have no symptoms, possibly because their bodies compensate for the deficiency. Among people who do develop symptoms, chronic sinus and respiratory infection is most common. Other effects are respiratory allergy, often triggered by infection; gastrointestinal diseases, such as celiac disease, ulcerative colitis, and regional enteritis; autoimmune diseases, such as rheumatoid arthritis, lupus, hemolytic anemia, and chronic hepatitis; and malignant rumors, such as squamous cell cancer of the lungs, reticulum cell sarcoma, and thymoma.

Age of onset varies. Some children with immunoglobulin A deficiency who have recurrent respiratory disease and middle-ear inflammation may begin to synthesize immunoglobulin A spontaneously as recurrent infections subside and their condition improves.

How is it Diagnosed?

Blood tests confirm diagnosis. Immunologic analyses show serum immunoglobulin A levels below 5 milligrams per deciliter.

Tests may also indicate autoantibodies and antibodies against immunoglobulin G (rheumatoid factor), immunoglobulin M, and cow’s milk.

How is it Treated?

Selective immunoglobulin A deficiency has no known cure. Treatment aims to control symptoms of associated diseases, such as respiratory and gastrointestinal infections, and is generally the same as for a person with normal immunoglobulin A, with one exception: A person with immunoglobulin A deficiency must not receive immune globulin because sensitization may lead to anaphylaxis during future administration of blood products.

If transfusion with blood products is necessary, the risk of side effects can be reduced by using washed red blood cells; it can be avoided completely by crossmatching the person’s blood with that of a donor who’s deficient in immunoglobulin A.