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Selective Immunoglobulin Deficiency

By James Fernandez, MD, PhD, RJ Fasenmyer Center for Clinical Immunology

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.

There are 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 Acquired Immunity : Antibodies).

The level of any immunoglobulin class may be low, but the most commonly affected class is IgA.

Selective IgA deficiency

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 IgA deficiency is the most common immunoglobulin abnormality. It may be caused by a mutation in a specific gene or by a drug, such as phenytoin (used to treat seizure disorders) or sulfasalazine (used to treat rheumatoid arthritis). How the gene mutation is inherited is unknown, but having a family member with selective IgA deficiency increases the risk by about 50 times

Symptoms

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 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, antibodies against IgA trigger a severe allergic ( anaphylactic) reaction the next time such people are given a blood transfusion or immune globulin.

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

  • Blood tests to measure immunoglobulin levels

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.

Treatment

  • 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 a medical identification bracelet or tag to alert doctors to take precautions against such reactions.

Selective IgA deficiency that results from taking a drug usually resolves if the drug is stopped.

Drugs Mentioned In This Article

  • Generic Name
    Select Brand Names
  • DILANTIN
  • AZULFIDINE

* This is the Consumer Version. *