Your immune system keeps you healthy by fighting off germs. But people living with primary immune deficiency disease (PI, or PIDD as your doctor may refer to it) have an immune system that is not working correctly.

There are more than 200 types of PI currently recognized by the World Health Organization. It is estimated that approximately 250,000 individuals (or 1 in 1,200) in the United States are diagnosed with PIDD. Although rare, PI is not as uncommon as once believed.1,4

  • According to the National Institutes of Health, about 500,000 people may have PI and not know it2
  • About 80% of people with PI are diagnosed before the age of 20, but PI may not be recognized until adulthood3
  • Some examples of PI are common variable immunodeficiency (CVID), selective immunoglobulin A (IgA) deficiency and X-linked agammaglobulinemia (XLA)
  • See the FAQ about PI below for more information

For people living with PI, infections may not go away or can come back often, even with the use of antibiotics. Infections may be common, severe, long-lasting, or hard to cure. Appropriate therapy can help prevent complications associated with PI.

For more information about PI and treatment options, click here.

Websites of related resources

Frequently Asked Questions

What is PI?

PI, sometimes referred to as PIDD, is short for primary immune deficiency disease. Your immune system keeps you healthy by fighting off germs with antibodies. People living with PI have an immune system that is not working properly. The World Health Organization recognizes more than 200 types of PI.4

For people living with PI, infections may not go away or can come back often, even with the use of antibiotics. Infections may be common, severe, long-lasting, or hard to cure. Some patients with PI require Ig replacement; others will need other types of therapy.

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Is PI contagious?

PI is a genetic condition that people are born with. It is not contagious, nor can it be spread to other people. Some people associate the words “immune deficiency” with the AIDS virus. However, AIDS is a secondary immune deficiency, not a primary immune deficiency (PI). A person with PI poses no risk to other people.1

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What are the symptoms of PI?

PI has no unique or specific symptoms. It shares similar symptoms with many other conditions–symptoms that can range from mild to severe and can be mistaken as ordinary infections, such as infections of the ears, gastrointestinal tract, sinuses, and/or lungs. Some patients develop polyarthritis and chronic pulmonary complications, as well as inflammation in joints.2

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If there are no unique or specific symptoms of PI, are there warning signs?

In 2012, the Jeffrey Modell Foundation created the 10 Warning Signs of PIDD to help raise awareness of these disorders. The following lists are the Modell Warning Signs for Children and Adults:

Modell Warning Signs for Children:

  1. Four or more new ear infections within one year
  2. Two or more serious sinus infections within one year
  3. Two or more months on antibiotics with little effect
  4. Two or more pneumonias within one year
  5. Failure of an infant to gain weight or grow normally
  6. Recurrent, deep skin or organ abscesses
  7. Persistent thrush in mouth or fungal infection on skin
  8. Need for intravenous antibiotics to clear infections
  9. Two or more deep-seated infections including septicemia
  10. A family history of PI

Modell Warning Signs for Adults:

  1. Two or more new ear infections within one year
  2. Two or more new sinus infections within one year, in the absence of allergy
  3. One pneumonia per year for more than one year
  4. Chronic diarrhea with weight loss
  5. Recurrent viral infections (colds, herpes, warts, condyloma)
  6. Recurrent need for intravenous antibiotics to clear infections
  7. Recurrent, deep abscesses of the skin or internal organs
  8. Persistent thrush or fungal infection on skin or elsewhere
  9. Infection with normally harmless tuberculosis-like bacteria
  10. A family history of PI

This information is available on the Jeffrey Modell Foundation website www.info4pi.org.

If you or someone you know is affected by 2 or more of the warning signs above, speak to a physician about the possible presence of an underlying primary immunodeficiency. Your physician will likely refer you to an immune system specialist, or immunologist.

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How is PI diagnosed?

An immunologist can help your physician diagnose and evaluate your immune system. This evaluation might include a detailed medical history, a physical exam, blood tests, and vaccines to test how well your immune system responds.

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How many people have PI?

It is estimated that approximately 250,000 individuals (or 1 in 1,200) in the United States are diagnosed with PIDD.1 Although rare, PI is not as uncommon as once believed. According to the National Institutes of Health, about 500,000 people may have PI and not know it.2 More than 200 types of PI are currently recognized by the World Health Organization.4

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How is PI treated?

One treatment option for certain patients with PI is immunoglobulin therapy, or Ig therapy. This therapy replaces or supplements the antibodies in the immune systems of people living with PI. The immunoglobulin used in Ig therapy is made from the blood plasma of carefully screened donors. It is manufactured and purified under strict conditions for safety. The risk of transmission of infectious agents cannot be completely eliminated.

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References
1. Boyle JM, Buckley RH. Population prevalence of diagnosed primary immunodeficiency diseases in the United States. J Clin Immunol. 2007;27:497-502.
2. Modell V. The impact of physician education and public awareness on early diagnosis of primary immunodeficiencies. Robert A. Good Immunology Symposium. Immunol Res. 2007;38:43-47.
3. Kumar A, Teuber SS, Gershwin ME. Current perspectives on primary immunodeficiency diseases. Clin Dev Immunol. 2006;13(2-4):223-259.
4. Immune Deficiency Foundation. Specific Disease Types. http://primaryimmune.org/about-primary-immunodeficiencies/specific-disease-types/
Accessed January 13, 2015.

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