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 150 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
- 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 or 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 150 types of PI.1
Some, but not all, patients with PI require Ig replacement. Some may need other types of therapy. 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.
Is PI contagious?
PI is a genetic condition that people are born with, and it is not contagious nor can it be spread to other people. Some people hear the words “immune deficiency” and think of the AIDS virus, which is a secondary immune deficiency. A person with PI poses no risk to other people.
What are the symptoms of PI?
PI has no unique or specific symptoms. It shares symptoms with many other conditions–symptoms that can range from mild to severe. Thus, it is often mistaken for ordinary infections, such as infections of the ears, gastrointestinal tract, sinuses, and/or lungs.
If there are no unique or specific symptoms of PI, are there warning signs?
The Jeffrey Modell Foundation (2012) created the 10 Warning Signs of PIDD to help raise awareness of these disorders. The list for children is as follows (variations for adults are noted):
- Four or more new ear infections within one year (two or more for adults)
- Two or more serious sinus infections within one year (in absence of allergy for adults)
- Two or more months on antibiotic with little effect
- Two or more pneumonias within one year (one or more for adults)
- Failure of an infant to gain weight or grow normally
- Recurrent deep abscesses of the skin or internal organs
- Recurrent need for intravenous antibiotics to clear infections
- Persistent thrush or fungal infections
- Two or more deep-seated infections including septicemia (not noted in adult criteria)
- A family history of PIDD
This information is available on the Jeffrey Modell Foundation web site 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 immune deficiency. Your physician will likely refer you to an immune system specialist, or immunologist.
How is PI diagnosed?
An immunologist can help with diagnosis and treatment. When an immunologist evaluates your immune system, the evaluation might include a detailed medical history, a physical exam, blood tests, and vaccines to test how well your immune system responds.
How many people have PI?
There are more than 150 types of PI currently recognized by the World Health Organization.1 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. According to the National Institutes of Health, about 500,000 people may have PI and not know it.2
How is PI treated?
One treatment option for patients with PI is immunoglobulin therapy, or Ig therapy. This therapy replaces either the missing or the low number of antibodies in 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.
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.