Primary Immunodeficiency (PI)

Your immune system helps your body fight infections. People with primary immunodeficiency (PI) have an immune system that does not work correctly. This means that people with PI are more likely to get and become very sick from infections.

There are more than 400 types of PI that vary in severity, which affects how early they are detected. In some cases, a person with a mild form may not find out that they have PI until adulthood. In other cases, the disorder causes problems in infancy and is found soon after birth. All states include testing for one type of PI called severe combined immunodeficiency (SCID) as part of newborn screening. Treatments can help the immune system work better. Which treatment works best depends on the type of PI a person has.

Signs and symptoms of PI

People with PI are more likely to have

More frequent or repeated infections, such as
Infections that last longer than in most people
Infections that are hard to treat and do not respond to antibiotics or require IV antibiotics
Infections that are more severe and require hospitalization, such as sepsis or abscesses (pus-filled infections) of internal organs
Infections that most people don’t get (sometimes called opportunistic infections)
Lack of weight gain or growth in an infant (failure to thrive)
Digestive problems, such as chronic diarrhea

People with PI are more likely to have autoimmune disorders and certain blood disorders. Because your immune system protects your body against cancer, people with PI are more likely to have certain cancers. In some cases, PI is due to a genetic disorder that involves other health problems, such as 22q11.2 deletion syndrome (also called DiGeorge syndrome).

Talk to your doctor if you think that you or your child has signs of PI. Your doctor might refer you or your child to a clinical immunologist, a doctor who specializes in the immune system. You can use the American Academy of Allergy, Asthma, and Immunology’s Find an Allergist/Immunologist tool to find a doctor near you.

PI often has an underlying genetic cause and can run in families. Sharing your family history of PI with your doctor can be important for your and your children’s health or if you are pregnant or planning a pregnancy. If you or your child have been diagnosed with PI, be sure to share this information with your family members. Your doctor might refer you for genetic counseling and testing if you have been diagnosed with PI or have a family health history of PI.

Prevention and treatment for people with PI

Early diagnosis can help prevent or delay some of the health problems caused by PI. Left untreated, some types of PI can result in serious health problems, including organ damage, and even death. Even with treatment, most PI do not have a cure.

Taking steps to prevent infection is very important if you have PI. These steps include

Washing your hands the right way
Taking good care of your teeth
Maintaining healthy habits, including being physically active, eating healthy, and getting enough sleep
Avoiding exposure to people who are sick and crowds
Asking your doctor which vaccinations are safe for you. In some cases, people with PI cannot have live vaccines such as rotavirus, chickenpox, oral polio, and measles, mumps, rubella. Newborn screening for SCID can find babies with this PI early, before they receive these vaccines.

Treatments vary, depending on the type of PI, and can include

Antibiotics to prevent certain infections
Treatments that help your immune system work better (including immunoglobulin replacement therapy and interferon-gamma therapy)
Growth factors to help increase the number of white blood cells, which are part of the immune system
Stem cell transplant to provide your body with working immune cells from another person (donor)
Gene therapy to replace the gene that does not work correctly with one that does

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