Primary immunodeficiencies are inherited, meaning they are passed down from parents to children. 

These immunodeficiencies range from very serious to very mild.  The serious forms are often noticeable at birth or shortly thereafter.  However, very mild forms may not be diagnosed until later in life, during adolescence or young adulthood. 

The World Health Organization has identified more than 80 kinds of primary immunodeficiency diseases.  But, the general category includes more than 100 diseases caused by an immune system that doesn’t function properly. 

• Having infections more often and getting infections that are more severe, longer lasting, and harder to cure than for people with normal immune systems.
• Getting infected with germs that a healthy immune system would be able to get rid of, known as opportunistic infections.
• Having autoimmune problems, meaning that instead of the immune system attacking germs and disease-causing materials, it attacks the body’s own organs and tissues by mistake.

For more information on the symptoms of primary immunodeficiency, check out the 10 Warning Signs of Primary Immunodeficiency. The NICHD is one of the many partners of the Jeffery Modell Foundation, a primary resource for information about primary immunodeficiency, in getting the word out about primary immunodeficiency and its warning signs.

Even though no one treatment works in all cases of primary immunodeficiency, there are many treatment options that can even be combined to make it more likely that primary immunodeficiency can be treated. 

For more information about treatments, see Treatments for Primary Immunodeficiency section of the NICHD booklet Primary Immunodeficiency: When the Body’s Defenses Are Missing.

• Primary Immunodeficiency: When the Body’s Defenses are Missing