Primary Immunodeficiency Symptoms & Causes


We understand that you may want to learn more about your child’s PIDD in order to find the most appropriate treatment. We’ve provided some answers to commonly asked questions in the following pages, and our experts can explain your child’s condition fully.

What is the immune system?

The immune system finds and attacks infectious organisms, including bacteria, viruses and fungi. The immune system is made up of several different types of white blood cells. Each white blood cell type has specialized functions. For instance, neutrophils are important to fight bacteria and fungi, while lymphocytes generally fight viruses. Some T lymphocytes can kill other cells that are infected with a virus, and B lymphocytes make antibodies, which are proteins that fight infection. Usually, many different types of white blood cells work together to fight all kinds of infections. Thus, the immune system is truly a system, and a problem in any part of the system can cause minor infections to become serious ones.

What is primary immunodeficiency?

Primary immunodeficiency disorders (PIDDs) are a group of inherited conditions affecting the immune system. From the time of birth, the immune system of a child with a PIDD does not function properly and cannot fight off infections, due to a problem in white blood cells, such as T lymphocytes or B lymphocytes. A defective immune system can cause children to get sick faster and for longer periods of time from usual childhood infections. These children are also susceptible to infection from ordinarily harmless organisms. Most PIDDs are not deadly, but it is still important for it to be diagnosed and treated early so it does not become life threatening.

There are more than 180 known kinds of PIDDs. Some children with PIDD are born missing certain white blood cell types. For instance, children with severe combined immunodeficiency have an absence of T lymphocytes; those with Kostmann’s syndrome have no neutrophils. Children with other disorders, such as Wiskott-Aldrich syndrome, have normal numbers of lymphocytes, but their lymphocytes have only partial function.

There are six main types of PIDDs based on the part of the immune system that is affected

  • B lymphocytes (antibody) deficiencies
  • T lymphocyte deficiencies
  • combined B and T cell deficiencies
  • phagocyte defects
  • complement deficiencies
  • other forms and unknown causes

B cell deficiencies are the most common type of PIDD

What causes primary immunodeficiency disorders?

Acquired immune deficiencies occur after infections or environmental exposures in people who were previously completely healthy. PIDDs are present at birth, although the symptoms may not begin until later in life, sometimes even in teenage years or adulthood. Thus, PIDDs are not caused by environmental exposures, medications, trauma, diet or events occurring during pregnancy.

PIDDs are genetic disorders, meaning that every cell in the child's body usually carries a defective or mutated gene that causes the disease. Some children with PIDD have relatives with the same disorder. Sometimes the child's parents carry the gene, which puts future children at risk of being born with the same problem. Other times the child developed the defective gene spontaneously, in which case the child's future siblings would not be at risk.

Signs and Symptoms

Although the genetic defect causing the PIDD is present at birth, children with PIDD may not develop symptoms until they are several months old. In some cases, they are not diagnosed until later in childhood or even adulthood. Because PIDDs affect the immune system, children with these disorders develop frequent, severe or unusual infections. Often a simple cold will lead to severe bacterial infections, most commonly pneumonia, bronchitis, sinusitis and ear infections (otitis).

Warning signs that your child may have a PID:

  • infections
    • 4 or more new infection in a year, including infections of the skin and mucous membranes in the eyes, mouth, and genital area
    • infections require intravenous antibiotics
    • 2 or more deep-seated infections such as septicemia
    • persistent thrush (a fungal infection of the mouth)
    • 2 or more serious sinus infections in a year
    • antibiotics have little or no effect over 2 or more months
    • 2 or more pneumonias within a year
  • visible signs
    • severe eczema
    • serious skin infections
    • failure to grow and gain weight in infancy
    • enlarged lymph nodes
    • severe chronic digestive problems such as cramping, and diarrhea
  • internal signs
    • autoimmune disorders such as lupus, rheumatoid arthritis, or type 1 diabetes
    • inflammation and infection of internal organs such as the liver
    • enlarged spleen
  • PIDD in the family

A child that has only one of these symptoms or signs is unlikely to have PIDD. But if a child has several of these symptoms, or has repeated infections in a short period of time, the child could have PIDD.


Q: Will my child be OK?

A: The majority of children with a PIDD live active lives. Sometimes so much so, their condition is not suspected. Early detection, diagnosis and treatment are critical in reducing the risk for chronic illness, permanent organ damage or even death.

Q: Could I have prevented my child from getting PIDD?

A: No. So far, research only shows genetics as the cause for PID. That being said, you can use proper hygiene, provide a healthy diet, avoid exposure to infections and take prescribed medicines to prevent infections from attacking your child’s compromised immune system.

Q: Can PIDD surface later in life, even though it is inherited?

A: Yes. There is a form of PIDD called common variable immunodeficiency that can have the onset of symptoms at any time in life, even though, for most people who are affected it is determined genetically.

Q: Can my child spread their PIDD or contract a PIDD?

A: No. A PIDD is inherited and genetic. So your child cannot give or get a PIDD from being in contact with another person or their germs. However, if your child does have a PIDD, they may be more vulnerable to infections.

Q: Is there a cure?

A: Yes. Stem cell transplantation uses stem cells from a donor, usually a parent or relative, to build a normally functioning immune system. The donor is usually a parent or a relative so the antigens are similar and the patient’s body accepts the donor’s stem cells. However, only the most serious PIDDs are treated this way. Most children with PIDD do not require stem cell transplantation.

Q: Are there other treatments for PIDD?

A: Yes. Many people with PIDD who don’t need a stem cell transplant will be treated with IgG replacement therapy. This provides them with antibodies they cannot make themselves. Many patients will also take various kinds of antibiotics and other medications to prevent certain types of infections.

Questions to ask your child’s doctor

After your child is diagnosed with a PIDD, you may feel overwhelmed with information. It can be easy to lose track of the questions that occur to you.

Lots of parents find it helpful to jot down questions as they arise- that way, when you talk to your child’s doctors you can be sure that all of your questions are answered. If your child is old enough, you may want to suggest that he or she writes down what they want to their health care provider too.

Here are some questions to get you started:

  • How will PIDD medications or treatment impact my child’s academic performance?
  • How may PIDD medications or treatment interact with my child’s other current medication regimens?
  • Will my child’s diet need to change while receiving PIDD medications or treatment?
  • What are some things I can do to minimize my child from being exposed to infections?
  • How can I provide my child with the tools to help themselves if I’m not there?
  • How will their PIDD impact their adult life?
  • What support services are available to help educate my child about their PIDD?
  • What are some steps I should take if my child suffers from a severe infection?
  • What are some other conditions these symptoms could be a sign for?
  • How can I tell if the symptom is for PIDD, another condition or maybe even a PID in combination with another condition?
  • How can I prepare my child for any testing?

In addition to being prepared to ask questions, you may want to be prepared and have the information to be able to answer the following questions from your doctor:

  • When did you first observe these symptoms in your child?
  • What is the frequency of these symptoms?
  • What is the usual duration of these symptoms?
  • What is the frequency of infections?
  • What is the usual duration of the infections?
  • How does your child react to antibiotics for their infections?
  • What was your previous antibiotic regimen for your child?
  • Any family history of PIDD?
    Interactive learning
    Stem cells are a key part ofhematopoietic stem cell transplantation, which is currently the only known cure for PID. Learn from this interactive demonstration on stem cell research.