Primary immunodeficiency diseases (PIDD)

What are primary immunodeficiency diseases (PIDD)?

Primary immunodeficiency disease (PIDD) is a group of more than 150 rare hereditary disorders in which the common feature is a defect in a patient's immune system. Children with a PIDD are more prone to infections than are other kids and are at increased risk for certain autoimmune disorders. PIDDs are present at birth.

What are the signs and symptoms of primary immunodeficiency diseases (PIDD)?

Children with PIDDs are usually more susceptible to infections, have infections that won't go away or have recurrent severe infections. Over time, a child with a PIDD may develop more harmful diseases or disorders.

Signs of PIDD in children may include:

• An autoimmune disease such as type 1 diabetes, rheumatoid arthritis or lupus

• Recurrent ear infections, sinusitis, bronchitis, meningitis, skin infections or pneumonia

• Frequent, unusually hard to treat infections

• Blood infections

• Blood disorders, including anemia

• Weight loss or failure to thrive

• Deep abscesses in the skin or internal organs

• Swollen lymph glands

• Infections of internal organs such as the spleen

If your child has recurrent, severe infections or doesn't respond to treatment, see a doctor.

How is primary immunodeficiency diseases (PIDD) diagnosed?

Primary immunodeficiency diseases (PIDDs) are a group of inherited disorders that impair a child's immune system. Unlike secondary, or acquired, immune deficiencies that result from a virus or medications, PIDDs are present at birth. Symptoms usually show up in infancy and can range from mild to severe.

Can I tell if my child has primary immunodeficiency diseases (PIDD)?

Children with a PIDD often have severe, recurrent infections, sometimes requiring hospitalization. Infections may include sinusitis or bronchitis, ear infections or pneumonia. Some children with PIDD have an autoimmune disorder such as type 1 diabetes or lupus. If your child has unusually severe infections, or if you have a family history of PIDD, see a doctor.

Tests and diagnoses

Your child's doctor will begin a diagnosis of primary immunodeficiency diseases (PIDD) by asking you a series of questions such as:

• What are your child's health problems?

• Do the infections respond to treatment?

• How severe are your child's infections and how long do they last?

• Do any close relatives have an inherited immunodeficiency disorder?

The doctor will give your child a physical exam and may perform some tests.

Tests for PIDD include:

• Blood tests - These can reveal whether your child has normal levels of immunoglobulin in the blood. Immunoglobulin is a protein that fights infection. Blood tests can measure levels of other immune system cells as well.

• Prenatal testing - If you're pregnant and you already have a child with a PIDD, your doctor may want to test for it before the baby is born. Amniotic fluid, blood and tissue samples can reveal abnormalities so a PIDD can be treated as soon as your child is born.

What are the causes of primary immunodeficiency diseases (PIDD)?

The human immune system consists of white blood cells that travel through the bloodstream and lymph nodes to stop invading germs and prevent diseases. In many PIDDs, certain types of white blood cells are missing, leaving the body vulnerable to frequent infections.

There are six categories of PIDDs, depending on the part of the immune system affected:

1. Flaws with antibodies (B cells)

2. T-cell deficiencies

3. A combination of both B and T cell problems

4. Abnormal phagocytes

5. Complement deficiencies

6. Idiopathic (unknown) deficiencies

Infections can strike many parts of the body including the respiratory system, brain and spinal cord. Some PIDDs attack certain organs and tissues, while others may curb a child's growth. PIDDs often run in families.

How are primary immunodeficiency diseases (PIDD) treated?

Most primary immunodeficiency diseases (PIDDs) are diagnosed in infancy or early childhood. Most of the 150 or so different types of PIDDs are rare, affecting around 200,000 people in the United States. Although the risk of serious infections is high in children with a PIDD, most can go to school and lead relatively normal lives.

Treatments include preventing and managing infections, boosting the immune system and addressing the underlying deficiency.

Preventing infections

Keeping a child with PIDD healthy may involve avoiding contact with sick people, frequent hand washing and feeding your child a healthy diet. Vaccinations can help prevent certain kinds of illnesses as well. It is also important not to compromise your child's immune system with pollutants such as cigarette smoke.

Managing infections

Antibiotics are usually used to treat infections caused by bacteria. If the infection doesn't respond to typical medications, your child may need intravenous antibiotics in a hospital. Other medications, such as pain relievers, decongestants or expectorants, can help with various symptoms as well.

Stem cell transplants

Curing a PIDD can offer children a permanent solution for a PIDD. Stem cell transplantation involves replacing your child's defective immune system cells with normal stem cells from a donor.

The donor must be a close biological match to your child for the treatment to succeed—usually a parent or sibling. Please note that stem cell transplants don't always work and your child's immune system may be further compromised during the procedure.

Boosting the immune system

• Immunoglobulin (or gamma globulin) therapy is often used to treat PIDDs. Injections of immunoglobulin replace the body's deficiency and help fight off harmful viruses or bacteria.

• Gamma interferon is a synthetic material that helps stimulate immune system cells. It is used to treat a form of PIDD called chronic granulomatous disease. Gamma interferon therapy requires injections three times a week.

• Growth factor therapies can help treat certain types of PIDDs by boosting levels of white blood cells.