Primary immunodeficiency

Introduction

Primary immunodeficiency disorders — also called primary immune disorders — are immune system defects that can permit recurrent infections and other problems. Some of these disorders are passed down from parents to children (inherited). Many people with primary immunodeficiency are born missing some of the body's immune defenses, making them more susceptible to germs that cause infections. Between 25,000 and 50,000 people in the Unites States live with a primary immunodeficiency disorder.

According to the World Health Organization, there are over 100 different types of primary immunodeficiency. What type you have depends on which genetic defect is present. Examples include:

Common variable immune deficiency (hypogammaglobulinemia)
Selective IgA deficiency
X-linked agammaglobulinemia (Bruton's disease)
Severe combined immune deficiency
In some cases, untreated primary immunodeficiency can lead to long-term health problems, including permanent damage to organs such as the ears or lungs, or physical disability.

Signs and symptoms

One of the most common signs of primary immunodeficiency is an increased susceptibility to infection. You may have infections that are more frequent, longer lasting or harder to treat than are the infections of someone with a normal immune system. You may also get infections that a person with a healthy immune system would not get (called opportunistic infections). However, signs and symptoms differ depending on the particular type of disorder you have, and signs and symptoms also vary from person to person.

Signs of primary immunodeficiency can include:

Frequent and recurrent ear infections, pneumonia, meningitis, bronchitis, sinus infections or skin infections
Blood infections
Inflammation and infection of internal organs, such as the liver
Rheumatic disorders (such as lupus or arthritis)
Thyroid disease
Blood disorders, such as low platelet counts or anemia
Digestive problems, such as cramping, loss of appetite, nausea and diarrhea
Delayed growth and development
Causes

Many primary immunodeficiency disorders are inherited — passed down from one or both parents. It is the result of faulty DNA — the genetic code that acts as a blueprint for producing the cells that make up the human body. In primary immunodeficiency, faulty genes mean that the immune system develops lacking one or more of the body's defenses, or with defenses that don't work correctly.

Risk factors

Having a family history of a primary immune deficiency disorder increases your risk of having primary immunodeficiency. Unlike other acquired immune system disorders you can catch — such as HIV/AIDS — a primary immunodeficiency disorder cannot be spread from one person to another.

When to seek medical advice

If you or your child has frequent, recurrent or severe infections, or infections that don't respond to treatment, talk to your doctor. While primary immune deficiencies are rare, early diagnosis and treatment can prevent infections that can cause long-term problems.

The 10 warning signs of primary immunodeficiency
1. Eight or more new ear infections within one year
2. Two or more serious sinus infections within one year
3. Two or more months taking antibiotics with little effect
4. Two or more pneumonias within one year
5. Failure of an infant to gain weight or grow normally
6. Recurrent, deep skin or organ abscesses
7. Persistent thrush in mouth or elsewhere on skin, after age one
8. Need for intravenous antibiotics to clear infections
9. Two or more deep-seated infections
10. A family history of primary immune deficiency
Adapted from Jeffrey Modell Foundation and the American Red Cross

Screening and diagnosis

To help decide whether recurrent infections could be due to primary immunodeficiency, your doctor will begin by asking a number of questions, such as what health problems you have, how long infections last, how severe they are and whether they respond to treatment. Your doctor will also want to know whether any close relatives have an inherited immune system disorder. Your doctor will perform a physical examination to look for clues that may indicate the cause of your illness. Primary immune disorders are rare, so your doctor will want to be sure your signs and symptoms aren't caused by a more common health problem. If your doctor suspects that you may have a primary immune disorder, you may need to see an immunologist, a doctor who specializes in immune system disorders.

There are several tests used to diagnose an immune disorder. They include:

Blood tests. In most cases, blood tests can reveal abnormalities in the immune system that indicate an immune deficiency disorder. Tests can determine if you have normal levels of immunoglobulin (infection fighting proteins) in your blood. Tests can measure the levels of different blood cells and immune system cells. Abnormal numbers of certain cells can indicate an immune system defect. Other blood tests can determine if your immune system is responding properly and producing antibodies — cells that identify and kill foreign invaders such as bacteria or viruses.
Evaluating infections. If you have an infection that's not responding to standard treatment, your doctor may do tests to try to identify exactly what germs are causing it.
Prenatal testing. Parents who've already had a child with a primary immunodeficiency disorder may want to have testing for certain immunodeficiency disorders done during future pregnancies. Samples of the amniotic fluid, blood or cells from the tissue that will become the placenta (chorion) are tested for abnormalities. In some cases, DNA testing is done to test for a genetic defect. Test results make it possible to prepare for a bone marrow transplantation soon after birth, if necessary.
Complications

Complications caused by a primary immunodeficiency disorder vary, depending on what particular disorder you have. They can include:

Recurrent infections
Damage to heart, nervous system or digestive tract
Slowed growth and increased risk of cancer
Treatment

Treatments for primary immunodeficiency involve preventing and treating infections, boosting the immune system and treating the underlying cause of the immune problem. In some cases, primary immune disorders are linked to a serious illness such as an autoimmune disorder or cancer that also needs to be treated.

Managing infections

Antibiotics. Infections are typically treated with antibiotics. In cases where infections don't respond to standard medications, hospitalization and treatment with intravenous (IV) antibiotics may be necessary. Some people need a long-term regimen of antibiotics to prevent infections from occurring and to prevent permanent damage to the lungs and bronchial tubes.
Treating symptoms. You may need medications to relieve symptoms caused by infections, such as ibuprofen for pain and fever, decongestants for sinus congestion, and expectorants to help clear your airways.
Treatment to boost the immune system

Immunoglobulin therapy. Also called gamma globulin therapy, this treatment can be a lifesaver for people who have an antibody deficiency. Immunoglobulin consists of antibody proteins needed for the immune system to fight infections. It's extracted from blood obtained from a large pool of healthy donors and then purified. Originally this medication was given as a shot into the muscle. New, more effective formulations can be either injected into a vein through an IV line, or inserted underneath the skin (subcutaneous infusion). Treatment with intravenous gamma globulin is needed every few weeks to maintain sufficient levels of immunoglobulins. Subcutaneous infusion is needed once or twice a week.
Gamma interferon therapy. Interferons are naturally occurring substances that fight viruses and stimulate immune system cells. Gamma interferon is a man-made (synthetic) substance given as an injection in the thigh or arm three times a week. It's used to treat chronic granulomatous disease, one form of primary immunodeficiency.
Treatment with adenosine deaminase (ADA). A rare primary immune disorder called severe combined immunodeficiency (SCID) causes a deficiency of ADA, an important immune system enzyme. A certain type of ADA made from cows is combined with polyethylene glycol (PEG), which makes the medication more effective. This medication, also called PEG-ADA, will not cure SCID, but regular injections given one to two times a week can improve immune system function.
Treatments to cure primary immunodeficiency

Bone marrow transplantation. Bone marrow transplantation offers a permanent and dramatic cure for several forms of life-threatening immunodeficiency. With this treatment, normal bone tissue is removed from a healthy person and transferred to the person with immunodeficiency. Blood used to replace the defective bone marrow cells can also be obtained from the placenta at birth (cord blood banking). Because all blood cells — including the cells that fight infection — are produced by bone marrow cells, a successful bone marrow transplant essentially replaces the defective immune system with a healthy one. For bone marrow transplantation to work, the donor — usually a parent or other close relative — must have body tissues that are a close biological match to those of the immunodeficient person. Marrow that isn't a good match may be rejected by the immune system. But even with a good match, bone marrow transplants don't always work.
Gene therapy. Researchers hope this treatment will one day be a cure for primary immune disorders and many other conditions. Gene therapy actually replaces defective genes with genes that work correctly. A harmless virus is used to carry the genes into the body's cells. In turn, the newly introduced genes trigger the production of healthy immune system enzymes and proteins. Experts have identified many of the genes that cause primary immune deficiencies — but they still need to work out problems such as how to get the replacement genes into a specific part of a chromosome. Although the technique has shown promise in some initial trials, gene therapy is still experimental.
Prevention

Primary immune disorders are genetic, and there is no way to prevent them. But when you have a weakened immune system, you can take steps to prevent infections:

Use good hygiene. Wash your hands and skin with mild soap, and brush your teeth twice a day.
Eat right. A healthy, balanced diet can help prevent infections.
Avoid exposure. Stay away from people with colds or other infections and avoid crowds of people.
Take preventive medications. You may need to take a regular dose of antibiotics to prevent infection.
Check with your doctor about which vaccinations you should have.

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