Primary Immunodeficiency

Diagnosis

To diagnose a primary immunodeficiency disorder, a healthcare professional asks about a history of frequent or severe illnesses and whether any close relatives have an inherited immune system disorder. A physical examination is also performed to look for signs of immune system problems.

Several tests may be used to confirm the diagnosis.

Blood tests
Blood tests can show whether levels of infection-fighting proteins, called immunoglobulins, are within the typical range. These tests also measure different types of blood and immune system cells. Levels that are higher or lower than expected may point to an immune system defect.

Blood testing can also show how well the immune system responds to infection. A healthy immune system makes proteins called antibodies that identify and attack bacteria, viruses and other invaders.

Prenatal testing
Parents who already have a child with a primary immunodeficiency disorder may choose testing during future pregnancies. Samples of amniotic fluid, blood or cells from the tissue that becomes the placenta, called the chorion, can be tested for immune system abnormalities.

In some cases, DNA testing is used to identify a genetic cause. Early diagnosis allows planning for treatment shortly after birth if needed.

Treatment

Treatment for primary immunodeficiency disorders focuses on preventing infections, treating infections quickly, strengthening the immune system and addressing the root cause of the disorder when possible. Some immune deficiencies are associated with serious conditions such as autoimmune diseases or cancer, which also require treatment.

Managing infections
Managing infections is a key part of care and may include:

• Treating infections quickly and aggressively with antibiotics. Treatment may last longer than usual, and infections that do not respond may require hospitalization and intravenous antibiotics.

• Preventing infections through long-term antibiotic therapy for people at high risk of repeated respiratory infections or permanent lung and ear damage.

• Avoiding certain vaccines. Children with primary immunodeficiency often cannot receive vaccines that contain live viruses, such as oral polio or measles-mumps-rubella.

Immunoglobulin therapy
Immunoglobulin therapy supplies the antibodies needed to fight infection. It may be given through a vein every few weeks or under the skin once or twice a week. This treatment helps reduce infections but does not cure the immune disorder.

Treatment to restore the immune system

Stem cell transplantation
Stem cell transplantation can offer a permanent cure for some severe, life-threatening immunodeficiency disorders. Healthy stem cells are transplanted into the affected person, allowing a normally functioning immune system to develop. Stem cells may come from bone marrow or from cord blood collected at birth.

The donor, often a parent or close relative, must closely match the recipient’s tissue type. Even with a good match, stem cell transplantation does not always succeed. Before the transplant, chemotherapy or radiation is often used to destroy existing immune cells, which temporarily increases the risk of infection.

Gene therapy
Gene therapy involves removing stem cells from the person with primary immunodeficiency, correcting the faulty gene in a laboratory, and returning the corrected cells through an intravenous infusion. Because the person’s own cells are used, a donor is not required. This treatment is currently available for only a small number of immunodeficiency disorders, but research and clinical trials are ongoing.

Depending on the specific type of immune disorder, other treatments may be used. These can include enzyme replacement therapy or transplantation of the thymus, the organ behind the breastbone that plays a key role in producing T cells.