Primary Immune Deficiency Diseases (PIDD)

Understanding PIDD

Primary immune deficiency disease (PIDD) represents a group of chronic disorders which cause the immune system to function improperly. The immune system may not produce enough antibodies or may produce antibodies which do not function as they should. This is different from a secondary immune deficiency where the cause can be identified and, if treated, the immune deficiency may resolve. PIDD is hereditary and may have environmental factors that trigger the condition. There is no cure, although many of these diseases once definitively diagnosed can become quite manageable. There are approximately 400 different forms of PIDD. Some are mild and only affect one component of the immune system. Others can be severe and affect multiple components. PIDD can affect anyone and can be diagnosed in the first year of life or well into adulthood.

Symptoms of PIDD

Symptoms of primary immune deficiency disease (PIDD) are recurrent infections. The major role of the immune system is to protect against foreign invaders: bacteria, fungi and viruses. In PIDD, the deficiency occurs in a part of the immune system, in a type of white blood cells called lymphocyte cells (either T-cell or B-cell origin). Other blood cells that play a key role in the immune system may also be affected. When there is a deficiency, the immune system can no longer provide proper protection, and infections occur. These infections may be frequent and involve unusual bacteria, viruses or fungi. They may be difficult to treat to the point they become severe and require hospitalization. These infections may affect the respiratory system, the skin, the gastrointestinal tract and even the brain.

Diagnosing PIDD

Diagnosing primary immune deficiency disease (PIDD) can be very difficult and may take a long time. Many adults report constant illness for many years before receiving a diagnosis and appropriate treatment. Because PIDD is uncommon, a physician may not readily test the immune function of someone presenting with recurrent infections. Having recurrent infection interferes with a normal lifestyle and may cause people to miss school and work.

Diagnostic workup may include:

• Detailed assessment of the infection history.
• Height and weight, especially in children as they fail to thrive when they have recurrent infections.
• A complete blood count to look at the various white cells, which play a major role in fighting infection.
• An immunoglobulin panel to look at the level of the different antibodies.
• Testing the immune system's ability to mount a response by giving certain vaccines and then drawing blood to check response to the immunization.

Treatment of PIDD

Since there are many types of primary immune deficiency disease (PIDD), treatment options may vary. These include close clinical observation and monitoring, treating suspected infections with antibiotics, and immune globulin replacement therapy. Immune globulin is extracted from a large pool of human plasma and contains all the important antibodies present in the normal population. Immune globulin therapy can be administered into the blood stream intravenously (IVIG) or under the skin subcutaneously (SCIG). In some cases, such as severe combined immunodeficiency, bone marrow transplant is necessary.

Resources:

• The Jeffrey Modell Foundation

Reference:

• Immune Deficiency Foundation