The main function of the immune system is to protect against infections. When the immune system is compromised, due to various reasons, immunodeficiency occurs. This results in recurrent, unusual and/or difficult to treat infections. The most severe types of immunodeficiency allow the germs that only produce a mild illness in those with normal immune systems to cause serious, or even deadly, infections. But many forms of primary immunodeficiency respond well to treatment and patients can take part in most normal daily activities.
There are two categories of immunodeficiency disorders, primary and secondary. Primary immunodeficiency disorders (PIDD) occur due to hereditary or genetic causes. Secondary immunodeficiency disorders result from environmental factors such as HIV infection, chemotherapy medications or malnutrition.
For many years, PIDD was believed to be relatively rare because only more extreme versions of the disorder were known. However, now a much wider spectrum of PIDD has been established. The most severe types of primary immunodeficiency are often discovered early in childhood, while milder forms may remain undiagnosed until adolescence or even adulthood. Some variants never result in symptoms and a segment of patients who have them may not ever be aware of it.
Symptoms of Primary Immunodeficiency
Dozens of different PIDDs are known, ranging in severity from mild to severe. The problem may stem from a malfunction in one part of the immune system or in multiple parts. People with PIDD are highly susceptible to developing infections, so they may incur infections more often or for a longer duration than what is experienced by others. The types of infections vary among individuals, but may include blood infections, pneumonia, bronchitis, meningitis, ear infections, sinus infections and skin infections. Often, these infections do not adequately respond to the typical treatment regimens.
PIDDs may also lead to other conditions and health issues that require medical treatment. These can vary greatly, depending on the type of PIDD and which areas of the immune system are weakened, but may include:
- Developmental delays and slow growth in children
- Inflammation and damage to internal organs
- Autoimmune diseases
- Anemia or other problems of the blood
- Digestive difficulties
Causes of Primary Immunodeficiency
PIDDs are typically genetically based. A child often develops a PIDD when he or she inherits certain defective or missing genetic material from the DNA passed down by a parent. Therefore, if there is a family history of PIDD, a child will have a higher risk of being born with some form of this condition.
Diagnosis of Primary Immunodeficiency
An allergist/immunologist is specifically trained in the diagnosis of PIDD based on a careful medical history and immunological testing. In order to make an accurate diagnosis of PIDD, the doctor will need information on the type of symptoms the patient has experienced, their severity and how well they are managed by standard treatments. A complete medical and family history and a physical examination are necessary as well to determine whether the infections a patient has developed are due to a PIDD or another cause.
To confirm a suspected diagnosis of PIDD, the doctor will likely perform a number of tests. Blood tests can provide a lot of information on the level of immune system functioning such as the quantity of red blood cells, white blood cells, platelets and immunoglobulin levels. Tests may also be run on the skin to elicit an immune system reaction. In addition, if there is a known family history of PIDD, prenatal screenings may be recommended to learn whether a baby is going to be born with the disorder and if so, begin a treatment regimen in infancy in certain cases.
Treatment of Primary Immunodeficiency
The most effective form of treatment will vary based on the particular type of PIDD. Depending on the results of diagnostic testing, an allergist/immunologist will be able to develop and coordinate a treatment plan for the specific PIDD. Steps are taken to strengthen the immune system as much as possible as well as to prevent infections from developing and resolve any infections that are already present. This may include the aggressive use of antibiotics, immunoglobulin replacement or bone marrow transplant, among other options.