The immune system in action

Primary vs. Secondary Immunodeficiency

Immunodeficiency disorders interfere with your immune system’s ability to defend your body against foreign or abnormal cells (such as viruses, bacteria, fungi, and cancer cells) that try to invade or attack your body. These types of disorders occur as a result of a malfunction of the immune system, which leads to infections that develop and recur more frequently, are more severe, and last longer than usual. Immunodeficiency disorders can be caused by a long-lasting serious disorders such as cancer, certain medications, or they can be inherited. There are two different types of immunodeficiency disorders: primary and secondary.

Primary Immunodeficiency

There are over 100 different types of primary immunodeficiency disorders, and all are very rare. This type of immunodeficiency is present from birth and is usually inherited. Primary immunodeficiency disorders are normally diagnosed in infancy or early childhood.

The cause of primary immunodeficiency disorders is a genetic mutation in a part of the immune system. The different forms of primary immunodeficiencies are classified by which part of the immune system is affected by the genetic mutation. Some of the most common affected areas include:

  • Humoral immunity: This involves the B cells, or lymphocytes, which are a type of white blood that help to produce antibodies.

  • Cellular immunity: This involves T cells, which are also lymphocytes and white blood cells, that help to identify and destroy foreign or abnormal cells that attempt to invade your body. Sometimes the genetic mutation affects both B cells and T cells, resulting in humoral and cellular immunity.

  • Phagocytes: This is a type of cell in your immune system that works to ingest and kill microorganisms.

  • Complement proteins: This is a type of protein in your immune system that works to kill bacteria and other foreign cells, as well as make it easier for foreign cells to be identified and ingested.

Secondary Immunodeficiency

Secondary immunodeficiencies are much more common than primary immunodeficiency disorders. A secondary immunodeficiency disorder generally develops later in life as a result of taking certain medications, or from another long-term disorder such as HIV (human immunodeficiency virus) or diabetes. Taking immunosuppressants, which are drugs that are used to intentionally suppress the immune system, is the most common cause of secondary immunodeficiency disorders. These medications are used for many different reasons, including preventing rejection during an organ transplant, suppressing inflammation from rheumatoid arthritis, and treating autoimmune disorders. While these medications are useful for these purposes, they also decrease the body’s ability to fight infections and to destroy cancer cells.

Treating Immunodeficiency Disorders

The treatments for immunodeficiency disorders will vary depending on which type of immunodeficiency you are affected by, as well as what the exact cause of the disorder is. Strategies for preventing and treating the frequent infections include being treated with immunoglobulin, practicing good personal hygiene, not eating undercooked food, not drinking water that may be contaminated, and avoiding any contact with anyone who might have a contagious infection. Antibiotics, antiviral drugs, and vaccines are all treatments that are commonly used for immunodeficiency disorders. Stem cell transplantation is another option that may help to correct some forms of immunodeficiency, especially if it is very severe.

Last Updated: November 23, 2015