What is Immunosuppression?

The suppression of the body’s innate ability to ward off disease and infection is known as immunosuppression. This suppression may be the result of a disease that targets the immune system, such as the human immunodeficiency virus (HIV), or as a consequence of pharmaceutical agents used to fight certain conditions, like cancer.

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In some cases, immunosuppression may also be deliberately induced. This induction may be necessary for therapeutic interventions, such as tissue and organ transplantation, to reduce the risk of organ rejection.

What are the causes of immunosuppression?

Immunosuppression may be caused by a number of systemic illnesses. These include, but are not limited to the following:

• Diabetes mellitus
• Renal and/or hepatic failure
• Infection of the central nervous system
• Systemic lupus erythematosus
• Rheumatoid arthritis

In addition to systemic illnesses, certain pharmaceuticals and therapeutic interventions can also cause immunosuppression. These include, but are not limited to the following:

• Corticosteroids
• Immunoglobulins
• Antimetabolites
• Biological alkylating agents
• Ionizing radiation

What are the signs and symptoms of immunosuppression?

In general, immunosuppressed patients are typically very ill and susceptible to infection by everyday microorganisms that would otherwise pose no threat to healthy individuals. These are referred to as opportunistic infections, and frequently occur in those with weakened immune systems.

Opportunistic infections may be caused by bacteria, viruses, parasites, and fungi. These microbes easily spread through bodily fluids, the air, or via contaminated food, water, animals and objects. In addition to being physically sick, these patients usually have a wide range of derangements in the parameters of a complete blood count, which are used to indicate an infectious etiology.

Infections in immunosuppressed individuals tend to last longer and are more frequent and difficult to treat than infections in people with normal immune systems. These patients may have more frequent infections of the respiratory and gastrointestinal tracts, as well as inflammation and infection of other internal organs and systems. Moreover, children affected by immunosuppression show signs of abnormal development and growth.  

How is immunosuppression diagnosed and treated?

Immunosuppression may be easily seen from abnormalities in a blood test, particularly white blood cell count and levels of immunoglobulins, which are proteins primarily involved in fighting infections.

Immune system functionality can be ascertained by further tests that check for cellular and humoral immunity. Cellular immunity can be tested with the help of phagocytic function and T cell activation tests, among others. Likewise, humoral immunity can be investigated by employing serum immunoglobulin assays, B cell quantitation, and specific antibody quantitative tests.  

The goal in treating immunosuppression is to target the offending etiology, if possible. It is then important to aggressively treat and prevent infections, while at the same time giving the immune system a boost with pharmacological therapy.

Anti-microbials are of paramount importance against infectious agents. If bacteria are the culprits, then antibiotics are urgently required, and a protracted course of antibiotics is necessary to prevent further infection while the patient’s immune system is still below optimal.

There are several therapies that may be employed when attempting to boost the immunity of an immunosuppressed individual. Once such therapy is the use of immunoglobulins that may be administered as necessary intravenously or subcutaneously.

Other examples of immuno-boosting therapies include the use of interferons and growth factors, which both play roles in the stimulation of immune cells in the fight against pathogens and diseased states.

Further Reading

• All Immunology Content
• What is Immunology?
• Classical Immunology
• Clinical Immunology
• Developmental Immunology

Written by

Dr. Damien Jonas Wilson

Dr. Damien Jonas Wilson is a medical doctor from St. Martin in the Carribean. He was awarded his Medical Degree (MD) from the University of Zagreb Teaching Hospital. His training in general medicine and surgery compliments his degree in biomolecular engineering (BASc.Eng.) from Utrecht, the Netherlands. During this degree, he completed a dissertation in the field of oncology at the Harvard Medical School/ Massachusetts General Hospital. Dr. Wilson currently works in the UK as a medical practitioner.