Having an Immune Deficiency or Being Immunocompromised

A person is said to have an immune deficiency or be immunocompromised when their immune system is incapable of working at full capacity. It is the opposite of being immunocompetent. The immune system is how the body fights off diseases and protects itself against new infections. Therefore, someone who is immunocompromised will usually get sick more often, stay sick longer, and be more vulnerable to different types of infections.

Conditions Creating Impaired Immunity

There are many conditions that can lead to a person becoming immunocompromised.

Acquired immune deficiency syndrome (AIDS): Part of the definition of AIDS is that people with the disease are immunocompromised. That immune deficiency is one of the signs that separates a person with AIDS from someone who is merely infected with HIV. People with AIDS are susceptible to opportunistic infections that people with healthy immune systems would generally be capable of fighting off. This is because a specific type immune system cells, CD4 cells, are reduced in number when the virus is active. When a person infected with HIV has a CD4 cell count that is below 200 cells per millimeter they are defined as having AIDS.
Chemotherapy: The agents used to attack cancer cells also affect any actively dividing cells, including those in the bone marrow that produce the white blood cells that are a key part of the immune system. White blood cells counts often drop for people undergoing chemotherapy.
Cancer: Certain cancers can cause a person to become immunocompromised even without chemotherapy. These include leukemia and lymphoma, in which cancerous white blood cells crowd out functioning white blood cells.

Autoimmune diseases: These include those in which the immune system attacks itself, such as myasthenia gravis and systemic lupus erythematosus.
Medications: Those that inhibit the immune system include corticosteroids, tumor necrosis factor inhibitors, and anticonvulsants.
Chronic diseases: Diabetes mellitus, kidney disease, hepatitis, and alcoholism can inhibit the immune system.
Congenital disorders: Some rare disorders present at birth affect the immune system and can result in immunodeficiency.
Aging: As you age, you produce fewer T cells, macrophages, and complement proteins, which are all key parts of the immune system.

Being Immunocompromised

Depending on the reason a person is immunocompromised, the deficiencies in their immune system may be temporary or permanent. In many cases, it is possible for a person's immune system to return to nearly full function. If it doesn't, there are therapies available that can help individuals fight off certain infections.

There are also degrees of immune deficiency. Some people simply take longer to fight off common infections, whereas others must be protected from any disease exposures because even a normally mild condition could put their life at risk.

Is Everyone With HIV Immunocompromised?

One of the questions many people have about HIV infection is whether it always leads to someone being immunocompromised. The answer is no. With early and effective treatment, people can live long healthy lives with HIV infection and show no clinical signs of an immune deficiency.