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Medically reviewed by Last updated on Jan 2, 2024.

What is Immunotherapy?

Harvard Health Publishing

Immunotherapy refers to treatments that stimulate, enhance or suppress the body's own immune system.  

Immunotherapy is also called: 

Immunotherapy is used to treat certain types of cancer. It is also used to treat inflammatory diseases, such as. These include: 

Our body's immune system recognizes cancer cells as foreign or abnormal. Unlike normal cells, cancer cells have unique proteins (antigens) on their outer surface. Antibodies are proteins produced by the immune system. They latch onto the cancer cells' antigens. In this way, they label or tag the abnormal cells.  

Ideally, special cells in the immune system would be recruited to destroy the tagged cancer cells. Sometimes, however, the immune system needs some help. 

Biological therapy helps to stimulate the immune system to fight cancer. The chemicals used in immunotherapy often are called biological response modifiers. They enhance the body's normal immune-system reaction to a cancer threat.  

Some biological response modifiers are chemicals that occur naturally in the body. But they are produced in larger amounts in a laboratory to help boost a person's immune response.  

Biological response modifiers can play many different roles in fighting cancer. For example, they can:  

Immunotherapy also can be used to suppress the immune system. This is particularly helpful in autoimmune disorders. In these disorders, the immune system "misfires." It wrongly attacks normal tissues.  

Inflammation is useful for fighting infection. But in autoimmune diseases, it damages normal tissues. Biological therapies can cool off this harmful inflammation.  

Examples of biological therapies currently in use include:  

What It's Used For

Different biological response modifiers are currently being used against many different types of cancer.  

Interferons have been used to treat: 

Interleukin-2 (IL-2) may be effective for kidney cancer and advanced melanoma.  

Rituximab (Rituxan) is a monoclonal antibody. It is used to treat non-Hodgkin's lymphoma and chronic lymphocytic leukemia. This treatment is also used for autoimmune and inflammatory conditions, such as rheumatoid arthritis, that are not responding to other agents.  

Other examples of monoclonal antibody treatments include: 

Anti-TNF therapy inhibits the production of tumor necrosis factor. It is one of the most effective treatments for rheumatoid arthritis, inflammatory bowel disease and other inflammatory diseases when conventional drugs fail.  

Examples of some anti-TNF medications include: 


Before treatment with interferon, your doctor will; 

Your doctor also will ask about any history of depression or other psychiatric problems. Interferon has been associated with an increased risk of depression and possibly suicide. 

Screening for exposure to tuberculosis (TB) and chronic hepatitis is done before treatment with many biological therapies. Your doctor also will ask whether you have had any: 

How It's Done

Some immunotherapies require visiting a health center for intravenous (IV) infusions, while many others are given by injection. A medical professional will show you how to prepare the needle and syringe. You will be taught how to inject yourself.  

A family member or other caregiver can learn the injection technique as well. He or she can give you the injection if you feel too weak or ill to give it to yourself. 


Your doctor may use many different tests to monitor the effects of your treatment. These include: 


Risks and side effects of biotherapy include: 

Interferons may be associated with depression and suicidal thoughts.  

Trastuzumab (Herceptin) can cause the heart to pump less vigorously leading to heart failure. Usually heart function will improve when the drug is stopped.  

When To Call a Professional

Call your doctor immediately if you develop:  

Additional Info

American Cancer Society (ACS)

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.