What Is It?
Immunotherapy refers to treatments that stimulate, enhance or suppress the body's own immune system.
Immunotherapy is also called:
Biological response modifier therapy
Immunotherapy is used to treat certain types of cancer. It is also used to treat inflammatory diseases. 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:
Recruit more immune system cells to attack a tumor
Make cancer cells more vulnerable to an attack by the immune system
Change the way cancer cells grow
Coax cancer cells into behaving more like normal cells
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:
Interferons. Boost the body's immune response. They also can act directly on cancer cells to control their rapid growth.
Interleukins. Stimulate growth of the body's immune cells, especially lymphocytes. Lymphocytes are a type of white blood cell.
Colony stimulating factors (CSFs). Encourage the growth of bone marrow stem cells. Bone-marrow stem cells, especially white blood cells, are needed to fight infections. But they often are destroyed by cancer treatments such as chemotherapy or radiation.
CSFs are used after other cancer therapies. They help to grow a new population of cells in the blood.
Monoclonal antibodies. These are made in a laboratory. They recognize the antigens on the surface of cancer cells.
Monoclonal antibodies can be used alone. Or they can be linked to anti-cancer drugs or to radioactive substances. They can carry these linked poisons directly to tumor cells inside the body.
Some antibodies acting alone can significantly interfere with cancer cells. They can stop them from growing. Or they can cause them to be destroyed by the body's immune system. Monoclonal antibodies spare the body's normal cells.
Monoclonal antibodies also may help people with autoimmune diseases. They target immune cells or chemical messengers involved in inflammation. Monoclonal antibodies may reduce pain and improve joint function in people with rheumatoid arthritis.
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:
Chronic hepatitis B and C
Interleukin-2 (IL-2) may be effective for kidney cancer and advanced melanoma.
Rituximab (Rituxan) is a monoclonal antibody. It is used to treat a type of lymphoma. This treatment is also used for rheumatoid arthritis that is not responding to other agents.
Other monoclonal antibody treatments include:
Abatacept (Orencia) for rheumatoid arthritis
Trastuzumab (Herceptin) for breast cancer
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.
Anti-TNF medications include:
Before treatment with interferon, your doctor will;
Ask if you have a history of heart disease
Ask about medication allergies
Order blood tests, including tests of liver function and levels of various blood cells.
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) is done before treatment with many biological therapies. The screening can be done with a skin test, a blood test and/or a chest X-ray. Your doctor also will ask whether you have had any:
Nervous system diseases
How It's Done
Interferons, adalimumab and etanercept 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.
Usually, the IL-2 and monoclonal antibodies are given intravenously.
Your doctor may use many different tests to monitor the effects of your treatment. These include:
Risks and side effects of biotherapy include:
Redness or infection at the injection site
Flulike symptoms, such as:
Changes in blood pressure
Low levels of white (infection-fighting) blood cells
Infection, including TB, especially in people with prior exposure
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:
Redness or swelling at the injection site
A rash or hives
A tight feeling in your throat
Fever, cough or flulike symptoms
Any other problems that your doctor may warn you about
Also, call your doctor at the first sign of depression. Call even if you think it might just be a passing case of the blues.
National Library of Medicine (NLM)
American Cancer Society (ACS)