Your immune system's job is to protect you from illness and any foreign substances that it sees as a threat to your health.
Scientists have found a way to use the body's immune system to help treat or defend against a number of health problems. This treatment is known as immunotherapy.
Immunotherapy is considered a type of biotherapy, also called biologic therapy. It uses and stimulates the body's natural processes to protect health by encouraging and improving these functions. Immunotherapy also boosts the immune system by using synthetic (made in a lab) proteins that work like those naturally produced by the immune system.
The body develops immunity–or protection–against harmful substances and diseases as a result of exposure to them. Immunity is either active or passive, depending on the means of exposure to the substance identified by the body as harmful.
Active immunity, also called natural immunity, develops when your body is exposed to a germ or a disease and your immune system makes antibodies to combat that specific germ or disease. This process can also happen after a vaccination.
Passive immunity means that the antibodies that fight a certain disease or germ are made in a lab and introduced to your body, rather than made by your immune system. Passive immunity offers short-term protection right away, while active immunity offers longer-term protection that takes weeks to develop and may last a lifetime.
It's thought that the body's immune system can be manipulated to fight disease, including cancer. The immune system doesn't naturally attack cancer because it sees cancer cells as normal rather than harmful. The cancer cells are too much like the body's healthy cells, so the immune system doesn't even try to destroy them. Still, there are ways to use the immune system to help fight cancer.
In the 1800s, a doctor noticed that patients with cancer who developed infections fared better than cancer patients who didn't, perhaps because the infections kicked the immune system into gear. He even started exposing cancer patients to certain bacteria, which did help some of them. With the development of radiation therapy and chemotherapy, this treatment fell out of favor. But researchers are once again investigating the use of immunotherapy to treat cancer.
Immunotherapy may be used to:
Treat or manage cancer. Some of the research being done in the field of immunotherapy is studying how well it works to treat cancer. Immunotherapy is sometimes used along with other treatments to help them work better. Immunotherapy works best to treat early-stage cancers. It is not as good at treating late-stage cancers that have spread throughout the body.
Prevent cancer. Today, immunotherapy as a vaccine to prevent cancer is still in the experimental stages. Vaccines typically involve using destroyed or weakened versions of bacteria and viruses to encourage the immune system to attack those foreign substances. This, in turn, prevents illness when the body is exposed to live versions of those same bacteria or viruses. Cancer vaccines available today help to protect against the viruses that can lead to cancer, such as the human papillomavirus, or HPV, which causes cervical cancer and many other types of cancer. Researchers still have a lot of work to do to use immunotherapy as a true vaccine to prevent cancer.
Control asthma and allergy symptoms. Immunotherapy shots are often given to people with severe allergies or asthma to help them become less sensitive to allergens and reduce symptoms. It first exposes the body to small amounts of an allergen. Then it slowly increases the dose to encourage the immune system to build up a tolerance to that allergen. This results in fewer symptoms. Immunotherapy shots also reduce airway inflammation in people with asthma, which helps provide better management of asthma symptoms.
Medical research and advances continue as doctors try to better understand how the immune system works and how they can use immunotherapy to prevent and/or manage certain diseases and chronic conditions.