Meaning of immunotherapy: Rather than attacking a disease directly, these treatments change what the immune system is willing to attack, or willing to tolerate.

Definition of immunotherapy

Immunotherapy is treatment that works by changing the activity of the immune system rather than acting on a disease directly. In cancer care it aims to restore or strengthen the ability of immune cells to recognize and destroy tumor cells. The same word also names allergen immunotherapy, an unrelated allergy treatment that deliberately reduces immune sensitivity instead of raising it.

How immunotherapy is built

immuno therapy immunotherapy
  • immun/o Combining form · Latin immune, protection
  • -therapy Suffix · Greek treatment

A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.

How does it work against cancer?

Tumors arise from the body's own cells, so the immune system often fails to treat them as foreign, and many tumors actively switch off the immune cells that reach them. Cancer immunotherapy works on that failure rather than on the tumor itself. Some agents release the brakes that hold immune cells back. Others supply immune cells that have been collected, altered or multiplied outside the body and then returned. Others flag tumor cells so that immune cells will attack them, or train the immune system against a target the tumor carries. A few agents work in the opposite direction and are used to soften the immune reaction caused by other cancer treatments.

ApproachWhat it does
Immune checkpoint inhibitorsBlock the off switches tumors use to silence T cells
Cell therapiesReturn altered or expanded immune cells to the body, as in cellular adoptive immunotherapy
Certain monoclonal antibodiesCoat tumor cells so immune cells recognize and destroy them
Cancer vaccines and cytokinesPrompt or amplify a response against a specific target

Why do the side effects look different?

Chemotherapy harms fast dividing tissue, so hair, blood counts and the gut lining take the damage. Immunotherapy instead raises immune activity, and an immune system pushed harder can turn on healthy tissue anywhere. Inflammation of the bowel, thyroid, skin, liver, lungs or joints all occur, sometimes beginning long after treatment starts. Cell therapies can also provoke a sudden storm of immune signaling that causes fever and low blood pressure. The pattern of benefit differs too, since a response may take longer to appear yet last well after treatment ends.

How is allergen immunotherapy different?

It is a separate treatment sharing only the name. A specific allergen is given in small, gradually increasing amounts by injection or under the tongue, over a course lasting years, with the aim of shifting the immune response toward tolerance so that ordinary exposure provokes less reaction. The goal is the reverse of the cancer setting: less immune reactivity rather than more.

Also known as

biological response modifier therapybiological therapybiotherapyBRM therapy

Used in a sentence

Immunotherapy was added to the patient's cancer treatment regimen following surgery.

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Good to know

Cancer immunotherapy and allergen immunotherapy share a name and nothing else, one aimed at strengthening immune activity against tumor cells and the other at reducing immune sensitivity to a specific allergen.

Word origin

Where “immunotherapy” comes from

Formed from immuno-, from Latin immunis, meaning exempt or free from burden, and therapy, from Greek therapeia, meaning treatment.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.