Immunotherapy is a form of treatment that can activate the body’s immune system. Doctors can use it to prevent organ transplant rejection and treat conditions that affect the immune system.

Immunotherapy can help people with weakened or overactive immune systems by controlling the immune system response.

Immunotherapy can also help prevent organ rejection in people who have received an organ transplant.

Read on to learn more about immunotherapy, including its different types and which conditions it can treat.

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The immune system helps the body fight off invading pathogens such as viruses or bacteria. Some people have weakened or overactive immune systems that do not work as they should.

Immunotherapy is a form of treatment that can support a person’s immune system to help it heal itself from certain conditions, such as cancer.

Immunotherapy treatment is available in many forms, such as:

  • medications
  • vitamins and minerals
  • biological medicines
  • immunizations

Immunotherapy can help treat many conditions, including:


Cancer occurs when cells divide uncontrollably and abnormally. Immunotherapy can help the immune system fight and destroy cancer cells.

Learn about immunotherapy for lung cancer.

Primary immunodeficiencies

Primary immunodeficiencies, or primary immune deficiency diseases (PIDDs), are rare conditions that inhibit a person’s immune response. PIDDs can increase a person’s risk of severe infections or cancer.

Allergic reactions

Allergic reactions occur when a person’s immune system overreacts to certain substances, such as:

  • pollen
  • particular foods
  • pet hair

Autoimmune conditions

Autoimmune conditions occur when a person’s immune system mistakenly attacks healthy tissue.

Some examples of autoimmune conditions are:

Tissue and organ transplants

People with certain health conditions may need an organ or tissue transplant. When a person receives a donor organ, their immune system may treat it as foreign tissue.

If this occurs, the body may reject the transplant and attempt to destroy the transplanted tissue.

Inflammatory disorders

Inflammatory disorders occur when the immune system attacks healthy tissue, causing inflammation.

IBD, arthritis, and gout are inflammatory disorders.


Infections occur when bacteria, viruses, or other microbes multiply inside a person’s body.

These organisms can infect a person through cuts, coughs, sneezes, or contaminated food.

Immunotherapy can help support a person’s immune system.

When a person has an immune response, their immune system creates additional white blood cells to target invading organisms.

A condition that weakens the immune system can result in fewer white blood cells than necessary to fight off invading pathogens, making it more difficult for the body to fight infections.

Immunotherapy can support a person’s immune response by supplying the person with more white blood cells or helping the immune system recognize invading pathogens.

Learn how effective immunotherapy can be for ovarian cancer.

There are many types of immunotherapy and medications that affect the immune system, such as:

  • Immune checkpoint inhibitors: These medications help the immune system recognize cancer cells.
  • CAR T-cell therapy: This treatment removes some of a person’s T cells (a type of white blood cell) and mixes them with a virus. The virus helps the T cells learn how to attach to tumor cells, allowing them to find and kill cancer cells.
  • Monoclonal antibodies (mAbs or MoAbs): These are synthetic versions of antibodies that can target cancer cells.
  • Treatment vaccines: Treatment vaccines help strengthen the immune systems of people who have cancer.
  • Immunomodulators: Immunomodulators are a type of drug that can boost specific parts of the immune system, helping to treat certain kinds of cancer.
  • Allergen shots: Allergen shots help desensitize the immune system to certain substances.
  • Intravenous immunoglobulin therapy (IVIG): IVIG increases the number of antibodies in a person’s blood.
  • Immunization: Immunization involves vaccinating a person against certain diseases. This prepares the immune system to respond more efficiently when it encounters specific pathogens.

Immunotherapies vary in terms of effectiveness. Specific immunotherapies may be more effective than others for certain health conditions.

People should consult a doctor to find out what kind of immunotherapy might be best for them.

For example, a 2020 review found that 22% of people with advanced melanoma who received ipilimumab, a type of mAb, lived for an additional 3 years or more.

Learn about immunotherapy vs. chemotherapy.

Immunotherapy can cause side effects, which vary depending on the type of immunotherapy a person receives.

Some of the most common side effects of immunotherapy are:

Severe side effects of immunotherapy can include:

If someone experiences any of these side effects, they should seek immediate medical attention.

The suitability of immunotherapy as a treatment option varies from person to person.

For example, people with cancer cells that contain large amounts of the protein PDL1 may benefit from immunotherapy.

And according to the National Heart, Lung, and Blood Institute, allergy shots may be useful for people with mild to moderate asthma that has not responded to other treatments.

A person should talk with a doctor to find out whether immunotherapy is an option for their unique case.

Immunotherapy can help support or suppress a person’s immune system and may help treat certain conditions.

However, this type of treatment may not be beneficial for everyone.

People should consult a doctor to discuss whether immunotherapy is an option for them.