Immunotherapy is a treatment that stimulates or suppresses your immune system to help your body fight disease or infection.

The field of immunotherapy is rapidly developing as researchers improve their understanding of the immune system’s role in disease. It’s now considered the “fifth pillar” of cancer treatment, along with:

Immunotherapy is used to treat a wide variety of cancers, but it also plays a role in treatment for other conditions, such as:

Keep reading to learn more about immunotherapy, including when it’s used, its types, and potential risks.

The first modern scientific advancement in immunotherapy is often attributed to the German doctors Busch and Fehleisen in the late 1800s. These doctors noticed that tumors regressed after people with cancer were infected with certain types of bacteria, and they later intentionally injected people with cancer with these bacteria to shrink tumors.

In 2018, Dr. James Allison won the Nobel prize for his development of a type of immunotherapy called checkpoint inhibitors, which led to the Food and Drug Administration (FDA)’s approval of ipilimumab in 2011. Since then, immunotherapy research has rapidly been developing.

Much of the current research is focused on immunotherapy for treating cancer, but immunotherapy is used to treat many other conditions as well.


Immunotherapy can enhance your immune system’s ability to find and destroy cancer cells. It’s estimated that every cancer cell has more than 11,000 gene mutations that differentiate them from healthy cells. Some of these mutations make them targets for immunotherapy.

Immunotherapy has been approved or is under investigation for treating many different types of cancer. Some of these include:

Primary immunodeficiencies

Immunotherapy is used to treat some types of primary immunodeficiency. Primary immunodeficiency is a group of more than 200 genetic conditions that impair your immune system.

Some of these conditions include:

  • CTLA4 deficiency
  • LRBAdeficiency
  • leukocyte adhesion deficiency
  • severe combined immunodeficiency
  • X-linked lymphoproliferative disease

According to the Immune Deficiency Foundation, a type of immunotherapy called immunoglobulin replacement therapy is one of the most important and successful therapies for treating primary immunodeficiencies.

Allergic reactions

According to the American College of Allergy, Asthma, & Immunology, immunotherapy is used to prevent allergic reactions caused by substances such as:

  • bee venom
  • dust mites
  • grass pollens

Immunotherapy for these conditions involves injecting gradually increasing doses of the substance you’re allergic to in order to reduce your immune system’s sensitivity to it.

Autoimmune disease

Autoimmune diseases occur when your immune system attacks healthy tissue. The goal of immunotherapy for autoimmune conditions is to block immune activity.

According to the authors of a 2019 editorial, autoimmune diseases should benefit from repurposing immunotherapies developed to treat cancer.

The “Holy Grail” treatment for autoimmune disease is finding a way to selectively treat the autoimmune disease without affecting other immune functions. Currently, control of autoimmune conditions involves taking nonspecific immunotherapy drugs that have a general effect on your immune system and cause side effects.

Tissue and organ transplants

Immunotherapy has long been used to dampen the immune system in people receiving transplanted organs to lower their chances of organ rejection. Usually, drugs are administered in two phases: an induction phase where large doses of immunosuppressants are administered at the time of transplantation and a long-term maintenance phase.

Usually, four types of drugs are given during the maintenance phase:

  • calcineurin inhibitors
  • antiproliferative agents
  • mTOR inhibitors
  • steroids

Inflammatory disorders

Immunotherapy is used to suppress immune factors that lead to inflammation. Immunotherapy is used to treat many types of inflammatory disorders, many of which are also classified as autoimmune disorders.

Examples include:

  • Tocilizumab: Tocilizumab is used for rheumatoid arthritis, juvenile idiopathic arthritis, and adult-onset Still’s disease.
  • Antifrolumab: Antifrolumab is used for systemic lupus erythematosus.
  • Etanercept: Etanercept is used for rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriasis, and psoriatic arthritis.
  • Inebilizumab: Inebilizumab is used for neuromyelitis optica spectrum disorder.

Infectious disease

Research on immunotherapy for treating infectious diseases isn’t as advanced as it is for cancer immunotherapy. Recent advances have been made for treating conditions such as:

Immunotherapy works by either suppressing or stimulating your immune system. Different types of immunotherapies achieve this in different ways.

Five primary types of immunotherapy are used to treat cancer. They are:

  • Immune checkpoint inhibitors: These drugs block your “immune checkpoints,” the part of your immune system that limits it from being too aggressive.
  • T-cell transfer therapy: This therapy increases the ability of T cells to recognize cancer. T cells are a type of white blood cell that play an important role in your adaptive immune system.
  • Monoclonal antibodies: These medications contain proteins that bind to cancer cells to signal for your immune system to destroy them.
  • Treatment vaccines: These vaccines stimulate a stronger immune reaction against cancer cells.
  • Immune system modulators: These medications enhance part or all of your immune system.

Other types of immune therapy include:

  • Allergen shots: Allergen shots contain a small amount of an allergen to help your body produce antibodies to the substance and reduce your allergy symptoms.
  • Intravenous (IV) immunoglobulin therapy: This is a therapy where antibodies from donors are injected through an IV line to treat some inflammatory and autoimmune conditions.
  • Immunosuppressive drugs: These drugs suppress your immune system activity to manage some autoimmune conditions and prevent organ rejection in people who receive transplants.
  • Helminth therapy: This is an experimental treatment that involves administering helminth parasites to treat some autoimmune and inflammatory conditions. It’s not FDA approved at this time.
  • Transfer factors: Transfer factors are proteins produced inside your immune system. They’re under investigation for treating conditions such as herpes, yeast infections, and AIDS.
  • Immunization: Vaccines prevent infections by teaching your immune system to recognize certain infections. Many vaccines have been developed to treat conditions such as:

Immunotherapy is an effective treatment for many different conditions and is still under investigation for many others.

It’s highly effective for treating some types of cancer caused by viruses. Some viruses linked to cancer include:

In a 2019 review of studies, researchers found convincing evidence to support:

Research suggests that allergy shots may potentially decrease symptoms of many allergies. Effectiveness seems to be linked to the dose and time of treatment.

Side effects vary by treatment and can vary from mild to life-threatening. Some side effects include:

Other side effects not on this list can also occur. A doctor or healthcare professional can give you the best idea of what to expect for your type of treatment.

A doctor may recommend immunotherapy if you have cancer or another condition that immunotherapy is approved to treat. Immunotherapy is worth considering if research has found that immunotherapy is linked to better outcomes for your condition. A doctor can help you decide whether the benefits outweigh the risks of side effects and the cost.

A doctor may recommend against immunotherapy if you have certain health concerns. For example, doctors are often hesitant to prescribe immunotherapy for cancer treatment in people with autoimmune diseases.

Immunotherapy is a type of therapy that stimulates or suppresses the activity of your immune system. Immunotherapy research is rapidly advancing. It’s used to treat many different types of cancer and other conditions such as autoimmune diseases, allergic reactions, and infectious diseases.

A doctor can help you figure out if you might benefit from immunotherapy. They can also advise you about any clinical trials examining immunotherapy for treating your condition.