Your immune system is a complex network of tissues, cells, and proteins. All of these work together to protect you from things such as disease-causing germs, cancer cells, and potentially harmful substances in the environment.

Some drugs affect the immune system to treat a disease or illness. These are referred to as immunomodulators.

The types of immunomodulators and the conditions that they can treat are very diverse. Keep reading to learn more about immunomodulators, how they work, and what they’re used for.

An immunomodulator is a substance that modifies, or modulates, the immune system to help your body respond to a disease or illness.

Different immunomodulators can affect different parts of the immune system. Some types act very broadly, while others only target very specific pathways.

Immunomodulators can also take many different forms. Some may be relatively small molecules, while others may take the form of larger proteins such as monoclonal antibodies.

Generally speaking, immunomodulators can work in one of two ways. They can either stimulate or suppress the immune system.

When an immunomodulator stimulates, it gives your immune system the boost it needs to help it respond to an illness or disease. Immunomodulators used in cancer treatments can work this way.

Immunosuppressants are immunomodulators that lower immune system activity. These types of immunomodulators are used when the immune system is contributing to disease such as in autoimmune disorders.

Immunomodulators are used for many different types of illnesses and diseases. These include:

Immunomodulators come in many different forms. Let’s look at these now.

Immunotherapy for cancer

Immunotherapy is a type of cancer treatment that helps your immune system to better respond to cancer. In this situation, immunomodulators are boosting the activity of the immune system.

Some examples of cancer immunotherapy include:

  • Immune checkpoint inhibitors: Immune checkpoint inhibitors work by turning off signals that prevent immune cells from responding to cancer cells.
  • Cytokines: Cytokines are small proteins that are involved in immune system signaling.
  • Immunomodulating agents: These are groups of drugs such as thalidomide and lenalidomide that target immune pathways. They’re typically used for cancers such as multiple myeloma.
  • Chimeric antigen receptor (CAR) T-cell therapy: CAR T-cell therapy extracts immune cells called T cells from your blood. These cells are then modified in a lab so that they specifically respond to cancer.
  • Cancer vaccines: Cancer vaccines stimulate the immune system to respond to cancer. There are cancer vaccines available for melanoma and prostate cancer.

Traditional immunosuppressants

Traditional immunosuppressants are drugs that work to broadly dampen the immune response. They’re typically used for autoimmune disorders in which the immune system is mistakenly attacking healthy tissue.

Some examples of traditional immunosuppressants are:


Biologics are proteins that are produced in a laboratory and target specific pathways of the immune response, typically those that are involved in inflammation.

Biologics are used for conditions that are mediated by increased inflammation. Because they only suppress certain parts of the immune response, their effects aren’t as broad as those of traditional immunosuppressants.

Some examples of biologic drugs are:

Disease-modifying therapies for MS

MS is treated with disease-modifying therapies (DMTs). These drugs help to lower levels of inflammation, thereby lowering the likelihood of relapses and preventing additional damage to myelin and the nerves under it.

There are many DMTs that can be used for MS. Some include:


Corticosteroids are similar to naturally occurring steroid hormones in your body. They have immunosuppressive and anti-inflammatory activities and can be used in the treatment of a variety of different conditions such as:

Some examples of corticosteroids are:

Immunomodulators can be given in many different ways. How they’re administered depends on the specific drug that’s being used and what it’s being used to treat. Some of the most common ways include:

Some types of corticosteroids can also be applied directly to the skin as a cream or ointment. This is called topical application.

If you’ve be prescribed an immunomodulator, a doctor or healthcare professional will give you detailed information about how and when you need to take your medication. Be sure to follow these instructions carefully.

The effectiveness of an immunomodulator can depend on the specific immunomodulator and the condition that it’s being used to treat. Let’s look at what a handful of research says for some immunomodulators.

Immunomodulators in RA

Methotrexate is one of the initial treatments that’s started in people with RA. Biologics are typically used when methotrexate alone isn’t effective at managing the condition.

An older 2010 review compared methotrexate with biologics. It notes that methotrexate and biologics were similarly effective when it came to treatment response. There was less time to improvement and greater inhibition of disease progression with biologics

A more recent 2019 review found that combination therapy was more effective. Using methotrexate with a biologic led to improved disease management, remission, and functional ability compared with when either type of therapy was used alone.

Immunomodulators in MS

In the treatment of MS, some DMTs are more effective than others. These are called high-efficacy DMTs and include DMTs such as natalizumab (Tysabri) and fingolimod (Gilenya).

High-efficacy DMTs more effectively treat MS but are associated with an increased risk of serious side effects compared with other DMTs. Despite this, early treatment with high-efficacy DMTs can be very beneficial.

A 2021 study found that in comparison with moderate-efficacy DMTs, people who used high-efficacy DMTs as their first MS medication were 3.9 times more likely to have no evidence of disease activity within the first year.

Many types of immunomodulators are geared toward suppressing immune system activity. While this can be beneficial for treating many diseases and conditions, it can also lead to a weakened immune system.

People with a weakened immune system are at an increased risk of contracting infections. As such, if you’re taking an immunosuppressive medication, it’s important to take steps to lower your risk of getting an infection such as:

  • staying up to date on recommended vaccines
  • avoiding contact with people who are currently sick
  • washing your hands regularly with soap and water
  • not sharing personal items or eating utensils with others
  • frequently cleaning high-touch surfaces in your home

Immunomodulators can also cause a variety of other side effects as well. Some examples can include:

Individual drugs can be associated with more specific types of side effects. If a doctor prescribes an immunomodulator, be sure to ask about its specific side effects and what you can do to manage them, should they occur.

Can you take immunomodulators if you’re pregnant or breastfeeding?

According to the American College of Obstetricians and Gynecologists, many commonly prescribed immunomodulating drugs can be used safely during pregnancy or breastfeeding under the supervision of a doctor.

Some immunomodulating drugs, such as methotrexate and leflunomide, can be harmful to a developing fetus and shouldn’t be taken during pregnancy or breastfeeding.

It’s important to discuss your medications with a doctor if you’re pregnant, planning to become pregnant, or are breastfeeding.

Is there anyone who shouldn’t take immunomodulators?

People with an allergy to a particular immunomodulator should avoid taking it. You may also need to avoid taking immunomodulating drugs if you have an active infection.

Some immunomodulators may cause serious side effects in people with specific health conditions. Additionally, immunomodulators can potentially interact with other medications or supplements that you take.

As such, always discuss your health and medication history with a doctor prior to starting on an immunomodulator.

Is it OK to have vaccines if you’re on immunomodulators?

It’s OK to have inactivated vaccines while on immunomodulators, specifically immunosuppressants. Some examples of inactivated vaccines include the COVID-19 vaccine, flu shot, and the HPV vaccine.

Live vaccines, such as the MMR vaccine and the chickenpox vaccine, can cause potentially serious problems for people with a weakened immune system and should be avoided while taking immunosuppressants.

Does the human body have natural immunomodulators?

Yes. You have proteins in your body called cytokines that regulate your immune response. When a receptor on the surface of a cell interacts with a cytokine, the cell’s behavior can change based on the type of cytokine it’s interfacing with.

Are immunomodulators used to treat COVID-19?

Yes. The COVID-19 treatment guidelines developed by the National Institutes of Health recommend the use of some immunomodulatory drugs to treat COVID-19 in some cases.

Immunomodulators are used in the event of serious illness where there’s widespread inflammation in the body and supplemental oxygen is needed. They can include:

  • dexamethasone, a corticosteroid
  • baricitinib (Olumiant), a biologic
  • tocilizumab (Actemra), a biologic

Immunomodulators are substances that influence the activity of the immune system in some way. Generally speaking, they can either stimulate the immune system or suppress it.

A doctor may prescribe you an immunomodulator for a variety of different conditions. These drugs can be used in the treatment of things such as cancer, autoimmune disorders, and infections.

Each individual immunomodulator is different in terms of how it’s taken, its side effects, and its effectiveness. If you’re prescribed an immunomodulator, be sure to cover these topics with a doctor prior to starting on your new medication.