Immune System Suppressors

Since there is no cure for Crohn’s disease, symptom relief comes in the form of remission. While a variety of treatments are available that can help ease a patient’s symptoms, immunomodulators suppress the body’s immune system. For someone with Crohn's, this can help reduce the swelling that exacerbates so many symptoms.

Immunomodulators include immunosuppressants and immunostimulants.   Immunosuppressants inhibit the body’s immunity, but immunity suppression can also put the body at higher risk for cancers and other diseases.

Immunostimulants increase or “stimulate” the body’s immune system, which encourages the body to begin fighting illness.

There are various types of immunomodulators, each sold under its own brand name. Azathioprines, mercaptopurine, and methotrexate are the three main types.


Known by the names Azasan or Imuran, azathioprine is often used in transplant patients to prevent the body from rejecting the new organ by suppressing the body’s immune system. It also helps with rheumatoid arthritis, where a patient’s body begins attacking its own joints.

In Crohn's patients, azathioprine has been found to reduce the risk of recurrence over a six month to two-year period. Research has also shown that azathioprine may reduce the need for steroid treatment, which causes uncomfortable side effects. However, the long-term effects have not yet been proven in research. There are also some rare, but severe side effects of azathioprine..

Side effects include the halted production of white blood cells, which can cause problems since white blood cells fight infection. Patients taking azathioprine may also experience an inflammation of the pancreas or a higher risk of lymphoma. Because of this, azathioprine may be prescribed for more severe cases of Crohn's, and patients are advised to consider all of the risks before taking azathioprine.


?Generally used to treat leukemia, mercaptopurine—sold under the brand name Purinethol—is known to stop cancer cells from growing. In Crohn's patients, mercaptopurine, like azathioprine, can induce remission, which is the goal since no permanent cure is available.

Because mercaptopurine can reduce the production of white and red blood cells, your physician will likely want to conduct regular blood tests to ensure there is no damage to your bone marrow. Patients may also be tested for TPMT deficiency, which is an enzyme deficiency that could decrease the number of cells responsible for providing immunity.

Other side effects of mercaptopurine can include mouth sores, fever, sore throat, and blood in the urine or stools. As with azathioprine, a Crohn's patient will likely want to consider these side effects before beginning treatment.


Sold under the brand name Trexall, methotrexate blocks cell metabolism, leading to its use for Crohn's Disease, cancer, and psoriasis. However, methotrexate has side effects that include possible toxicity of the liver or bone marrow and, rarely, toxicity of the lungs. Less severe side effects include headache, drowsiness, and skin rash, among others.


Levamisole is an immunostimulant that helps the body’s natural immune system fight disease. It is often used in cancer patients, but in trials some success has been made with Crohn's disease. Levamisole, however, was found in one trial to cause severe acute deterioration of joints in one patient. The condition corrected itself within a few months, but it still should be noted. In another trial, two patients developed a form of temporary arthritis that resolved.

BCG Vaccine

Known for its use against tuberculosis, the BCG vaccine may also be used in the treatment of Crohn's Disease. While the BCG vaccine has had some success in trials with Crohn's patients, side effects can include diarrhea and nausea. By lowering the dosage, side effects seemed to diminish.

Things to Keep in Mind

While immunomodulators can help combat symptoms related to Crohn's disease, the general side effect is that they interfere with your body’s ?ability to fight infection. While taking immunomodulators, pay attention to any sudden rise in body temperature and, if you find yourself chilled or suffering from fever, contact your doctor immediately.

Any time you are taking immunomodulators, be sure to get your blood  tested regularly for signs of damage to your bones and internal organs.

?While all immunomodulators may not be bad to take during pregnancy, if you are either pregnant or may become pregnant, you need to speak with your doctor. Methotrexate can cause loss of pregnancy or birth defects if a patient becomes pregnant while taking it. This applies to both men and women participating in conception.