Learning About Cytokine Release Syndrome (CRS)

Cytokine release syndrome (CRS) is an inflammatory response that can start quickly and affect the whole body. A variety of factors can cause it, including infections and certain drugs. CRS can occur after some types of immunotherapy treatments, such as chimeric antigen receptor (CAR) T-cell therapy.

When immune cells are affected by immunotherapy, the cells may quickly release a large amount of cytokines into the blood. Cytokines are small signaling proteins. They often act as messengers between cells. The rapid release of these proteins can cause an inflammatory response in the body.

CRS is graded from 1 (mild) to 4 (life-threatening) based on how severe the symptoms are. How mild or severe CRS is depends on factors such as the type of therapy that was used and the disease that is being treated.

Most cases of CRS are mild, but some can be more severe. Symptoms may include:

• Mild, flu-like symptoms.
• Fever.
• Chills.
• Dizziness.
• Fatigue.
• Headache.
• Rash.
• Joint or muscle pain.

Some people may have serious complications. Examples are problems with the kidneys, liver, or lungs, low blood pressure, or heart problems. These can be life-threatening. Talk to your care team about what you should watch for. Ask when you need to report them to your care team.

Your doctor will ask about your health history and do a physical exam. You may need to have some tests, such as blood tests. These are done to check organ function and look for inflammation. Your doctor may have you do other lab tests and imaging tests. These are to make sure your symptoms are not caused by another infection.

Treatment will depend on the type of immunotherapy that you were given. It will also depend on how severe your CRS is. For more mild cases, medicines may be used to treat the symptoms. These may include medicines that reduce fever and swelling. You may also get intravenous (I.V.) fluids. Severe CRS may be treated with oxygen therapy or ventilation. You may also need to take medicine for low blood pressure and other medicines that reduce inflammation and target cytokines.