What is cytokine release syndrome?

Cytokine release syndrome is a serious side effect that can happen with CAR T-cell therapy.

It is caused when the transferred T cells, or other immune cells responding to the new T cells, release a large amount of cytokines into the blood. Cytokines are immune substances that have many different functions in the body.

A sudden increase in cytokine levels can cause:

• fever
• nausea
• headache
• rash
• rapid heartbeat
• low blood pressure
• trouble breathing

Most people have a mild form of cytokine release syndrome, but in some people it may be severe or life-threatening. Because of this, your care team will watch you closely after treatment. Tell them right away if you notice any of these symptoms so they can act quickly.