Definition of Cytokine Storm

Cytokine storm is a severe reaction by the body's immune system in which too many cytokines (substances that serve as messengers to coordinate and direct the immune system) are released into the circulation in a short time. Causes can include infections, autoimmune conditions, or other diseases. Cytokine storm is also a possible side effect of some kinds of immune therapy, including CAR-T cell therapy. Signs and symptoms of cytokine storm include high fever, skin redness, swelling, nausea, and fatigue. In severe cases, a cytokine storm may be life-threatening. It is also known as hypercytokinemia.