Cytokine Release Syndrome Biology and Management

The successful application of chimeric antigen receptor (CAR) T cells for the treatment of relapsed and refractory B-cell malignancies has ushered in a new frontier for the immunotherapy of cancer. Despite its successes, CAR T-cell therapy presents several challenges. Cytokine release syndrome (CRS) triggered by robust and exponential CAR T-cell expansion is the most common adverse effect and may be severe or life-threatening. Although modulation of the interleukin 6 axis was appreciated early on as a means to manage CRS, the exact underlying mechanisms leading to severe CRS remain to be elucidated. What is clear is that severe CRS involves recruitment of the broader immune system into a hyperinflammatory and unregulated state. Myeloid-derived cells appear to play a critical role in this regard and are at the center of active investigation. In this article, we will focus on important elements of CRS, the clinical manifestations, underlying biology, and management strategies including grading, supportive care, and treatment via immunosuppression.