Recently, Teachey et al. performed a screen for biomarkers in patients after CAR T cell therapy for ALL and found that peak levels of IL-6, soluble IL-6 receptor, IFN-γ, and sgp130 correlated with the risk of severe CRS in a cohort of 35 pediatric and adult B-ALL patients receiving CD19-CAR T cell therapy. The gene discussed is CD19; the disease is acute lymphoblastic leukemia.