Investigators are testing the “fatal toxicities” question behind autoimmune CAR T safety assumptions, with developers pointing to manufacturing speed, construct design, and patient biology as possible drivers of IEC-HS risk. The coverage highlights how teams that aim to avoid severe autoimmune complications are still grappling with identifying which biologic and operational factors most influence risk. The debate is centered on how to predict and prevent immune-mediated events that can become life-threatening after CAR T therapy, rather than relying solely on broad safety theses. With CAR T moving earlier in disease and expanding target formats, the field is under pressure to tighten risk management frameworks. Regulators and clinicians are likely to keep demanding more granular safety characterizations as different CAR T constructs and manufacturing workflows expand across indications.