Immune Effector Cell-associated Hemophagocytic Syndrome (IEC-HS) as a late immune-mediated toxicity after CAR-T therapy in Diffuse Large B-Cell Lymphoma (DLBCL): a case report.

Chimeric antigen receptor (CAR) T-cell therapy has dramatically improved the prognosis of patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) [1,2]. However, immune-mediated toxicities represent a significant emerging clinical challenge, particularly those with late onset or uncommon presentations. We report the case of a 71-year-old woman with heavily pretreated DLBCL who developed immune effector cell-associated hemophagocytic syndrome (IEC-HS) with a fatal outcome six months following CAR-T infusion. This case highlights the occurrence of late -onset CAR-T-related toxicities and the potential role of CAR-T cell persistence in sustaining dysregulated immune activation.