Very unusual extremely high ferritin with cytokine release syndrome in a patient with hematological malignancy after experimental chimeric antigen receptor (CAR)-T-Cell therapy.

BACKGROUND: Chimeric antigen receptor (CAR) T cell therapy is an immunotherapy that has resulted in tremendous progress in the treatment of patients with B cell malignancies. However, significant toxicities may also be associated with such therapy. Here we report extremely high ferritin in a male patient after such therapy.

CASE PRESENTATION: We present a case of a 52 year old male with a history of B-cell acute lymphoblastic leukemia who received chimeric antigen receptor T-cell (CAR-T) therapy with rapcabtagene autoleucel (carvykti). The patient subsequently developed cytokine release syndrome (CRS) which during its resolution results in a hemophagocytic lymphohistiocytosis (HLH)-like syndrome that fell short of being diagnostic. This syndrome tracked closely with the onset and resolution of immune-effector cell-associated neurotoxicity syndrome (ICANS), with close correlation between the severity of laboratory abnormalities, particularly extremely high ferritin (peak value: 81,540 μg/L), and clinical encephalopathy.

CONCLUSIONS: Cytokine release syndrome after experimental (CAR) T cell therapy may cause extremely elevated ferritin and hemophagocytic lymphohistiocytosis -like syndrome.