Hyponatremia was observed more frequently in this cohort than has been reported in the initial clinical trials for the two currently available FDA-approved CD19+-directed CAR T-cell therapies, axicabtagene ciloleucel (33% for any grade) and tisagenlecleucel (11% for Na < 130 mEq/L) [11]. Here, CD19 is linked to Hyponatremia.