One patient developed grade 3 CAR-T cell-related encephalopathy syndrome (CRES) on day 33 after infusion, with clinical manifestations of cognitive impairment, aphonia, unresponsiveness, mild irritability and headache, febrile neutropenia, hypogammaglobulinemia (decreased by 0.71-fold), and upper respiratory tract infection, but not accompanied by abnormal elevations of CRP or IL-6. Here, IL6 is linked to Cognitive impairment.