Abstract: Objective To further study the diagnosis and treatment of CAR-T cell-related encephalopathy syndrome (CRES）and cytokine release syndrome (CRS), we reviewed two cases of CRES and CRS retrospectively. Methods Clinic data of two patients with relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) after treated by CAR-T cell immunotherapy were analyzed combined with review of literature. Results Both of the two patients developed severe CRS (Grade 3) and CRES (Grade 3) .They were both developed epilepsy, hyperpyrexia, hypotension, hypoxia, tachycardia, and coagulation disorders. The level of C-reactive protein (CRP), Serum ferritin (SF), Interleukin (IL)-2, IL-6 and IL-10 were significant increased. The timing of onset for CRS were the 2th or 7th day after CAR-T cell transfusion, while CRES were 4th or 10th day, respectively. The first patient was treated with tocilizumab (8 mg/kg) and dexamethasone (20 mg/d), then clinical symptoms were obviously alleviated. The second patient was treated with tocilizumab (8 mg/kg) and dexamethasone (20mg/d), but still developed CRES, so switch to methylprednisolone (1 g/d), then the clinical symptoms were obviously alleviated. All of the two patients appeared to make a full recovery. Conclusion Monitoring of toxicities after CAR-T cell therapy and quick management of CRS and CRES are helpful for improvement of a clinical efficacy and safety in the treatment of CRES for patients with R/R B-ALL treated by CAR-T cell immunotherapy.

Key words: Chimeric, antigen, receptor, T, cells, Tocilizumab, Cytokine, release, syndrome, CAR-T, cell-related, encephalopathy, syndrome, Acute, lymphoblastic, leukemia