The following patients were not described in the table because of insufficient information: patient 15, patient with PMBL who received an ICI as bridging therapy and who developed acute and irreversible paraplegia at day +7 after axi-cel²⁰; patient 16, patient with PMBL who died 2 months after axi-cel infusion from acute encephalitis and myelitis²¹; patient 17, 40-year-old woman with DLBCL who developed acute myelopathy at day+10 after infusion of unspecified CAR T cells and who was treated with tocilizumab and steroids and regained function⁷; patient 18, patient with large B-cell lymphoma who received a fully human scFv containing, CD19-directed CAR T-cell therapy (JCAR021) and who subsequently developed paraplegia associated with spinal cord edema^22,23; patients 19 and 20, active cases with large B-cell lymphomas who developed acute myelitis after CD19-directed CAR T-cell therapy (not published). All patients, except patient number 2 with relapsed disease, had primary refractory disease before CAR T-cell infusion. Disease status was not reported for patient number 3. Only patient number 4 had CNS involvement at CAR T-cell infusion. No patient received CAR T-cell therapy before the treatment indicated in this table. None of the patients have been reported to develop IEC-HS (immune effector cell–associated hemophagocytic lymphohistiocytosis-like syndrome). However, because of a lack of data, we cannot exclude the possibility that some cases were associated with this complication.

ASCT, autologous stem cell transplant; Axi-cel, axicabtagene ciloleucel; BEAM, carmustine, etoposide, cytarabine (Ara C) , and melphalan; Brexu-cel, brexucabtagene autoleucel; CR, complete remission; CYVE, cytarabine andetoposide; DA-EPOCH-R, dose-adjusted etoposide, prednison,e vincristine (oncovin), cyclophosphamide, doxorubicin (hydroxydaunorubicin), and rituximab; EBV, Epstein-Barr virus; GDP, gemcitabine, dexamethasone, and cisplatin; HD-MTX, high-dose methotrexate; Hyper-CVAD, hyperfractionated cyclophosphamide, vincristine, doxorubicin (adriamycin), and dexamethasone; LA, last assessment; LE, lower extremity; Max, maximum; MCL, mantle cell lymphoma; MP, methylprednisolone; N/A, not applicable; Not reported, no information provided on the occurrence; not specified, occurred but no details provided; R-CHOP, rituximab, cyclophosphamide, doxorubicin (hydroxydaunomycin), vincristine (oncovin), and prednisone; R-ESHAP, rituximab, etoposide, methylprednisolone (solu-medrol), high-dose cytarabine (Ara C), and cisplatin (platinol); R-ICE, rituximab, ifosfamide, carboplatin,and etoposide; scFv, single-chain variable fragments; tisa-cel, tisagenlecleucel.

The ICANS grade was defined according to the American Society for Transplantation and Cellular Therapy (ASTCT) consensus grading. According to this definition, deep focal motor weakness, such as hemiparesis or paraparesis, is classified as grade 4.