CAR-T Following ASCT for Relapsed/Refractory B-Cell Non-Hodgkin's Lymphoma (R/R B-NHL) With High-Risk Prognostic Factors

Inclusion Criteria: 1. Histologically confirmed B-cell non-Hodgkin's lymphoma including the following types * diffuse large B-cell lymphoma * high-grade B-cell lymphoma with or without MYC and BLC2 and/or BCL6 rearrangement * transformed lymphoma * primary mediastinal large B-cell lymphoma * follicular lymphoma (FL) 2. Relapsed or refractory diseases fulfilling one of the following criteria (individuals must have received anti-CD20 monoclonal antibody and anthracycline-containing chemotherapy regimen) * Primary refractory disease, defined as disease progression after first-line immunochemotherapy or disease progression within 6 weeks of the end of the last chemotherapy * Stable disease (SD) as best response after at least 4 cycles of first-line therapy * Partial response (PR) as best response after at least 6 cycles of first-line therapy (biopsy-proven residual disease is needed for individuals with Deauville score of 4) * PR as best response after at least 2 cycles of second-line therapy * Disease relapse ≤12 months after the completion of first-line immunochemotherapy * Relapsed or refractory disease after ≥2 lines of chemotherapy 3. Presence of at least one of the following high-risk prognostic factors: (1) extranodal involvement; (2) maximum diameter of the bulky mass ≥5 cm; (3) TP53 gene alterations 4. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 5. Eligible for HDCT/ASCT based on the investigator's assessment and are scheduled to undergo an ASCT sequential CAR-T treatment regimen 6. Adequate renal and hepatic function defined as: * Serum alanine aminotransferase (ALT/AST) ≤ 3 upper limit of normal (ULN) * Total bilirubin ≤1.5 mg/dL(\<3 times ULN in patients with Gilbert's syndrome, cholestasis due to hepatoportal compression adenopathy, biliary obstruction in patients with liver involvement or lymphoma) * Serum creatinine ≤1.5 ULN, or creatinine clearance (as estimated by Cockcroft Gault) ≥ 30 mL/min 7. Cardiac ejection fraction ≥ 40% 8. Baseline oxygen saturation \> 95% on room air 9. Life expectancy ≥3 months Exclusion Criteria: 1. History of autologous or allogeneic stem cell transplantation 2. Active HBV or HCV infection, defined as HBV-DNA or HCV-DNA levels above the normal upper limit, with or without abnormal liver function. Individuals with positive HBsAg or HBcAb should receive antiviral prophylaxis for at least 12 months after CAR-T cells infusion. 3. Presence of uncontrolled infection, cardio-cerebrovascular disease，coagulopathy, or connective tissue disease. 4. History of HIV infection 5. Prior chimeric antigen receptor cellular immunotherapy targeting CD19 6. Pregnant or lactating patients