Clinical Study of Universal CD19 CAR-γδT Cell Injection in the Treatment of Adult Relapsed/Refractory B-cell Lymphoma

Inclusion Criteria: * Age ≥ 18 years, no gender restrictions; * Clinically diagnosed with relapsed/refractory B-cell lymphoma, malignant B- cell lymphoma (according to the Lugano (2014) criteria, with at least one evaluable tumour lesion, defined as: Lymph node lesions with a longest diameter exceeding 1.5 cm, or extranodal lesions with a longest diameter exceeding 1.0 cm), including diffuse large B-cell lymphoma (DLBCL-NOS), encompassing activated B-cell (ABC)/grossly centre B-cell (GCB) subtypes, primary mediastinal (thymic) large B-cell lymphoma (PMBCL), transformative follicular lymphoma (TFL), high-grade B-cell lymphoma (HGBCL) with MYC and BCL2 and/or BCL6 rearrangements,follicular lymphoma (FL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL) 1. Relapsed B-cell lymphoma is defined as disease progression following ≥2 systemic therapies; 2. Refractory disease is defined as failure to achieve complete remission (CR) on first-line therapy, or best response to first-line therapy being disease progression (PD), or best response after at least 4 cycles of first-line therapy being stable disease (SD)(e.g., 4 cycles of R-CHOP), or best response after at least 6 cycles being partial remission (PR) with biopsy-confirmed residual disease or disease progression within ≤6 months of treatment. * Cytologically or histologically confirmed CD19-positive tumour cell immunophenotyping; * Expected survival exceeding 3 months; * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2; * Major organ function meeting the following criteria: Echocardiogram showing left ventricular ejection fraction ≥50%; serum creatinine ≤ 1.5 × upper limit of normal (ULN); alanine aminotransferase (ALT), aspartate aminotransferase (AST) ≤ 3 × ULN; total bilirubin ≤ 1.5 × ULN; * Negative pregnancy test for women of childbearing potential; both male and female subjects must agree to use effective contraception during treatment and for 1 year thereafter; * Toxicity from prior antineoplastic therapy ≤ Grade 1 (per CTCAE version 5.0) or acceptable to the inclusion/exclusion criteria; * No significant hereditary disorders; * Ability to comprehend trial requirements and procedures, with willingness to participate in the clinical study as directed; * Signing of the trial informed consent form. Exclusion Criteria： * Presence of central nervous system (CNS) involvement or clinically significant history of CNS disorders, such as epilepsy and cerebrovascular disease; * Pregnant or lactating women, or women unwilling to use effective contraception during treatment and for 1 year post-treatment; * Unremitted other malignancies; * Patients with primary immunodeficiency or autoimmune diseases requiring immunosuppressive therapy; * Patients who received allogeneic immune cell therapy within 6 months prior to enrolment, or donor lymphocyte infusion within 6 weeks prior to enrolment; * Confirmed serum reactivity positive for anti-FMC63 and DSA; * Patients participating in other clinical trials within 4 weeks prior to enrolment; * Uncontrolled infectious diseases or other serious conditions, including but not limited to infections (Human Immunodeficiency Virus, acute or chronic active hepatitis B or C), congestive heart failure, unstable angina pectoris, arrhythmias, or conditions deemed to pose unpredictable risks by the treating physician; * History of stroke or intracranial haemorrhage within 3 months prior to enrolment; * Major surgery or trauma within 28 days prior to enrolment, or unresolved significant adverse events; * History of allergy to any component of the cell product; * Inability to comprehend or unwillingness to sign the informed consent form; * Other reasons deemed by the investigator to render the patient unsuitable for the clinical trial.