Β-Thalassemia Treatment with KL003 Cell Injection

Inclusion Criteria: * Male or female age between 3-35 years; * Diagnosis of transfusion-dependent β-thalassemia and a history of at least 100 mL/kg/year of pRBCs or ≥8 transfusions of pRBCs per year for the prior 2 years; * Karnofsky performance status ≥70 for participants≥16 years of age; Lansky performance status of ≥70 for participants\<16 years of age; * Eligible to undergo auto-HSCT; * Willing and able to follow the research procedures and conditions, with good compliance; * Willing to receive at least the 2 years follow-up; * Participant and/or legal guardians voluntarily participated in this clinical trial and signed the informed consent form. Exclusion Criteria: * Diagnosis of composite α thalassemia; * Prior receipt of gene therapy or allo-HSCT; * Meet the criteria for allo-HSCT and with an identified willing donor with full HLA match; * Participants with severe iron overload at the time of screening; * Presence of unusual antibody of red blood cell antigens or tested positive for platelet antibody; * Known allergy to clinical trial drug (plerixafor or G-CSF or busulfan) or ingredient(DMSO etc.); * Clinically significant and active bacterial, viral, fungal, or parasitic infection as determined by the clinical investigator; * Subjects positive with the following etiological tests: human immunodeficiency virus(HIV-1-2),human cytomegalovirus (HCMV-DNA),EB virus（EBV-DNA）,HBV (HBsAg/HBV-DNA positive),HCV antibody (HCV-Ab), Human T-lymphotropic virus antibody (HTLV-Ab), Treponema pallidum antibody (TP-Ab); * Uncorrectable coagulation dysfunction or history of severe bleeding disorder; * History of major organ damage including: 1. Liver function test suggest AST or ALT levels \>3× upper limit of normal（ULN）; 2. Total serum bilirubin value\>2.5×ULN;if combined with Gilbert syndrome, total bilirubin\>3×ULN and direct bilirubin value\>2.5×ULN; 3. Left ventricular ejection fraction \<45%; 4. Baseline calculated eGFR\<60mL/min/1.73m2; 5. Pulmonary function:FEV1/FVC\<60% and/or diffusion capacity of carbon monoxide (DLco) \<60% of prediction;