Expansion Study of ALT001 in Patients With Multiple System Atrophy

Inclusion Criteria: * 1\. Age between 30 and 75 years inclusive, either sex; * 2\. Clinically established or clinically probable MSA (including both MSA-C and MSA-P subtypes); * 3\. Ability to walk independently or with the aid of a walking device for at least 10 meters; * 4\. Provision of written informed consent. Exclusion Criteria: * 1\. Evidence of other central nervous system pathologies on brain MRI at screening suggesting a diagnosis of neurodegenerative diseases other than MSA; * 2\. Other significant pathological findings on brain MRI at screening, including but not limited to: cerebral hemorrhage, acute cerebral infarction, aneurysm, vascular malformation, infectious lesions, brain tumors, or other space-occupying lesions (meningiomas or arachnoid cysts with a maximum diameter \<1 cm do not require exclusion); * 3\. Presence of immune-mediated diseases that are inadequately controlled or require treatment with biologic agents; * 4\. Known history of allergies to biologic agents, such as proteins or cell-based products; * 5\. Receipt of any vaccination within the past 1 month; * 6\. Patients with a prior definitive diagnosis of malignancy or those currently receiving anti-tumor drug therapy; * 7\. Patients with a prior definitive diagnosis of epilepsy or those currently taking anti-epileptic drugs; * 8\. Concurrent severe hepatic insufficiency, renal insufficiency, or severe cardiac insufficiency (severe hepatic insufficiency defined as ALT ≥1.5 times the upper li…