Prospective Clinical Study on Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosomes for the Treatment of Childhood Autism

Inclusion Criteria:

* Diagnosis meets the ICD-11 ASD criteria or DSM-5 ASD clinical diagnostic standards.
* No significant improvement in core symptoms was observed after ≥3 months of standardized behavioral intervention.
* Score ≥30 on the CARS2, indicating mild-to-moderate or more severe autism.
* Aged 3 (inclusive) to 7 (inclusive) years, regardless of gender
* Voluntary participation in this clinical study, with written informed consent provided by the patient's legal guardian, and willingness to undergo examinations, treatment, and cooperate with follow-up visits.
* In the investigator's judgment, the patient is capable of understanding and complying with study requirements.

Exclusion Criteria:

* History of severe allergic reactions.
* Any severe mental disorder or other types of autism spectrum disorders.
* History of epileptic seizures within the past six months.
* Autism secondary to epilepsy, cerebrovascular disease, or traumatic brain injury.
* Disease severity rated as normal, borderline mental disorder, or mild mental disorder on the Clinical Global Impression scale.
* Moderate or severe extrapyramidal symptoms or tardive dyskinesia.
* Severe self-injurious behavior.
* Active systemic or severe localized infections, including human immunodeficiency virus, syphilis, and hepatitis.
* Autoimmune diseases.
* Major organ impairment.
* Severe pulmonary or hematological diseases, malignancies, or immunodeficiency.
* Concurrent treatments that may interfere with the safety and efficacy evaluation of stem cell therapy.
* Participation in other clinical trials within the past three months.
* Other clinical conditions deemed by investigators as unsuitable for study inclusion.