This is an open, single-arm, single-center, interventional clinical study. It is planned to enroll 3-6 patients with meningeal metastases from B7H3+ solid tumors and to explore, on a small scale, the efficacy of local injection of allogeneic B7H3 CAR-γδ T cells (3*107/dose) for the treatment of patients with meningeal metastases from B7H3+ solid tumors.

This study is an open, single-arm, single-center, interventional clinical study. It is planned to enroll 3-6 patients with meningeal metastases from B7H3+ solid tumors and to explore, on a small scale, the clinical response to local injection of allogeneic B7H3 CAR-γδ T cells (3*107/dose) for the treatment of patients with meningeal metastases from B7H3+ solid tumors. During the period of cell therapy, the enrolled subjects may be given additional multiple infusions of cells, after imaging, neurological function, cerebrospinal fluid cytology or the investigator's assessment of the potential benefit of continuing cell therapy. It is recommended that the frequency of multiple infusions be 2 weeks each, and the interval between infusions can be adjusted at a later stage based on the PK and clinical symptoms of the subject after infusion.

Inclusion Criteria:

1. Age ≥18 years;

2. Have a histologically or cytologically confirmed solid malignant tumor with positive B7H3 expression;

3. ECOG ≤ 2 or KPS ≥ 60;

4. Life expectancy ≥ 8 weeks as assessed by the investigator;

5. Meningeal metastases (or with brain parenchymal metastases) from any solid malignancy that is refractory to standard treatment or for which no standard treatment is available and positive cerebrospinal fluid (CSF) cytology;

6. Substantially normal bone marrow reserve function and normal hepatic and renal function (laboratory tests are required to be satisfied prior to first treatment with QH104 Cell Injection):

   White blood cell count (WBC) ≥ 3 x 109/L; Lymphocyte count (LY) ≥ 0.8 x 109/L; Hemoglobin (Hb) ≥ 90 g/L; Platelet (PLT) ≥90×109/L; Albumin transaminase (ALT) & albumin transaminase (AST) < 1.5 x ULN; Serum creatinine (Cr) < 1.5 x ULN; Total bilirubin < 1.5 x ULN; PT & PTT ≤ 1.25 × ULN.

7. Pregnancy test should be negative for women of childbearing potential and both men and women agree to use effective contraception during treatment and for 1 year thereafter;

8. Be able to understand the requirements and matters of the trial and be willing to participate in the clinical study as required;

9. Sign the trial informed consent form.

Exclusion Criteria:

1. Targeted CNS irradiation within 7 days prior to receiving the first QH104 infusion;
2. Uncontrolled comorbidities including, but not limited to: persistent or active infections, symptomatic congestive heart failure, unstable angina, cardiac arrhythmias, or psychiatric/social conditions that would limit the patient's ability to comply with study requirements;
3. Has a known psychiatric or substance abuse disorder that would interfere with cooperation with trial requirements;
4. Is receiving treatment with any other investigational drug;
5. Have a confirmed diagnosis of an immunodeficiency disorder;
6. Have an active infection requiring systemic treatment;
7. Inability to perform an MRI;
8. Serious cardiovascular compromise: history of New York Heart Association (NYHA) class II or greater congestive heart failure, unstable angina, myocardial infarction or stroke within 6 months of first dose, or arrhythmia requiring treatment at screening;
9. Allergy to immunotherapy and related cells;
10. Prior treatment with CAR-T and other immune cell therapy;
11. Other reasons, in the opinion of the investigator, why participation in this study is not appropriate.