Allogeneic CD7 CAR γδ T Cells Therapy Recurrent/Refractory Leukemia

Allogenic CD7 CAR-γδT cell，Intravenous on day0; dose escalation (3+3) : dose 1 (1 × 10\^8 CAR+ cells) , dose 2 (3 × 10\^8CAR+ cells/kg，dose 3 (6× 10\^8 CAR+ cells）;

Intravenous fludarabine 30\~50 mg/m\^2/day on days-5, -4, and -3；

Intravenous cyclophosphamide 500\~1000 mg/m\^2/day on days -5, -4, and -3.