This study is a single-arm, open-label, dose-escalation clinical trial to evaluate the safety, tolerability, changes and persistence of peripheral blood Treg cells, and pharmacodynamic characteristics of donor-derived Treg cell injection combined with recombinant human interleukin-2 in treating subjects with refractory cGVHD，and to preliminarily observe the efficacy of the study drugs in subjects with refractory cGVHD.
Subjects aged 18-70 years old, male or female;
The subjects had received allo-HSCT, including cord blood transplantation;
There was no improvement in cGVHD in initial treatment patients treated with > 0.5mg/kg/ day or 1 mg/kg/ day every other day for at least 4 weeks;
Steroid dependence: predtisone dose > 0.25 mg/kg/d or > 0.5 mg/kg/qod cGVHD relapse or progression; cGVHD recurred after two attempts to gradually reduce prednisone dose at an interval of at least 8 weeks, with prednisone dose > 0.25 mg/kg/day to be maintained.
Subjects had a recurrence of primary malignant disease before receiving Treg treatment;
The subjects had persistent, recurrent or delayed aGVHD;
Continuous use of prednisone >1 mg/kg/day is required;
The severity of the subject's cGVHD cannot be assessed by physical examination or laboratory examination;