Umbilical Cord Derived Mesenchymal Stromal Cells For The Treatment of Severe Steroid-resistant Graft Versus Host Disease

Inclusion Criteria: Patients are required to meet the following inclusion criteria: 1. Patients with steroid refractory grade III-IV classic acute graft versus host disease (GvHD)occurring within 100 days after transplant or induced by donor lymphocyte infusions (DLI) or T-cell add back. Steroid refractory graft versus host disease (GvHD)is defined according to Pidala and Anasetti10 as follows: a) progression of at least 1 overall grade within 3 days of optimal steroid treatment; b) failure to demonstrate any overall grade improvement over 5 to 7 days; c) incomplete response by 14 days of 2 mg/kg/day of steroid therapy. 2. Patients with persistent, recurrent, or late acute graft versus host disease (GvHD) (features of acute graft versus host disease occurring beyond 100 days, often during withdrawal of immune suppression). 3. Patients with an overlap syndrome in which diagnostic or distinctive features of chronic graft versus host disease (GvHD) and acute graft versus host disease (GvHD) appear together79. Exclusion Criteria: 1\. Inability to obtain written informed consent