Umbilical cord-derived mesenchymal stem cells for steroid-refractory acute graft-versus-host disease: a real-world study

Steroid-refractory acute graft-versus-host disease (SR-aGVHD), a severe complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) lacking standard second-line therapy, was studied in a retrospective analysis of 95 patients (2019-2024) at Third Hospital of Shanxi Medical University. We compared umbilical cord mesenchymal stem cells (UC-MSCs) plus standard care (n = 44) vs. standard care alone (n = 51). UC-MSCs were infused intravenously at 1-3 × 10⁶ cells/kg with three infusions per patient. The MSC group had higher complete response (CR) rates than non-MSC group: 84.1% vs. 58.8% for grade II-IV SR-aGVHD (p = 0.007) and 54.5% vs. 31.4% for grade III-IV SR-aGVHD (p = 0.034) at week 4. Liver and gut CR rates improved by 31.8% and 28.1%, respectively. Multivariate analysis identified age ≥35 years, grade IV aGVHD, and hemoglobin ≤90 g/L as independent adverse prognostic factors. After median follow-up of 27 months, overall survival (OS) did not differ (HR = 1.04, p = 0.911). UC-MSCs improve early SR-aGVHD remission; prognostic factors enable risk stratification.