Are mesenchymal stem cells still effective in acute GvHD management?

Objective: Graft-versus-host disease (GvHD) is a common and serious complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT), significantly impacting transplant efficacy. In the treatment of GvHD, numerous therapeutic approaches have been explored, with mesenchymal stem cells (MSCs) emerging as a prominent immunomodulatory option. We aimed to evaluate efficacy and outcomes of using MSCs for steroid refractory acute GVHD (SR-aGvHD) management. Materials and Methods: We retrospectively analyzed data from 36 patients' who received MSCs for treatment of SR-aGvHD following allo-HSCT between 2018 and 2024 from nine transplantation centers in T & uuml;rkiye. The product consisted of umbilical cord-derived allogeneic MSCs, which were administered intravenously. Results: Our cohort was at the median age of 39 years (range: 19-61 years), with aGvHD diagnosed at a median of two months after allo-HSCT. More than half of the patients (58.3%) classified as high-grade aGvHD according to the Minnesota risk scoring. Cord blood-derived MSCs were administered at a median dose of 3.45 (range: 0.8-5) million MSCs/kg, with a median of 3th (range: 2-5) line treatment. The rate of responses exceeding partial response (PR) was approximately 20% at the first month, increasing to 24% at the second month. The six-month survival rate was 33%, with 46% of mortality attributed to sepsis and 12.5% related to GvHD. Multivariate analysis indicated that increasing age (>= 35 years) and lower platelet counts (<= 75 x10(9)/L) were associated with higher mortality (p<0.05). Conclusion: MSC therapy has shown promising potential in improving response rates in aGvHD treatment, with efficacy enhanced by younger age and higher platelet counts.