Mesenchymal stromal cells for the prophylaxis of graft-versus-host disease after hematopoietic stem cell transplantation: A meta-analysis of randomized controlled trials.

e18549 Background: Mesenchymal stromal cells (MSCs) have emerged as a potential alternative therapeutic strategy for the prophylaxis of graft-versus-host disease (GVHD) in patients undergoing hematopoietic stem cell transplantation (HSCT). Methods: This meta-analysis included eight randomized controlled trials (RCTs) involving 570 patients. The primary outcomes assessed were overall survival (OS), the development of acute GVHD (aGVHD), and chronic GVHD (cGVHD). Secondary outcomes included primary disease relapse and adverse events. The statistical analysis was performed using Review Manager (RevMan 5.4) with a random-effects model. Results: The meta-analysis showed a significant improvement in overall survival in the MSC group compared to the control group (RR 1.12; 95% CI: 1.02-1.23), with no evidence of heterogeneity (I²=0%). MSC prophylaxis was associated with a significant reduction in the incidence of aGVHD (RR 0.67; 95% CI: 0.40-0.83, I²=33%) and cGVHD (RR 0.65; 95% CI: 0.49-0.87, I²=0%). However, no significant difference was found between the MSC and control groups regarding primary disease relapse (RR 1.00; 95% CI: 0.73-1.38, I²=0%) or the incidence of infections (RR 0.80; 95% CI: 0.57-1.11, I²=0%). In terms of patients with at least one adverse event, no statistically significant difference was observed between the two groups (RR 1.10; 95% CI: 0.74-1.63, I²=34%). Conclusions: MSC prophylaxis significantly improves overall survival and reduces the incidence of both aGVHD and cGVHD in HSCT patients, without increasing the risk of relapse, infections, or adverse events, indicating its potential as a safe and effective intervention for GVHD management.