Graft CD3+/CD4 - CD8- T-cell ratio: a predictor of acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation in pediatric patients.

BACKGROUND: Acute graft-versus-host disease (aGVHD) remains a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study investigated the association between the graft CD3+/CD4 - CD8- T-cell ratio and the incidence of aGVHD in pediatric recipients. METHODS: A total of 112 pediatric patients with high-risk hematologic malignancies undergoing allo-HSCT were enrolled in this retrospective study. Associations between the graft CD3+/CD4 - CD8- T-cell ratio and aGVHD were evaluated using Fine-Gray regression models. Receiver operating characteristic (ROC) analysis was performed to determine the predictive performance and optimal cutoff value of the graft CD3+/CD4 - CD8- T-cell ratio. Spearman's rank correlation coefficient was used to assess correlations among different cellular subsets. RESULTS: The day-100 cumulative incidence of grade II-IV aGVHD was 41.1%. In multivariable analysis, the graft CD3+/CD4 - CD8- T-cell ratio was independently associated with grade II-IV aGVHD. ROC analysis identified 56 as the optimal cutoff value for the graft CD3+/CD4 - CD8- T-cell ratio. Patients with a high ratio had a significantly higher incidence of grade II-IV aGVHD than those with a low ratio (56.3% vs. 20.8%, P < 0.001), whereas no significant differences were observed in disease relapse or cytomegalovirus (CMV) infection. The graft CD4 - CD8- T-cell dose was positively correlated with early peripheral CD4 - CD8- T-cell recovery after transplantation. CONCLUSIONS: A higher graft CD3+/CD4 - CD8- T-cell ratio is independently associated with an increased risk of day-100 grade II-IV aGVHD in pediatric allo-HSCT recipients. Optimizing the graft CD3+/CD4 - CD8- T-cell ratio may help mitigate aGVHD, thereby serving as a practical biomarker for individualized aGVHD risk stratification.