The tumor microenvironment's cells can promote or inhibit tumor formation, and there are no reports on the CD4/CD8 ratio's association with outcomes post allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively evaluated the pre-transplant peripheral blood CD4/CD8 ratio in 168 patients who underwent their first allo-HSCT for hematological malignancies at our institution. When patients were divided into two groups according to the median CD4/CD8 ratio 1.35 (range, 0.09-19.89), the high CD4/CD8 ratio group had a higher incidence of relapse, equivalent non-relapse mortality and worse overall survival (OS) than the low CD4/CD8 ratio group. In a multivariate analysis, the CD4/CD8 ratio was significantly associated with an increased risk of relapse, although there was a marginally significant difference in OS. The pre-transplant peripheral blood CD4/CD8 ratio could be a novel biomarker for predicting the prognosis of allo-HSCT.
Keywords: CD4/CD8 ratio; allogeneic hematopoietic stem cell transplantation; hematological malignancies; immune response; prognosis.