Abstract
Background: Immune reconstitution following allogeneic stem cell transplantation (SCT) can be affected by many variables in the transplant process such as the particular conditioning regimen, donor type, GVHD prophylaxis, and so on. We assessed clinical factors to contribute to the immune reconstitution status at 100 days after allogeneic SCT in patients received fludarabine based conditioning.
Methods: 114 patients received allogeneic SCT were divided into two groups according to the immune recovery status at D+100 days after SCT. Immunophenotypic analysis using flowcytometry was performed to evaluate the percentage and the absolute numbers of T cell subsets (CD3+, CD4+, and CD8+ cells), NK cells (CD16+CD56+ cells), and B cells (CD19+ cells) with serum immunoglobulin levels as well as clinical outcomes were investigated.
Results: Disease status at the time of SCT (HR 2.54, p=0.034), risk stratification by HCI-CI (HR 2.94, p=0.000), and chronic GVHD (HR 0.30, p=0.006) were significantly associated with survival outcome, while grade II~IV GVHD tended to have a negative effect on overall survival without statistical significance (HR 1.74, p=0.068). Tacrolimus based GVHD prophylactic regimen and T cell depletion with anti-thymocyte globulin or alemtuzumab (HR 6.71, p < 0.001) were significantly associated with delayed immune reconstitution of T cell subsets. T cell depletion seemed to be associated with worse overall survival. The incidence of chronic GVHD was significantly increased in normal recovery group compared to that of abnormal group (p=0.01). In addition, Ebstein-Barr virus reactivation was more frequent in abnormal group of T cell subsets (p=0.045). Events of all viral reactivation including CMV reactivation seemed to be more frequent in abnormal group of T cell subsets.
Conclusions: Immune reconstitution after SCT was affected by tacrolimus based GVHD prophylasis and T cell depletion. Delayed immune reconstitution might cause increased morbidity from viral reactivation. We need strategies to prevent infectious complications and enhance immune reconstitution according the immune recovery status following SCT.
No relevant conflicts of interest to declare.
