The effect of varicella-zoster virus reactivation on the long-term outcomes of patients undergoing allogeneic hematopoietic stem cell transplantation

Background A virus infection may lead the body to produce more immune cells of particular types or stimulate the production of new ones, both of which may have anti-leukemic effects. There has been no research on whether immune cells stimulated by varicella-zoster virus (VZV) infection have anti-leukemic effects. The objective of this investigation is to assess the impact of VZV infection on patients’ long-term survival following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods This retrospective study investigated the association between varicella-zoster virus (VZV) reactivation and outcomes in 219 individuals who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the Sun Yat-sen University’s First Affiliated Hospital. According to being diagnosed with VZV infection or not, these patients were grouped into two groups. The comparison of cumulative incidence of relapse, non-recurrent mortality, and overall survival (OS) was conducted between the two groups. Results Analyzing multivariate data, VZV reactivation was linked to lower relapse incidence in the group containing all individuals (hazard ratio [HR] = 0.27; 95% confidence interval [CI], 0.12–0.64), patients suffering from acute myeloid leukaemia (HR = 0.10; 95% CI, 0.01–0.83), and patients suffering from acute lymphoblastic leukaemia (HR = 0.25; 95% CI, 0.08–0.77). Moreover, VZV reactivation was linked with decreased non-relapse mortality in all individuals (HR = 0.20; 95% CI, 0.05–0.79), but no statistical significance was found for any disease subgroup. Further, VZV reactivation was an independent predictor for improved OS in the group containing all individuals (HR = 0.10; 95% CI, 0.03–0.29), patients suffering from acute myeloid leukaemia (HR = 0.09; 95% CI, 0.01–0.66), and patients suffering from acute lymphoblastic leukaemia (HR = 0.16; 95% CI, 0.04–0.68). Conclusion This is the first study to show that VZV reactivation following allo-HSCT is an independent predictor for lower relapse rates and improved OS, providing novel therapeutic approaches to improve patients’ long-term survival following allo-HSCT.