Haploidentical allogeneic hematopoietic stem cell transplantation increases the risk of cytomegalovirus infection in adult patients with acute leukemia

Background: Owing to the shortage of hematopoietic stem cells from matched sibling donors (MSD) and matched unrelated donors (MUD), the number of patients undergoing haploidentical allogeneic hematopoietic stem cell transplantation (allo-HSCT) has rapidly increased. Despite a comparable overall survival (OS) and leukemia-free survival using this approach, some evidence suggests that haploidentical allo-HSCT recipients have a higher incidence of cytomegalovirus (CMV) infection, though this has not been clearly established. Methods: This study retrospectively compared the cumulative incidence of CMV DNAemia, 2-year OS, and leukemia-free survival rates in acute leukemia patients with MSD (n = 41), MUD (n = 18), and haploidentical donor allografts (n = 21). Results: The cumulative incidences of CMV DNAemia at day 180 in the MSD, MUD, and haploidentical groups were 39.0, 55.6, and 85.7%, respectively (P < 0.000). As less than 50% of patients in the MSD group were detected to have CMV DNAemia, the median time to CMV DNAemia detection in patients allografted with MSD could not be obtained. However, it was 42 and 29 days, respectively, for the MUD and haploidentical groups. Multivariate analysis revealed that haploidentical allo-HSCT (MSD vs. haploidentical: HR: 0.26; 95% CI: 0.09-0.78; P = 0.017) and age (HR: 1.03; 95% CI: 1.01-1.06; P = 0.011) increased CMV infection. Finally, MSD, MUD, and haploidentical allo-HSCT provided comparable 2-year OS rates (52.1%, 65.5%, and 65.6%; P = 0.425) and 2-year leukemia-free survival rates (67.1%, 68.3%, and 80.7%, P = 0.837). Conclusion: The CMV incidence was higher for haploidentical allo-HSCT than for MSD and MUD allo-HSCT; this could be explained by graft-versus-host disease prophylaxis by multiple immunosuppressants.