Cytomegalovirus infection in pediatric haploidentical stem cell transplantation

Background: Human cytomegalovirus (CMV) is a major source of morbidity and mortality in pediatric hematopoietic stem cell transplantation (HSCT). CMV replication is mainly controlled by T-cell-mediated immunity. Despite treatment, CMV reactivation continues to have a significant adverse impact on post-transplant outcomes. In this study, we examine the clinical aspects and risk factors for CMV reactivation and disease, and the effect of therapeutic interventions in pediatric patients who underwent HSCT.

Methods: This retrospective, single-center study included pediatric patients who underwent haploidentical HSCT at King Faisal Specialist Hospital and Research Center in Riyadh, Saudi Arabia, from 2013 to 2018.

Results: A total of 94 HSCT recipients were included: 46 (48.94%) females and 48 (51.06%) males, with a median age of 5 years [interquartile range (IQR): 1.2–8.7]. As for donors, 57 (60.64%) were males and 37 (39.36%) were females, with a median age of 30.7 years (IQR: 23.0–35.3). CMV reactivation occurred in 52 (55.32%) of the HSCT patients. The overall mortality rate was 12.77% (12/94), and of those, 83.33% (10/12) were CMV positive. However, no patient developed CMV pneumonitis, gastritis, or colitis, and CMV was not identified as the direct cause of death. Regarding CMV risk factors, higher recipient age and the presence of acute graft-versus-host disease were significantly associated with CMV reactivation (P < 0.05).

Conclusion: Preventing CMV infection significantly impacts the post-transplant course, especially in the setting of mismatched donors. This study showed that preventing CMV by preemptive therapy revealed an undetectable rate of 78.85%. Current polymerase chain reaction (PCR)-directed surveillance and prophylaxis have lowered the incidence of CMV disease and persistent DNAemia.