Cytomegalovirus Infection and the Implications of Drug-Resistant Mutations in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Retrospective Study from a Tertiary Hospital in China.

Introduction: Drug-resistant cytomegalovirus (CMV) infection remains a challenge in the management of pediatric recipients of hematopoietic stem cell transplantation (HSCT). In this study, we retrospectively reviewed the clinical data on pediatric recipients of HSCT and identified known and unknown drug-resistant CMV variants.

Methods: A total of 221 children underwent allogeneic HSCT between October 2017 and November 2019 at Shenzhen Children's Hospital; of these, 35 patients were suspected of having drug-resistant CMV infections and were tested for drug-resistant mutations in the UL97 and UL54 genes by Sanger sequencing.

Results: Mutations in UL97 or UL54, or in both, were detected in 11 patients. Most of these mutations have not been previously reported. The UL97 mutation (A582V) was detected in only one patient who also harbored two UL54 mutations (T760X and R876W). One patient with both the G604S and T691A mutations in the UL54 gene died of CMV pneumonia. We investigated the risk factors associated with the development of drug-resistant CMV infection. Patients in whom both the donor and recipient had positive CMV serostatuses were less likely to have drug-resistant mutations (Fisher's exact test, p < 0.05).

Conclusion: Newly and previously detected CMV mutations in UL97 and UL54 may be associated with the development of drug-resistant CMV infection. The detection of these mutations may provide guidance for the management of post-transplant CMV infections.