Abstract: Objective　To explore the risk factors and clinical characteristics of cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children. Methods　The clinical data of allo-HSCT in 269 children from January 2016 to December 2018 were collected. The copies of CMV-DNA in whole blood after transplantation were monitored. The incidence, time, risk factors, and prognosis of CMV infection were analyzed. Results　A total of 269 cases (167 males and 102 females) were included and median age was months (33 - 115 months). Among them, 165 cases had CMV infection and the infection rate was 61.3%. The infection occurred 23 days (15 - 34 days) after transplantation, and the infection lasted 38 days (25 - 66 days). Multivariate logistic regression analysis showed that transplantation age > 65 months and grade Ⅱ-Ⅳ aGVHD after transplantation were risk factors for CMV infection, while sibling donor hematopoietic stem cell transplantation (Sib-HSCT) could reduce the incidence of CMV infection (P < 0.05). The occurrence of grade Ⅱ-Ⅳ aGVHD and the use of cord blood transplantation are associated with the incidence of refractory CMV infection (P < 0.05). The difference of the overall survival rate and disease-free survival rate between the refractory CMV infection group and the non-refractory CMV infection group was statistically significant (P < 0.05). Conclusion　The risk of CMV infection can be increased by older children and Ⅱ-Ⅳ aGVHD, while the risk can be reduced by Sib-HSCT. Refractory CMV infection was likely to occur after umbilical cord blood transplantation, and the initial detection time of refractory CMV infection was early and the peak value was high.

Key words: 　allogeneic hematopoietic stem cell transplantation;　cytomegalovirus infection;　risk factor;　child