Cytomegalovirus Reactivation as a Risk Factor for All-Cause Mortality in Children Undergoing Hematopoietic Stem Cell Transplantation: Experience Over Two Decades from a Tertiary Referral Center in India.

The aim of the study was to analyse the burden of cytomegalovirus (CMV) disease in children undergoing hematopoietic stem cell transplantation (HSCT) and its correlation with all-cause mortality. We performed a retrospective study in children up to 18 years of age who underwent allogeneic HSCT between February 2002 to December 2021 in the pediatric blood and marrow transplantation unit. A total of 1035 patients were included where five hundred forty-three (52.4%) patients underwent matched family donor (MFD) HSCT, 213 (20.5%) underwent matched unrelated donor (MUD) HSCT; 279 (26.9%) underwent haploidentical HSCT (T cell replete in 213 and T cell depleted in 66 patients). CMV reactivation was documented in 258 (24.9% patients). CMV was seen in 39 (7.2%) MFD, 77 (36.1%) MUD, 106 T cell replete (49.7%) and 36 T cell depleted (54.5%) transplants. CMV reactivation was predominantly documented in those where donor and recipient were positive (D + /R +) for CMV serostatus (77%)) prior to HSCT. Overall mortality rate was significantly higher in the CMV positive group (103/258, 39.9%), as compared to the CMV negative group (152/777, 19.6%) ( p value = 0.0001). CMV was the direct cause of death in 13/1035 children (1.2%). GvHD as a cause of death was found to be significantly higher among those with CMV ( n  = 32) as compared to those without CMV ( n  = 14) (35.6 versus 9%, p value = 0.0001). The incidence of CMV reactivation was noted in 25% of HSCT recipients, and predominantly in haploidentical HSCTs. CMV reactivation was shown to significantly impact all-cause mortality and there was a significantly increased risk of mortality due to GvHD among those with CMV reactivation.