Clinical characteristics and viral load patterns in children with cytomegalovirus gastrointestinal disease after allogeneic hematopoietic stem cell transplantation.

Cytomegalovirus (CMV) reactivation in allogeneic hematopoietic stem cell transplantation (allo-HSCT) causes significant morbidity and mortality. This study aimed to investigate the clinical characteristics of children diagnosed with CMV GI disease after allo-HSCT. This was a retrospective cohort study of patients <19 years old that underwent allo-HSCT during an 11-year period. Of the 756 patients, 55.5% (n = 420) experienced post-transplant CMV DNAemia, 2.9% (n = 22) were diagnosed with proven CMV GI diseases, and the highest incidence was found in familial mismatched donors (5.6%, P = 0.029). CMV GI disease was diagnosed <100 days of transplant in 68.2% (n = 15/22), and 13.6% (n = 3/22) did not have concurrent CMV DNAemia. Patients were divided into five groups based on the patterns of CMV viremia initiation and duration post-HSCT. At 3 months post-transplant, lower CD4+ (P = 0.006) and CD8+ (P = 0.011) T-cell counts were observed in patients with waxing and waning CMV viral load titers >100 days post-transplant (groups 1-3) compared to those with CMV DNAemia only prior to 100 days post-transplant and those without concurrent CMV DNAemia (groups 4-5). A higher 1-year all-cause mortality was observed in groups 1-3 compared to groups 4-5 (42.8% vs. 0%; P = 0.051). Active surveillance and aggressive management of CMV reactivation is crucial, especially in children with delayed CD4+ and CD8+ T-cell reconstitution after allo-HSCT.