Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapy for a variety of malignant and nonmalignant hematologic disorders, but its efficacy is limited by transplant-related complications, including acute and chronic GVHD. Letermovir for CMV prophylaxis was used in none of the high-dose group patients and in 25% of the low-dose group patients ( I p i <.001). Four patients in the high-dose group and one patient in the low-dose group experienced severe chronic GVHD. We and others have shown that low-dose TBI may improve depth and duration of remission, which resulted in a shift in practice toward more frequent inclusion of low-dose TBI in transplant conditioning as observed in the low-dose group [[9], [14]]. [Extracted from the article]