Acute GVHD is a major complication and cause of death after allogeneic hematopoietic stem-cell transplantation. Even with standard prophylaxis regimens, GVHD occurs in 34 to 51% of patients within 100 days of transplantation. New research findings are summarized in a short video. To read the full article, click the link: https://nej.md/3baWUWd | The New England Journal of Medicine