Abstract: BACKGROUND: Despite unrelated cord blood transplantation is expected to become an important method for treating malignant hematological diseases, the manifestation and clinical characteristics of acute graft-versus-host disease in the gastrointestinal tract still require further in-depth investigation. 
OBJECTIVE: To analyze the clinical characteristics of intestinal acute graft-versus-host disease after unrelated cord blood transplantation. 
METHODS: A retrospective analysis was conducted on 668 malignant hematological disease patients after unrelated cord blood transplantation who underwent hematopoietic stem cell transplantation subspecialty in the Department of Hematology, First Affiliated Hospital of University of Science and Technology of China from December 2016 to December 2020. Among them, clinical data of 138 patients with intestinal acute graft-versus-host disease were analyzed, including 76 males and 62 females, with a median age of 13 (1-62) years. All patients were treated with a myeloablative regimen (without antihuman thymocyte globulin) and cyclosporin A combined with mycophenolate mofetil to prevent graft-versus-host disease.
RESULTS AND CONCLUSION: (1) The patients with intestinal acute graft-versus-host disease had diarrhea of varying degrees, most of which were yellow-green, yellow-brown watery stools or mucous stools. 53 patients (38.4%) had blood stools, 82 patients (57.9%) had skin involvement, 18 patients (13.0%) had a secondary intestinal bacterial infection, and 90 patients (65.2%) had cytomegaloviremia. (2) The clinical characteristics of patients (70 cases, 50.7%) with grade 1-2 intestinal acute graft-versus-host disease were compared with those (68 cases, 49.3%) with grade 3-4 intestinal acute graft-versus-host disease. It was found that the age of grade 3-4 intestinal acute graft-versus-host disease patients was higher than that of grade 1-2 intestinal acute graft-versus-host disease patients (P < 0.001), and they were complicated with cytomegaloviremia probably (P=0.035). Diarrhea lasted longer (P=0.00) and the length of hospital stay increased substantially (P < 0.001). However, there were no significant differences in recipient gender, pre-transplant disease status, HLA matching, diagnosis, combined skin graft-versus-host disease, and secondary intestinal infection rate in patients of the two groups. (3) These findings conclude that the clinical characteristics of intestinal acute graft-versus-host disease after unrelated cord blood transplantation are complex, which affects the prognosis and quality of life of patients seriously and requires early identification and precise treatment.

Key words: unrelated cord blood transplantation, acute graft-versus-host disease, intestinal acute graft-versus-host disease, diarrhea