The prophylactic application of low-dose rabbit antithymocyte globulin in matched siblings HSCT with high-risk factors for graft-versus-host disease

Relapse and graft-versus-host disease (GVHD) are currently the predominant causes of mortality post allogeneic hematopoietic stem cell transplantation (allo-HSCT). The contentious use of antithymocyte globulin (ATG) for preventing GVHD in matched sibling HSCT scenarios has been a topic of significant debate. A retrospective analysis was conducted on matched sibling HSCT cases with high-risk factors for GVHD in our center from January 2018 to June 2023. Our assessment revealed that the group administered with ATG exhibited a 30 % incidence of acute GVHD (aGVHD), in contrast to 81.8 % in the non-ATG cohort (P = 0.037) among matched sibling HSCT cases with high GVHD risk factors. Furthermore, chronic GVHD (cGVHD) occurred in 20 % of the ATG group and 72.7 % of the non-ATG group (P = 0.03). Notably, the administration of ATG did not significantly impact disease relapse (p = 0.149), infection rates (p = 0.64), granulocyte recovery time (p = 0.15), platelet recovery time (p = 0.12), overall survival (p = 0.889), or disease-free survival time (p = 0.787). The use of rabbit antithymocyte globulin (r-ATG) at a 5 mg/kg dosage demonstrated a notable reduction in aGVHD and cGVHD incidences within sibling matched HSCT cases with high-risk factors for GVHD, without increasing rates of disease recurrence or infections. These findings highlight the potential benefit of using low-dose r-ATG in high-risk of GVHD sibling matched allogeneic HSCTs, although further validation with a larger cohort is necessary.