The effect of monoclonal antibodies on herpes virus reactivation and graft failure in children in the early period after allogeneic hematopoietic stem cell transplantation

Aim: To study herpes virus reactivation in the early post-transplant period in children treated with monoclonal antibodies and subsequent allogeneic hematopoietic stem cell transplantation (allo-HSCT) as well as analyze the effect of herpes virus infections on the development of graft failure and macrophage activation syndrome (MAS). Materials and methods. The study included a total of 249 patients who had received their first allo-HSCT between January 2018 and December 2023. We studied the incidence of virus reactivation, MAS and graft failure and analyzed graft failure risk factors. Fifty-three (21%) patients were found to have not been tested for viral infections and therefore, excluded from the study. Results. Virus reactivation before Day +100 was identified in 155 (79%) patients at a median of 24 days after allo-HSCT. A total of 81 (32.5%) patients developed graft failure, with prior herpes virus reactivation registered in 66 (75%) of them. MAS was diagnosed in 33 (13.2%) cases, with 29 of these patients later developing graft failure (mostly, primary graft failure – 18 (54%) cases). Seventy-two enrolled patients received monoclonal antibodies prior to allo-HSCT. Out of these, 46 (63.8%) children developed a viral infection, and 28.9% also experienced graft failure (chiefly, primary graft failure). Conclusion. Herpes virus reactivation, MAS and treatment with monoclonal antibodies prior to allo-HSCT are risk factors for graft failure. Pre-transplant monoclonal antibody therapy is also a risk factor for herpes virus reactivation, MAS and graft failure.