Pre-Engraftment Syndrome After Autologous Stem Cell Transplantation in Relapsed or Refractory Hodgkin Lymphoma: An Association with Prior PD-1 Inhibitor Exposure

: While classical ES after ASCT was uncommon, clinically significant pre-ES occurred exclusively in PD-1-exposed patients. These early inflammatory events may represent a distinct phenotype and require prompt recognition and timely corticosteroid therapy after exclusion of infection. Prospective studies are warranted to validate these findings and refine risk stratification and monitoring strategies.