(A and B) OS, PFS, and relapse and nonrelapse mortality at 3 years after allogeneic HSCT for HLH. OS at 3 years after HSCT was 75% (95% CI, 51-89), while PFS at 3 years after HSCT was 71% (95% CI, 46-86). The cumulative incidence of relapse at 3 years after HSCT was 15% (95% CI, 3.4-33), while the cumulative incidence of NRM at 3 years after HSCT was 15% (95% CI, 3.5-34). Relapse indicates relapse of underlying malignancy (lymphoproliferative disorder) with or without HLH. There were no cases of isolated HLH relapse. (C and D) GVHD outcomes following allogeneic HSCT for HLH. Cumulative incidence of grade 2 to 4 aGVHD at 6 months was 29% (95% CI, 11-49) and 38% (95% CI, 18-58) at 1 year after HSCT. The cumulative incidence of grade 3 to 4 aGVHD at 6 months was 9.5% (95% CI, 1.5-27). The cumulative incidence of cGVHD at 2 years was 52% (95% CI, 29-71), while the cumulative incidence of moderate/severe cGVHD at 2 years was 29% (95% CI, 11-49).