RelB within the donor graft is required for the maintenance of GVHD. Cohorts of irradiated B6D2F1 mice were given transplants of WT (n = 31) or RelB^−/− (n = 29) BM supplemented with or without purified RelB-competent T cells (TCD, n = 10). (A) Survival curves by Kaplan-Meier analysis, (B) GVHD clinical scores were determined weekly as described in “Materials and methods.” Data represent mean ± SEM from individual animals. Data were pooled from 4 similar experiments. *P < .03, WT versus RelB^−/− allo recipients.