Abrogation of GVHD in RelB^−/− BMCs is associated with donor Th2 differentiation. BMCs were transplanted as described in Figure 1B, and sera and spleen were collected 10 days after BMT. (A) TNFα, IFNγ, and IL-5 levels were determined in the sera as described in “Materials and methods.” Results represent mean ± SEM of individual animals. Data are from 1 of 3 representative experiments. WT allo (n = 5) versus RelB^−/− allo (n = 5) or WT TCD (n = 3). *P < .05, **P = .01.