Loss of caspase-8 in T cells suppresses the hypergammaglobulinemia caused by loss of Bim. (A) Levels of IgM, IgG1, IgG2a, IgG2b, and IgG3 in sera of 6 mo or older WT, Bim^−/−, tcasp8^−/−, and tcasp8^−/−Bim^−/− mice (n = 18–30). (B) Levels of ANA in sera of 6 mo or older tcasp8^−/−Bim^−/−, tcasp8^−/−, Bim^−/−, and WT mice. Solid horizontal lines represent the mean for each genotype. *, P < 0.05 compared with WT mice; •, P < 0.05 compared with tcasp8^−/− mice; Δ, P < 0.05 compared with Bim^−/− mice.