CASP8 and Arthritis: Caspase-8 is an endogenous suppressor of RIPK signaling; therefore, we examined whether unchecked RIPK3 signaling may contribute to the aberrant responses to K/BxN serum-transfer-induced arthritis observed in our CreLysMCasp8flox/flox and CreCD11cCasp8flox/flox caspase-8-deficient mice.