RIPK1 and Hepatitis: Previous in vitro and in vivo studies have reported sensitization of RIPK1-deficient cells to TNF-mediated apoptosis.27, 28 Liver expression of TNF-α, and of its receptors TNFR1/2, is rapidly induced in the ConA-induced hepatitis model (Figures 3a and c,Supplementary Figures 2A and 4A).