GPT and steatosis: In the subsequent analysis, mechanisms underlying increased ALT levels by tocilizumab treatment were investigated by simulating two scenarios: tocilizumab-mediated inhibition of explicitly modeled IL-6 effects only (changes in CYP activity, hepatocyte regeneration, macrophage recruitment, and IL-6 cross-signaling effects) vs. tocilizumab-mediated steatosis and ROS elevation only.