Inhibitory effects of tocilizumab on IL-6–induced hepcidin mRNA expression in vitro. Tocilizumab (25 μg/mL) was incubated with PLC/PRF/5 (A) and Hep3B (B) hepatocyte cell lines for 30 minutes before IL-6 (10 ng/mL) stimulation. Hepcidin mRNA was assayed with quantitative real-time PCR 24 hours after IL-6 stimulation. The figures show mean ± SD of triplicate measurements. The same experiment was repeated at least 3 times with consistent results, and representative data are shown. **P < .01 by paired t test.