C3 and rheumatoid arthritis: Ursini et al. provide an important evidence for the potential role of complement C3 as a surrogate biomarker of NAFLD in a large cohort of Rheumatoid arthritis (RA) patients at the best cut-off value of 1.23 g/l for complement C3 with a sensitivity of 76% and a specificity of 64% (18).