Leucine-rich alpha 2 glycoprotein (LRG), a new acute-phase protein, was identified based on the results of protein semi-quantitative analysis using serum samples collected from patients with rheumatoid arthritis before and after treatment with anti-TNF-α antibodies.12 Then, LRG was demonstrated to be useful for evaluating the disease activity of IBD. Here, LRG1 is linked to rheumatoid arthritis.