In addition, a novel serological biomarker, IgG/IgM or IgA anti-citrullinated-inter-alpha-trypsin inhibitor heavy chain 3 (ITIH3)542–556 peptide (ITIH3542–556 Cit, ALQECit542DYIFGNYIECit556), was identified from the sera of patients with secondary Sjögren’s syndrome in RA and then used in RA diagnoses with improved sensitivities (80–95%) and specificities (70–100%) [7]. Here, ITIH3 is linked to rheumatoid arthritis.