Clinical immunology<br>Serum trypsin and TCR as novel markers for predicting disease activity in IgG4-related disease

<b>Background: </b>IgG4-related disease (IgG4-RD) is a novel disease named in recent years. Because of its varied clinical manifestations, like tumor but not tumor, it brings a great challenge to clinical diagnosis. Trypsin and T-cell receptor (TCR) are thought to mediate the regulation of B cell maturation, survival and antibody production. In this study, we investigated the clinical features and important novel markers of IgG4-RD. <br /> <b>Material and methods</b>: A prospective cohort study of 22 patients with IgG4-RD was carried out from May 2009 to December 2012, and 65 cases with acute pancreatitis, 60 cases with pancreatic cancer and 120 healthy individuals were studied as controls. Serum TCR, trypsin and IgG4 levels were measured during pre- and post-treatment in the patients with IgG4-RD and their correlations with IgG4 were also assessed.<br /> <b>Results:</b> Serum IgG4 and IgE levels in all patients were significantly increased, and tumor markers (carbohydrate antigen 19-9 and/or carbohydrate antigen 125) were also increased (12/22). Serum trypsin in patients with IgG4-RD was lower than in the ones with acute pancreatitis, pancreatic cancer, and healthy individuals. But serum TCR of IgG4-RD was significantly higher than in the pancreatic cancer group and normal controls and it was inversely correlated with the levels of IgG4 (r = –3.160, p = 0.042). <br /> <b>Conclusions</b>: The results indicate that serum TCR and trypsin might be useful markers for predicting disease activity in IgG4-RD.