Generation and validation of antibody 42B1 recognizing galactose-deficient IgG for diagnosis of chronic inflammatory diseases.

Galactose-deficient (agalactosyl) IgG is significantly increased in the serum of patients with rheumatoid arthritis, and autoantibodies against it are used in clinical tests. Subsequent studies also show increased agalactosyl IgG in many chronic inflammatory diseases. In this study, we generated antibody 42B1 recognizing agalactosyl IgG and developed a new method to evaluate chronic inflammatory diseases with it. Using an ELISA with antibody 42B1, we measured serum levels of agalactosyl IgG in 32 patients with inflammatory bowel disease (IBD), 60 patients with chronic liver disease, 60 patients with chronic pancreatitis, and 32 subjects undergoing health checkups who did not have IBD. Serum agalactosyl IgG levels were increased in all patients with chronic inflammations and partially correlated with clinical parameters. Among the subjects undergoing health checkups, some subjects showed a 15 % elevation of serum agalactosyl IgG levels, suggesting possible latent chronic inflammation. Future studies will examine the 42B1 antibody ELISA in various autoimmune diseases. Altogether, the 42B1 antibody for determination of serum agalactosyl IgG levels is a novel diagnostic tool for chronic inflammation.