IgD promotes pannus formation by activating Wnt5A-Fzd5-CTHRC1-NF-κB signaling pathway in FLS of CIA rats and the regulation of IgD-Fc-Ig fusion protein.

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by joint inflammation, synovial hyperplasia, cartilage degeneration, bone erosion, and pannus. Immunoglobulin D (IgD) plays an important role in autoimmune diseases although the content of it in vivo is low. Increased concentrations of anti-IgD autoantibodies have been detected in many RA patients.