Increasing evidence sμggests a central role for the CD40L-CD40 signaling pathway in several immunogenic and inflammatory processes, including atherosclerosis. It was also found that CD40L-CD40 signaling pathways play an important role in several autoimmune diseases, including the X-linked hyper-IgM syndrome, collagen-induced arthritis, allergic encephalitis and multiple sclerosis, and acute and chronic graft vs. host diseases.