CD40 and rheumatoid arthritis: CD40 interacting with its ligand CD154 (CD40L) could trigger immune and inflammatory responses, and it has been found to be associated with several autoimmune diseases such as GD and Hashimoto’s thyroiditis (2), systemic lupus erythematosus (SLE) (36), rheumatoid arthritis (RA) (37) and multiple sclerosis (38).