The most important autoimmune diseases are rheumatoid arthritis (RA), and systemic lupus erythematous (SLE). Rheumatoid arthritis (RA) is a chronic, progressive, inflammatory autoimmune disease that is associated with articular, extra-articular and systemic effects. Systemic lupus erythematous (SLE) is a disorder of immune regulation resulting in chronic inflammation that affects many organs with the production of autoantibodies.