Abstract : Biological therapies consisting of monoclonal antibodies and soluble receptors have revolutionized the care of rheumatologic patients. These therapies ensued from a better understanding of the physiopathology of rheumatologic disorders. Most of the latter have been concerned: rheumatoid arthritis (for about 10 years), psoriatic arthritis and ankylosing spondilitys (for more or less five years). Rheumatology was among the first disciplines to make use of these advances; it continues to benefit from the results of intense research efforts. These developments request from clinicians an increased expertise in immunology.