The immune based pathophysiology of RA is one of the most studied. We already know that the citrullinated peptide antigen inducing antibody formation and subsequent anti-cyclic citrullinated peptide (anti-CCP) antibodies. In some patients can explain the clinical manifestations. However it is also apparent that some groups of patients with rheumatoid arthritis who do not have anti-CCP antibodies. It is possible then the presence of a variety of antigens exposed during the disease, and perhaps different clinical presentations associated with each.