Rheumatoid arthritis (RA) is a common autoimmune disease characterized by chronic inflammation of synovial joints. In most cases this will lead to the formation of pannus tissue, ultimately leading to joint destruction. Early diagnosis, coupled with aggressive use of disease-modifying antirheumatic drugs, has been shown to have a favorable effect on the course of the disease. Therefore, early and accurate diagnosis has become increasingly important. Several sets of criteria have been published to achieve such an early diagnosis, and all of them include measurement of antibodies directed to citrullinated peptides or proteins. This review summarizes our present knowledge about the most well-known and established test to measure these antibodies, the anti-CCP test, which measures antibodies directed to cyclic citrullinated peptides. We describe the current views on how these antibodies are generated and how genetic and environmental parameters are important in this process. The anti-CCP test is more specific than the commonly used RF test (95% versus less than 90%) and has a comparable sensitivity (more than 70%). These antibodies are detectable very early in the disease and are reported to predict the development of erosive RA. Increasing evidence supports a role for these antibodies in the pathology of the disease. In conclusion, testing for anti-CCP autoantibodies is widely accepted as an indispensable tool for diagnosis and early treatment in the management of rheumatoid arthritis patients.
