Antibodies against citrullinated peptides in clinical practice and research

Since their original description ten years ago, antibodies against citrullinated peptide antigens (ACPA) have become increasingly important in the diagnosis of rheumatoid arthritis (RA). They are now considered superior to the rheumatoid factor because they can be detected earlier in the course of the disease and are more specific while showing a comparable sensitivity. However, they seem to be less suitable for monitoring specific responses to therapies and for predicting extra-articular manifestations as well as disease activity. Recent research activities center around using ACPA to further elucidate the pathogenesis of RA.