Mor-Vaknin N, Kappes F, Dick AE et al. Arthritis Rheum 2011;63:556–67.
DEK is a nuclear phosphoprotein that has been identified as an antigen in juvenile idiopathic arthritis (JIA). This group found that DEK protein and anti-DEK antibodies form immune complexes in some JIA synovial fluids, and that a particular post-translational modification (acetylation) might be involved in its recognition as an autoantigen.
In 1994, antibodies directed against DEK were recognized in a subset of patients with juvenile idiopathic arthritis (JIA), especially oligoarticular JIA, and also possibly with JIA-associated uveitis [1]. DEK is a protein typically found in the nucleus, where it participates in mRNA splicing and other cellular processes. It can also be released by macrophages, including in small membrane-bound vesicles called exosomes, where it can function as a chemoattractant for neutrophils. Antibodies against DEK are not specific to JIA and have also been identified in some patients with lupus, sarcoidosis, and rheumatoid arthritis (RA), but DEK appears rare in healthy individuals. In no other disease does it approach the frequency reported in oligoarticular JIA (in around 80% of cases).