Autoantibodies to DEK oncoprotein in human inflammatory disease

Objective. To evaluate the specificity of anti-DEK antibodies for juvenile rheumatoid arthritis (JRA), Methods. Anti-DEK autoantibodies were measured by enzyme-linked immunosorbe nt assay (ELISA) using affinity-purified his6-DEK fusion protein. Sera from 639 subjects (417 patients with systemic autoimmune disease, 13 with sarco idosis, 44 with pulmonary tuberculosis, 125 with uveitis, and 6 with scleri tis, and 34 healthy control subjects) were screened. Reactivity was verifie d by immunoblotting and immunoprecipitation Studies using baculovirus-expre ssed human DEK. Results. Anti-DEK activity was found at the following frequencies: JRA 39.4 % (n = 71), systemic lupus erythematosus (SLE) 25.1% (n = 216), sarcoidosis 46.2% (n = 13), rheumatoid arthritis 15.5% (n = 71), systemic sclerosis 36 .0% (n = 22), polymyositis 6.2% (n = 16), and adult Still's disease 0% (n = 21), Autoantibodies also were detected in 9.1% of tuberculosis sera (n = 4 4), but were undetectable in sera from the 34 healthy controls. Western blo t and immunoprecipitation assay results correlated well with the ELISA find ings. In general, levels of anti-DEK autoantibodies were higher in SLE than in other patient subsets, including JRA. Conclusion. Anti-DEK autoantibodies are less specific for JRA than previous ly believed. They are produced in association with a variety of inflammator y conditions, many of which are associated with granuloma formation and/or predominant Th1 cytokine production. Anti-DEK antibodies may be a marker fo r a subset of autoimmunity associated with interferon-gamma production rath er than a particular disease subset.