Treatment of rheumatoid arthritis (RA) patients with anti-tumor necrosis factor-alpha (anti-TNF-alpha) biologic agents has been associated with a reduction in the levels of specific autoantibodies, such as rheumatoid factor (RF) and anticyclic citrullinated peptide (anti-CCP), and the induction of non- organ-specific autoantibodies (antinuclear antibodies [ANAs], anti-dsDNA, and antiphospholipid antibodies [aPLs]). The mechanisms by which the blockade of anti-TNF-alpha decreases the generation of specific autoantibodies, such as anti-CCP and RF, are not yet known. However, it has been shown that these agents can downregulate the production of several inflammatory cytokines and mediators and that these anti-inflammatory effects may account for reduced autoantibody generation, particularly in the synovial compartment. Infliximab treatment leads to the induction of ANAs in 63.8% of RA patients and 49.1% of Crohn's disease (CD) patients, and anti-dsDNA antibodies in 13% of RA patients and 21.5% of CD patients, respectively. The development of ANAs and anti-dsDNA antibodies has also been described after etanercept therapy in 11% and 15% of RA patients, respectively. In the controlled trials, increases in ANA and anti-dsDNA titers were observed in 5.3% and in 12.9% of adalimumab-treated RA patients. Only limited data on the induction of aPL antibodies during TNF-alpha blocking treatment are available.