TY - JOUR T1 - Autoantibodies in twins discordant for rheumatoid arthritis JF - Annals of the Rheumatic Diseases JO - Ann Rheum Dis SP - 708 LP - 709 DO - 10.1136/ard.2010.132860 VL - 70 IS - 4 AU - A J Svendsen AU - J V Hjelmborg AU - A Wiik AU - G Houen AU - K O Kyvik AU - P Junker Y1 - 2011/04/01 UR - http://ard.bmj.com/content/70/4/708.abstract N2 - Rheumatoid arthritis (RA) is characterised by frequent occurrence of autoantibodies. The anti-cyclic citrullinated peptide antibodies (anti-CCP) are now used routinely as they may antedate the development of seropositive RA, because their diagnostic sensitivity and specificity is better than rheumatoid factors (RFs), and because they may predict a more severe outcome.1,–,3 Previous studies have observed an increased prevalence of RF and anti-CCP in first-degree relatives of patients with RA.4 One study on RA discordant twin pairs provided evidence for genetic effects on IgM-RF and IgG-RF independent of HLA-DR.5 Anti-CCPs have been reported to be independently associated with the HLA-DRB1 shared epitope, PTPN22 and smoking, … ER -