AB1285 IGA RF IS ASSOCIATED WITH HIGH AGE OF RHEUMATOID ARTHRITIS ONSET

Background IgM RF and anti-CCP2 have been shown to associate with young age at RA diagnosis [1, 2]. By contrast, little is known about the association between other RF isotypes and age at onset, or sex. Objectives To examine the association between individual RA autoantibodies, sex and age at RA onset. Methods Anti-CCP2, IgA-, IgG- and IgM-RF were analysed centrally in baseline sera from 1600 Epidemiological Investigations in RA (EIRA) patients aged 18-70 years and classified according to the 1987 ACR criteria within one year of first symptoms. Cut-offs for RF isotypes were determined at the 98th percentile based on the EIRA RA-free controls, close to the 98.4% anti-CCP2 specificity. Results Anti-CCP2, IgA-, IgG- and IgM RF were found in 1020 (64%), 692 (43%), 529 (33%), and 916 (57%), of the patients, respectively. Mean (median) age at diagnosis among men was 54 (57) year, higher than 51 (54) years among women (p Conclusion On average, IgA RF positive (vs. negative) RA patients are almost four years older at the time of diagnosis; the opposite was found for anti-CCP2 and IgM RF. Whereas sex-differences explain the age-association for IgM RF, this is not the case for anti-CCP2 and for IgA RF. References [1] Diaz FJ, et al. Joint Bone Spine 2011;78:175. [2] Jacobsen S. Clin Rheumatol 2004;23:121. Disclosure of Interests Eleftheria Pertsinidou: None declared, Lars Klareskog Grant/research support from: Yes, but not for the presented study., Lars Alfredsson: None declared, Linda Mathsson Employee of: employed by Thermo Fisher Scientific, Monika Hansson: None declared, Helga Westerlind: None declared, Johan Askling Grant/research support from: Karolinska Institutet (JA) has or has had research agreements with the following pharmaceutical companies, mainly in the context of the ATRIS national safety monitoring programme for rheumatology biologicals: Abbvie, BMS, MSD, Eli Lilly, Pfizer, Roche, Samsung Bioepis, and UCB., Consultant for: Karolinska Institutet has received remuneration for JA participating in ad boards arranged by Lilly, Novartis, and Pfizer., Saedis Saevarsdottir Employee of: Part-time employee at deCODE Genetics/Amgen Inc, working on genetic research unrelated to this project., Johan Ronnelid: none declared