SAT0415 Diagnostic and predictive value of novel method for analyzing IGG galactosylation in rheumatoid arthritis. (23rd January 2014) - Ohshima, S.
Abstract : Background: While the emphasis in rheumatoid arthritis (RA) treatment is on early diagnosis and intervention, we cannot provide the certain strategies for diagnosis. It is well known that serum immunoglobulin G (IgG) from RA patient exhibit decreased galactosylation of conservative N-glycans in CH2 domains of the heavy chains. Kondo et al. developed novel high-performance liquid chromatography (HPLC) method for precise analysis of oligosaccharides of IgG 1) . Objectives: To evaluate both diagnostic and predictive value of agalactosyl IgG in RA, we analyze serum IgG oligosaccharide structures using HPLC both in established RA, and in early undifferentiated arthritis as a diagnostic marker for future development ofRA. Methods: Firstly, serum samples were collected from 94 patients with RA fulfilled the 1987-ACR-criteria, 16 with OA, 18 with SLE, and 24 with healthy subjects (HS). The percentage agalactosyl IgG oligosaccharides (%G0) were analyzed in serum samples by high performance HPLC method. Secondly, we analyzed %G0 in 144 patients with recent-onset undifferentiated arthritis (UA) defined as not fulfilling existing classification criteria. They were studied for whether UA progressed to RA after 2 year. Results: In the first study, serum levels of %G0 were significantly higher in established RA (41.5±9.1) than in HS (21.1±4.4; p<0.01), OA (26.2±7.1; p<0.05), and SLE (28.7±10.4; p<0.05). The second study comprised 144 patients (35 males; 109 females) with early UA. The following parameters were assessed at baseline: %G0, rheumatoid factor (RF), autoantibody to galactose deficient IgG (CARF) and anti-cyclic citrullinated peptide antibodies (ACPA). Of the 144 patients with early UA, 58 (40.3%) developed RA, 9 (6.2%) developed collagen disease, 33 (22.9%) diagnosed as OA, 21 (14.6%) were UA as ever, and 23 (16.0%) were healthy (transient arthropathy) within two years after registration. %G0 predicted progression of UA to RA with high accuracy (AUC=0.807) at a highest sensitivity of 79.3% among 4 diagnostic markers (Table 1 ). Moreover, combination of %G0 and ACPA predicted progression of UA to RA with highest accuracy (AUC=0.905; 95% CI, 0.835-0.962). Conclusions: In conclusion, this novel method for analyzing agalactosyl IgG revealed excellent diagnostic value inRA. %G0 as well as ACPA would contribute to prediction of RA, allowing early therapeutic decisions. Furthermore, agalactosyl IgG may be involved in pathogenesis of RA. References: Kondo A, et al. Separation of pyridylamino oligosaccharides by high-performance liquid chromatography on an amine-bearing silica column. Anal Biochem 1994, 219, (1), 21-5. Disclosure of Interest: None Declared