Evaluating IBD-specific antiglycan antibodies in serum of patients with spondyloarthritis and rheumatoid arthritis: Are they really specific?

Objective The presence of serological markers associated with inflammatory bowel disease (IBD) has been studied in spondyloarthritis with conflicting results. The anti-glycan antibodies: anti-laminaribioside, anti-chitobioside, and anti-mannobioside carbohydrate antibodies (ALCA, ACCA, and AMCA) are serological markers previously associated with IBD. We aim to investigate the prevalence of these antibodies in spondyloarthritis in comparison with rheumatoid arthritis (RA) patients Methods Serum samples were obtained from consecutive patients with spondyloarthritis and were compared to RA and healthy controls. Anti-glycan antibodies - ALCA, ACCA and AMCA - were assessed using ELISA (Glycominds Ltd, Israel). Demographic characteristics, family history, disease pattern, skin evaluation (for PsA), disease activity and a questionnaire for gastrointestinal symptoms were recorded. Results Seventy patients were recruited: 36 ankylosing spondylitis (AS) and 28 psoriatic arthritis (PsA). No difference in ALCA or AMCA levels was observed between all the study groups. Significantly higher levels of ACCA were observed in RA patients, compared to healthy controls (p=0.002). One or more of the anti-glycan antibodies was found in 16.7%, and 3.6% of patients with AS and PsA, respectively, compared to 7.3% in healthy controls and 27% in RA (p=0.09). No correlation was found between the presence of anti-glycan antibodies and gastrointestinal symptoms. Conclusion Our data fail to show an increased prevalence of anti-glycan antibodies in AS or PsA patients. ACCA were found to be significantly higher in RA patients than in controls, and may serve as an inflammatory biomarker. The present results do not support a role for antiglycan antibodies as biomarkers for spondyloarthritis.