The association of anti-CD74 antibody with spondyloarthropathies

Objective: The etiopathogenesis of spondyloarthropathies (SpA) is still unclear. Recently, anti-CD74 antibody has been suspected to play a role in SpA etiopathogenesis. This study aimed to examine the levels of anti-CD74 antibody in patients with SpA and investigate their association with disease activity. Methods: This study was conducted using data from patients who were treated at the departments of rheumatology and gastroenterology between June 2013 and November 2013. The demographic and clinical characteristics of the participants and their serum IgG-type antibodies against anti-CD74 were analyzed. Results: We analyzed 111 patients with ankylosing spondylitis (AS), 108 patients with inflammatory bowel disease (IBD), and 101 healthy controls. The rate of human leukocyte antigen-B27 positivity was 86.5% in patients with AS and 21.3% in patients with IBD. The mean levels of anti-CD74 antibodies in the AS, IBD, and control groups were 6.99 +/- 3.24 ng/mL, 6.25 +/- 3.34 ng/mL, and 7.83 +/- 4.72 ng/mL, respectively. Anti-CD74 levels were higher in healthy controls than in patients with IBD (P=.009). There was no significant difference in anti-CD74 levels between the AS and IBD groups and the AS and control groups. In addition, there was no correlation between anti-CD74 levels and disease activity. Conclusion: This study could not find an association between anti-CD74 levels and SpA in Turkish patients.