The role of IgG N-galactosylation in spondyloarthritis

Spondyloarthritis (SpA) is a group of chronic inflammatory arthritic diseases causing inflammatory back pain and stiffness, leading to irreversible damage of joint and spine, seriously affecting the quality of life. However, the exact pathogenesis of SpA is still unknown, although the blockers of tumor necrosis factor (TNF) are a major therapeutic advance. Of interest is the association between SpA and Immunoglobulin G (IgG) N-glycosylation. IgG N-glycosylation is a process of post-translational modification (PTM) that takes part in regulating anti- and pro-inflammatory effects. A relationship between IgG N-glycosylation and the development of inflammatory arthritic diseases exists, in addition this relationship often occurs before the onset of disease. There are studies reporting the association between IgG N-glycosylation and SpA, leading to a significant amount of data being generated. Analysis of this data in a rigorous form is greatly needed, hence this review will focus on identifying the relationships that exist between IgG N-glycosylation in inflammatory arthritis. More specifically, the modification to the structure of IgG N-glycosylation via TNF blockers as a treatment, the link between disease activity and IgG N-glycosylation, and the predictive capacity of IgG N-glycosylation in SpA. Investigation of IgG N-glycosylation has demonstrated that IgG N-galactosylation plays an important role in the development and prognosis of SpA. This association provides a novel pathway to further research to improve early diagnosis and possible biomarkers for treatment of patients with SpA.