Fig. 3.

Overactivation of the immune system in tissue damage and excessive bone repair responses in ankylosing spondylitis. SNPs in PGE2 and IL-23/17 axis cytokines and others are clearly linked to spinal inflammation and post-inflammation repair. It is proposed that the initial microdamage to the spinal enthesis as shown in Fig. 1 leads to inflammation an immune driven tissue repair response. The same cytokine TNF and IL-23/17 pathways are responsible for both inflammation and also contributing to excessive repair responses. The dysregulation of homeostatic fine tuning of tissue repair, thus results in the characteristic post inflammation disease phenotype