“…13,14 Periodontal pathogens possess arginine protease (PAD) and research indicates that arginine is crucial for their interactions with HLA-B27. 4 Thus, it has been provided that if an HLA-B27+ individual is infected with Porphyromonas gingivalis PADs, 7,12,[15][16][17][18][19][20] it can trigger a cytotoxic T-cell-mediated autoimmune response that is specific to HLA-B27, leading to inflammation in the joints. 4 Likewise, it has been demonstrated that the expression of HLA-B27 is linked to changes in the gut microbiota, and the difference in the abundance of certain species in gut microbiota between AS patients and healthy individuals is significant.…”