S100A12 and periodontitis: IL-22RA1, as a receptor for IL-22, is known for its role in mucosal barrier protection and epithelial repair, suggesting that increased IL-22RA1 may enhance periodontal tissue resilience.17 Although S100-A12 and TNFSF12 are often reported as upregulated in periodontitis and involved in pro-inflammatory processes,19,28 they may also have regulatory or protective roles under certain conditions.