HMGB1 and xerostomia: Intraperitoneal injection of the anti-HMGB1 antibody also alleviated xerostomia by downregulating the HMGB1/TLR4/NF-kB signaling pathway and improved aquaporin protein 5 expression (81, 122). Although the detailed mechanism of SS needs to be further confirmed, therapies targeting HMGB1 are promising.