Genetic Influences of Proinflammatory Cytokines on Pain Severity in Patients with Temporomandibular Disorders

This case-control study investigated single nucleotide polymorphism (SNP) genotypes (CXC motif chemokine ligand 8 (<i>CXCL8</i>): rs2227306 and rs2227307 and tumor necrosis factor (<i>TNF</i>): rs1800629) in 85 patients with pain-related temporomandibular disorders (TMDp) and 85 controls to explore their associations with TMDp presence, pain intensity (low/high), and the presence of chronic arthralgia/myalgia. TMDp was diagnosed using a validated protocol, and polymorphisms were genotyped from buccal mucosa swabs using TaqMan assays. High pain intensity individuals had an increased risk for carrying minor allele "G" (rs2227307) and "T" (rs2227306) compared to controls (76% vs. 55.3%, <i>p</i> = 0.012; 72% vs. 54.1%, <i>p</i> = 0.030, respectively). Carriers of the minor allele "G" (rs2227307) were more prevalent in TMDp patients with arthralgia compared to controls (70.30% vs. 55.30%, <i>p</i> = 0.037). According to logistic regression, the most important predictors for high pain intensity were minor allele "G" of rs2227307 (OR 2.435, 95% CI 1.123-5.282), increasing age (OR 1.038, 95% CI 1.002-1.075), and female sex (OR 4.592, 95% CI 1.289-16.361). The explored gene polymorphisms were not significant risk factors for TMDp presence. These findings highlight the importance of genetic variations, particularly rs2227307, in understanding the diverse clinical manifestations of temporomandibular disorders.