Variants in IRF5 Increase the Risk of Primary Sjögren's Syndrome in the Mexican Population

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by inflammation and damage to salivary and lacrimal glands. Its etiology involves both genetic and environmental factors. Among susceptibility genes, IRF5 has been highlighted in European populations, but evidence in non-European groups remains limited. This study evaluated whether IRF5 variants rs2004640G/T, rs2070197T/C, rs10954213G/A, and rs59110799G/T are associated with pSS susceptibility, clinical manifestations, or the presence of autoantibodies in a Mexican population. The diagnosis was confirmed by rheumatologists using the 2016 ACR-EULAR classification criteria for pSS. Genotyping was performed using TaqMan probes in 231 controls and 132 pSS patients from central Mexico. Associations were analyzed through binary logistic regression under different genetic models, adjusting for age and geographic origin. Clinical correlations were examined with SNPStats, and haplotypes were constructed using Haploview. Results showed that all four IRF5 variants were significantly associated with pSS susceptibility. Moreover, rs2004640, rs2070197, and rs10954213 variants were associated with arthritis, a frequent clinical manifestation in pSS patients. This represents the first evidence in a Latin American population demonstrating that IRF5 variants contribute to increased risk of developing pSS. These findings suggest ethnicity-specific genetic influences and highlight the importance of expanding research beyond European cohorts. Replication in larger samples and functional analyses are needed to confirm these associations and clarify their biological relevance.