MCP-1 promoter polymorphism in Spanish patients with systemic lupus erythematosus

The possible role of the functional polymorphism located in the regulatory region of the monocyte chemoattractant protein-1 (MCP-1) gene in the susceptibility to systemic lupus erythematosus (SLE) was investigated. Two hundred and seventy-six SLE patients (among them, 99 with lupus nephritis and 55 with cutaneous vasculitis) and 194 ethnically matched healthy controls were included in the study. Genotyping for -2518 (A/G) MCP-1 gene polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. No association between -2518 (A/G) MCP-1 polymorphism and susceptibility to SLE nor to lupus nephritis was found. However, a significant increase in the frequency of genotype AG and a decrease in the frequency of genotype AA were found among patients with cutaneous vasculitis (51% of AG vs. 32% in individuals without cutaneous vasculitis; P=0.008, OR=2.2, 95% CI: 1.18-4.25; and 47% of AA vs. 64%; P=0.03, OR=0.5, 95% CI: 0.27-0.96, respectively). These results indicate an association between the presence of G at position -2518 in the MCP-1 promoter region and the presence of cutaneous vasculitis among patients with SLE. This polymorphism does not seem to influence the susceptibility to SLE nor the appearance of lupus nephritis. Further studies are necessary in order to elucidate the role of this polymorphism in the pathogenesis of other inflammatory autoimmune diseases.