Role of the CCL2/MCP-1 -2518A>G gene polymorphism in HLA-B27 associated uveitis

Acute anterior uveitis (AAU) is the most common form of uveitis. Up to 50% of patients with AAU are HLA-B27 positive. Since HLA B27 itself plays only a minor role in the overall genetic background, other genetic variants are likely to contribute to the susceptibility to AAU. The chemokine (C-C motif) ligand 2 (CCL2) gene, coding for monocyte chemoattractant protein-1 (MCP-1), a chemotactic cytokine, is involved in the induction of uveitis. A CCL2 gene polymorphism, which is characterized by an A>G substitution at nucleotide -2518 in the promoter region of CCL2 has been previously shown to affect MCP-1 synthesis. The purpose of the present study was to investigate a hypothesized association between this genetic variant and the presence of HLA-B27 associated AAU.

The study group comprised 114 patients with HLA-B27 associated AAU. One hundred and eleven healthy HLA-B27 positive individuals served as the HLA-B27 positive control group, whereas 81 healthy HLA-B27 negative individuals served as a HLA-B27 negative control group. Genotyping for the CCL2 -2518A>G polymorphism was performed by polymerase chain reaction.

Carriers of a CCL2 -2518G allele were found significantly more often in patients with HLA-B27 associated AAU than among HLA-B27 positive controls (49.2% and 31.5%, respectively; odds ratio 2.1; 95% confidence interval 1.2-3.6; p=0.007).

Our data suggest that the CCL2 -2518A>G polymorphism may play a role in HLA-B27 associated acute anterior uveitis.