Plasma levels of inflammatory chemokines in patients with polypoidal choroidal vasculopathy

PURPOSE: Chemokines are a group of cytokines that guide immune cell migration. We studied plasma levels of inflammatory chemokines in patients with polypoidal choroidal vasculopathy (PCV) and compared with healthy age-matched control individuals. METHODS: This was a clinic-based prospective case-control study of participants (n = 60) with either PCV (n = 26) or age-matched healthy controls (n = 34). We sampled fresh venous blood and isolated plasma for analysis. We used U-PLEX Human Assays to quantify concentrations of the inflammatory chemokines MCP-1/CCL2, RANTES/CCL5, eotaxin/CCL11, IP-10/CXCL10 and fractalkine/CX3CL1. RESULTS: Plasma levels of fractalkine was significantly higher in patients with PCV when compared to healthy controls (mean ± SD: 7291 ± 2461 pg/ml versus 5879 ± 2001 pg/ml; p = 0.021). Plasma levels of MCP-1 (p = 0.846), RANTES (p = 0.288), eotaxin (p = 0.496) and IP-10 (p = 0.352) did not differ significantly between the groups. To evaluate possible biomarker quality of fractalkine, we used a ROC analysis and found a positive but weak discriminatory ability (AUC = 0.68). CONCLUSION: Patients with PCV have a higher plasma level of fractalkine. Although the differences do not possess strong biomarker qualities, they inform on disease processes of a poorly understood disease and suggest that the fractalkine-CX3CR1 axis may be involved. As this study did not investigate local chemokine concentrations, we are unable to confirm or disprove any local chorioretinal interaction, and our findings should be interpreted with such caution.