Altered proportion of CCR2+ and CX3CR1+ circulating monocytes in neovascular age‐related macular degeneration and polypoidal choroidal vasculopathy

Background We investigated the expression of chemokine receptors CCR2 (C‐C chemokine receptor) 2 and CX3CR1 (C‐X3‐C receptor 1) on circulating monocyte subsets in patients with neovascular age‐related macular degeneration (AMD) and patients with polypoidal choroidal vasculopathy (PCV). Methods We recruited patients with neovascular AMD, patients with PCV and age‐matched healthy controls for this prospective case–control study. All participants underwent comprehensive clinical examination and imaging. Freshly sampled venous blood was prepared for flow cytometry, where we determined the proportion of CCR2+‐ and CX3CR1+‐positive cells in monocyte subsets identified using monocyte identification and subgrouping surface markers CD14, CD16 and HLA‐DR. Results Patients with neovascular AMD had significantly increased proportion of CCR2+ and CX3CR1+ non‐classical monocytes. PCV type 1 was associated with significantly increased CCR2+ and CX3CR1+ in all monocyte subsets when compared to PCV type 2. Conclusions Neovascular AMD is associated with increased expression of angiogenesis‐associated chemokine receptors in the pro‐inflammatory non‐classical monocytes. PCV differs from neovascular AMD immunologically and show immunological heterogeneity across angiographic subtypes.