Purpose: To investigate surface expression of CD11b and CD200 on circulating monocytes in patients with polypoidal choroidal vasculopathy (PCV).
Methods: This was a prospective case-control study of patients with PCV (n = 27), age-matched healthy controls (n = 27), and patients with neovascular AMD (n = 49). All participants underwent a comprehensive ocular examination. Fluorescein and indocyanine green angiography were performed in patients suspected of neovascular AMD or PCV. Polypoidal choroidal vasculopathy was angiographically categorized into those with a strong presence of a branching vascular network (BVN) (type 1) or with a faint/no clear presence of a BVN (type 2). Fresh venous blood was stained with fluorescent antibodies for flow cytometric analyses. We compared the percentages of CD11b+, CD200+, and CD11b+CD200+ monocytes between groups of diagnosis and between different angiographic subtypes of PCV.
Results: Overall, CD11b+ monocytes were both increased in patients with PCV and neovascular AMD. CD200+ and CD11b+CD200+ monocytes were increased in patients with neovascular AMD. An age-related increase in CD11b+CD200+ monocytes was absent in patients with PCV and neovascular AMD. Patients with PCV type 1 had significantly higher CD11b+, CD200+, and CD11b+CD200+ monocytes, whereas patients with PCV type 2 had levels similar to that in healthy controls.
Conclusions: We found that PCV is immunologically heterogeneous with significant differences between angiographic subtypes. Increased CD11b+ and CD200+ monocytes in those with a strong presence of BVN indicate that BVN development may be associated with retinal injury and a VEGF-mediated process that is either reflected or propelled by systemic changes in monocytes.