Related Experiment Video
Updated: May 14, 2026
Characterization of Vascular Morphology of Neovascular Age-Related Macular Degeneration by Indocyanine Green Angiography
Published on: August 11, 2023
Increased expression of CD200 on circulating CD11b+ monocytes in patients with neovascular age-related macular
Amardeep Singh1, Mads K Falk, Thomas V F Hviid
1Department of Ophthalmology, Clinical Eye Research Unit, Copenhagen University Hospital Roskilde and University of Copenhagen, Copenhagen, Denmark. asingh@dadlnet.dk
Objective:
Dysregulation of retinal microglial activity has been implicated in the pathogenesis of neovascular age-related macular degeneration. Microglia activity can be regulated through the membrane protein CD200 and its corresponding receptor, the CD200 receptor (CD200R). Because both the ligand and the receptor are expressed on a broad spectrum of cell types, we set out to study the expression of CD200 and CD200R on CD11b+ monocytes, granulocytes, and subsets of T lymphocytes.
Design:
Prospective, case-control study.
Participants:
The study population consisted of 62 patients with neovascular age-related macular degeneration (AMD) and 44 age-matched controls without AMD.
Methods:
The participants were aged 60 years or older, had no history of immune dysfunction or cancer, and were not receiving immune-modulating therapy. All participants were subjected to a structured interview, and detailed retinal imaging was performed: fundus autofluorescence imaging, digital color fundoscopy, and spectral-domain optical coherence tomography. Fluorescein and indocyanine green angiography were performed in patients with suspected neovascular AMD. Visual acuity was measured in both eyes. Fresh venous blood was obtained and stained with monoclonal antibodies and analyzed using flow cytometry within 6 hours of phlebotomy.
Main Outcome Measures:
The percentage of CD11b+ monocytes, granulocytes, and CD4+/CD8+ T lymphocytes positive for CD200 or CD200R in patients and controls, respectively.
Results:
Patients with neovascular AMD had a higher percentage of CD11b+CD200+ monocytes and CD200+ monocytes compared with controls. Multiple regression analysis revealed that the intergroup differences observed were independent of age. Moreover, an age-related increment in CD200 expression on monocytes was observed in controls with healthy eyes, but not in patients with neovascular AMD. We did not find any differences in CD200 and CD200R expression between patients with subretinal fibrosis and patients without subretinal fibrosis.
Conclusions:
The surface expression of CD200 on circulating CD11b+ monocytes was found to be increased in patients with neovascular AMD compared with controls with healthy eyes. This novel finding supports the notion that altered regulation of the inflammatory response plays an integral role in the pathogenesis of AMD.
Financial Disclosure(S):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Insights
Neovascular age-related macular degeneration (AMD) is linked to altered CD200 expression on monocytes. This study found increased CD200 on monocytes in AMD patients, suggesting a role in disease pathogenesis.
Area of Science:
- Immunology
- Ophthalmology
- Cell Biology
Background:
- Dysregulation of retinal microglial activity is implicated in neovascular age-related macular degeneration (AMD) pathogenesis.
- Microglial activity is modulated by the CD200 protein and its receptor, CD200R.
- CD200 and CD200R are expressed on various cell types, including immune cells.
Purpose of the Study:
- To investigate the expression of CD200 and CD200R on monocytes, granulocytes, and T lymphocytes in patients with neovascular AMD.
- To compare immune cell marker expression between AMD patients and age-matched healthy controls.
Main Methods:
- A prospective, case-control study involving 62 patients with neovascular AMD and 44 controls (≥60 years old).
- Exclusion criteria included immune dysfunction, cancer, and immune-modulating therapy.
- Flow cytometry was used to analyze CD200 and CD200R expression on CD11b+ monocytes, granulocytes, and CD4+/CD8+ T lymphocytes in blood samples.
Main Results:
- Patients with neovascular AMD exhibited a higher percentage of CD11b+CD200+ monocytes and CD200+ monocytes compared to controls.
- These differences were independent of age, and age-related increases in monocyte CD200 expression were observed in controls but not in AMD patients.
- No significant differences in CD200 or CD200R expression were found between patients with and without subretinal fibrosis.
Conclusions:
- Increased surface expression of CD200 on circulating CD11b+ monocytes is a novel finding in patients with neovascular AMD.
- This suggests that altered regulation of the inflammatory response, involving CD200 on monocytes, plays a significant role in AMD pathogenesis.
- Further research into the CD200 pathway may offer new therapeutic targets for AMD.
