Purpose:
Birdshot chorioretinopathy (BCR) is a bilateral, chronic uveitis primarily involving the posterior segment that often results in progressive vision loss. Histopathology on eyes with BCR has been limited, but we had the rare opportunity to study the eyes of a donor with BCR. We sought to compare immunolabeling in the eyes of this donor who was treated with immunosuppression for over 30 years to age-matched controls.
Methods:
From each eye, a macular punch and superotemporal regions were used for cryostat sectioning, and immunohistochemistry was performed on the sections using antibodies directed against CD45, intercellular adhesion molecule-1, IBA1, and GFAP. The vasculature-binding lectin, Ulex europaeus agglutinin-I (UEA-I), was also used to perform lectin histochemistry.
Results:
At death, her visual acuity was 20/25 right eye, 20/250 left eye with extensive chorioretinal atrophy, vascular attenuation, and disk pallor. Compared with controls, the BCR donor had extensive degeneration of the outer nuclear layer and retinal pigment epithelium as well as choroidal thinning with inner retinal preservation. Loss of UEA-I+ choroidal endothelial cells was extensive, and atypical intercellular adhesion molecule-1 labeling and IBA+ microglia/macrophages were present along with widespread GFAP labeling throughout the retina.
Conclusion:
The BCR may cause progressive chorioretinal and optic atrophy with long-standing increased leukocyte abundance throughout the retina and microglial activation especially at the retina-choroid interface.