Patterns of Inflammation in Experimental Autoimmune Uveitis and Their Correlation to Optical Coherence Tomography Findings in Human Uveitis

Background/Objective: Experimental autoimmune uveitis (EAU) in rats is a model of human uveitis that is pivotal for understanding the immunological mechanisms of the disease and developing therapies. In humans, optical coherence tomography (OCT) enables in vivo detection of characteristic findings in active uveitis, as well as sequelae of inflammation. This study aimed to correlate OCT findings in uveitis patients with retinal histologies from two rat models of experimental autoimmune uveitis caused by T cells with different autoantigen specificities and gene expression patterns, as well as well-known underlying immunological pathomechanisms. Methods: Patients with various noninfectious uveitis subtypes were imaged using ultrawidefield swept-source or conventional OCT. Histological cryosections from rat eyes with experimental autoimmune uveitis were stained for T cell and/or macrophage markers. Results: Typical human OCT findings were reproduced in the experimental animal model. Hyperreflective signals observed on OCT corresponded to lymphocyte infiltration in histological sections, which was typically found in perivascular regions (vasculitis), the posterior hyaloid (snowballs), and retinal infiltrations by lymphocytes and macrophages through the retinal pigment epithelium. Conclusion: Comparing in vivo OCT imaging of human uveitis with corresponding histologies from rat models improves our understanding of the type of inflammation, the extent of tissue destruction, and the immunopathogenesis.