Morphometric features on enhanced depth imaging optical coherence tomography scans in idiopathic posterior uveitis or panuveitis

Long-lived autoreactive memory CD4+ T cells mediate the sustained retinopathy in chronic autoimmune uveitis

Chronic uveitis comprises heterogeneous clinical entities characterized by sustained and recurrent intraocular inflammation that is believed to be driven by autoimmune responses. The management of chronic uveitis is challenging with the limited availability of efficacious treatments, and the underlying mechanisms mediating disease chronicity remain poorly understood as the majority of experimental data are derived from the acute phase of the disease (the first 2-3 weeks post-induction). Herein, we investigated the key cellular mechanisms underlying chronic intraocular inflammation using our recently established murine model of chronic autoimmune uveitis. We demonstrate unique long-lived CD44hi IL-7R+ IL-15R+ CD4+ memory T cells in both retina and secondary lymphoid organs after 3 months postinduction of autoimmune uveitis. These memory T cells functionally exhibit antigen-specific proliferation and activation in response to retinal peptide stimulation in vitro. Critically, these effector-memory T cells are capable of effectively trafficking to the retina and accumulating in the local tissues secreting both IL-17 and IFN-γ upon adoptively transferred, leading to retinal structural and functional damage. Thus, our data reveal the critical uveitogenic functions of memory CD4+ T cells in sustaining chronic intraocular inflammation, suggesting that memory T cells can be a novel and promising therapeutic target for treating chronic uveitis in future translational studies.

Significance of Hyperreflective Foci as an Optical Coherence Tomography Biomarker in Retinal Diseases: Characterization and Clinical Implications

Hyperreflective foci (HRF) is a term coined to depict hyperreflective dots or roundish lesions within retinal layers visualized through optical coherence tomography (OCT). Histopathological correlates of HRF are not univocal, spacing from migrating retinal pigment epithelium cells, lipid-laden macrophages, microglial cells, and extravasated proteinaceous or lipid material. Despite this, HRF can be considered OCT biomarkers for disease progression, treatment response, and prognosis in several retinal diseases, including diabetic macular edema, age-related macular degeneration (AMD), retinal vascular occlusions, and inherited retinal dystrophies. The structural features and topographic location of HRF guide the interpretation of their significance in different pathological conditions. The presence of HRF less than 30 μm with reflectivity comparable to the retinal nerve fiber layer in the absence of posterior shadowing in diabetic macular edema indicates an inflammatory phenotype with a better response to steroidal treatment. In AMD, HRF overlying drusen are associated with the development of macular neovascularization, while parafoveal drusen and HRF predispose to macular atrophy. Thus, HRF can be considered a key biomarker in several common retinal diseases. Their recognition and critical interpretation via multimodal imaging are vital to support clinical strategies and management.

Uveitic macular edema response to intravitreal dexamethasone implant is independent of optical coherence tomography findings

PURPOSE

To identify predictive response optical coherence tomography (OCT) findings in uveitic macular edema (UME) treated with intravitreal dexamethasone implant (DEX).

METHODS

Retrospective study of 66 eyes (53 patients) treated with DEX for UME. SD-OCT macular scans were collected prior to DEX treatment and 6 weeks and 3 months after the DEX implant. OCT images were evaluated for qualitative and quantitative characteristics (central retinal thickness, CRT and macular volume, MV). A multivariate analysis of covariance (ANCOVA) was carried out to study the predictive influence of OCT and clinical covariates on outcomes. The main outcome was a composite endpoint based on the simultaneous gain of 5 or more letters associated with a 20% or more reduction in CRT.

RESULTS

A significant improvement in BCVA at 6 weeks (mean change from baseline -0.2, SD 0.3) and 3 months (mean -0.2, SD 0.4) was observed after the DEX implant. A significant decrease in CRT (change from baseline -187.7 μm at 3 months) and MV (change from baseline -1.7 mm³ at 3 months) were also observed. An association of ≥ 5-letter improvement in BCVA and a ≥ 20% CRT reduction was observed in 44.6% of cases at 6 weeks and 31.4% at 3 months. ANCOVA multivariate analyses found CRT at 3 months independent from baseline clinical variables but from CRT.

CONCLUSION

DEX implant is an effective treatment for UME independently of basal characteristics, producing both a gain of visual acuity and improvement of macular anatomy by OCT measures at 3 months.