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

Comparative Efficacy of Interleukin-7 and -15 Blockade in Alleviating Experimental Chronic Uveitis and Suppressing Pathogenic Memory CD4+ T Cells

Purpose

We have previously demonstrated the pathogenic function of memory CD4+ T cells, which express IL-7 receptor (IL-7R) and IL-15R, in experimental chronic autoimmune uveitis (CAU). Here, we aimed to compare the therapeutic efficacy of blocking IL-7 or IL-15 in CAU.

Methods

C57BL/6J mice were induced for CAU, then intraperitoneally injected with an anti-IL-7 antibody (Ab), an anti-IL-15 Ab, or an IgG control for 2 weeks. Disease was evaluated by weekly fundoscopy, optical coherence tomography (OCT), and full-field electroretinography for four weeks from the initiation of treatment. At week 4, retina and cervical lymph nodes (CLN) were collected for flow cytometry analysis of T-cell response.

Results

The anti-IL-7 Ab led to progressively reduced retinal infiltration and structural damage, with rapid recovery of retinal function. The anti-IL-15 Ab resulted in moderately reduced retinal infiltration and structural damage, along with a delayed, partial functional improvement. Compared to the control group, the anti-IL-7 Ab group exhibited significantly reduced disease scores from baseline on fundoscopy and OCT at week 4, and substantially improved dark-adapted (DA) a-wave and light-adapted b-wave responses at week 2; although the anti-IL-15 Ab group showed significantly improved disease from baseline only on OCT and increased DA b-waves at week 4. Both treatments effectively depleted the retinal infiltrating T cells and reduced memory Th17 cells in the CLN.

Conclusions

Our proof-of-concept study demonstrates that blocking IL-7 or IL-15 leads to specific depletion of the uveitogenic memory CD4+ T cells and disruption of disease chronicity in uveitis.

Comparative models of uveitis

Several clinical subtypes of uveitis exist yet specific immunopathogenic mechanisms involved remain unclear. Ex vivo studies are limited by lack of fresh retinal biopsies and studies have relied on aqueous humour or peripheral blood, which may not directly reflect disease. The aim of this review is to compare the various in vivo models and review their contributions to our understanding of disease processes. These models, although unable to reflect all clinical signs, have provided insight into the contribution of genes and molecules, characterisation of effector T-cells, cell trafficking into retinal tissues, the contribution of tissue-resident myeloid cells and the mechanism(s) of action of several anti-inflammatory compounds. In vivo uveitis models have provided an excellent resource with which to study the molecular and cellular processes involved. Recent refinements in models, improved imaging, and the application of omics have greatly increased the number of readouts and translational opportunities. Future approaches with in vitro models will also be discussed.

Redefining our vision: an updated guide to the ocular immune system

Balanced immune responses in the eyes are crucial to preserve vision. The ocular immune system has long been considered distinct, owing to the so-called 'immune privilege' of its component tissues. More recently, intravital imaging and transcriptomic techniques have reshaped scientific understanding of the ocular immune landscape, such as revealing the specialization of immune cell populations in the various tissues of the eye. As knowledge of the phenotypes of corneal and retinal immune cells has evolved, links to both the systemic immune system, and the central and peripheral nervous systems, have been identified. Using intravital imaging, T cells have recently been found to reside in, and actively patrol, the healthy human cornea. Disease-associated retinal microglia with links to retinal degeneration have also been identified. This Review provides an updated guide to the ocular immune system, highlighting current knowledge of the immune cells that are present in steady-state and specific diseased ocular tissues, as well as evidence for their relationship to systemic disease. In addition, we discuss emerging intravital imaging techniques that can be used to visualize immune cell morphology and dynamics in living human eyes and how these could be applied to advance understanding of the human immune system.

The association between heart failure and systemic inflammatory response index: A cross-sectional study

BACKGROUND

The systemic inflammatory response index (SIRI) is a recently developed composite index that assesses the entire extent of inflammation in the body, closely linked to heart failure (HF). This study aimed to evaluate the potential association between SIRI and HF.

METHODS

The cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) database from 2001 to 2018. SIRI is calculated based on the counts of monocytes, neutrophils, and lymphocytes. A weighted multiple-variable linear regression model examined the correlation between SIRI and HF. Using restrained cubic splines explored the nonlinear relationship between the two, and the robustness of the results was verified by subgroup analysis and interaction tests.

RESULTS

Our study included 30,294 participants, 814 of whom were diagnosed with HF and 29,480 with non-HF. The multiple linear regression analysis showed that SIRI was positively correlated with HF (OR = 1.66; 95 % CI, 1.21, 2.29) and that there was no nonlinear relationship between the two. This relationship persisted in subgroup analyses.

CONCLUSIONS

The results indicate a linear positive correlation between SIRI and HF. Further extensive prospective studies are needed to validate these findings.

Unveiling Differential Responses of Granulocytes to Distinct Immunostimulants with Implications in Autoimmune Uveitis

The perception of circulating granulocytes as cells with a predetermined immune response mainly triggered by pathogens is evolving, recognizing their functional heterogeneity and adaptability, particularly within the neutrophil subset. The involvement of these cells in the pathophysiology of autoimmune uveitis has become increasingly clear, yet their exact role remains elusive. We used an equine model for autoimmune-mediated recurrent pan-uveitis to investigate early responses of granulocytes in different inflammatory environments. For this purpose, we performed differential proteomics on granulocytes from healthy and diseased horses stimulated with IL8, LPS, or PMA. Compared to healthy horses, granulocytes from the recurrent uveitis model significantly changed the cellular abundance of 384 proteins, with a considerable number of specific changes for each stimulant. To gain more insight into the functional impact of these stimulant-specific proteome changes in ERU pathogenesis, we used Ingenuity Pathway Analysis for pathway enrichment. This resulted in specific reaction patterns for each stimulant, with IL8 predominantly promoting Class I MHC-mediated antigen processing and presentation, LPS enhancing processes in phospholipid biosynthesis, and PMA, clearly inducing neutrophil degranulation. These findings shed light on the remarkably differentiated responses of neutrophils, offering valuable insights into their functional heterogeneity in a T-cell-driven disease. Raw data are available via ProteomeXchange with identifier PXD013648.

Relationship between Uveitis and the Differential Reactivity of Retinal Microglia

Uveitis, a complicated group of ocular inflammatory diseases, can be affected by massive pathogenic contributors such as infection, autoimmunity, and genetics. Although it is well known that many pathological changes, including disorders of the immune system and disruption of the blood-retinal barrier, count much in the onset and progression of uveitis, there is a paucity of safe and effective treatments, which has exceedingly hindered the appropriate treatment of uveitis. As innate immune cells in the retina, microglia occupy a salient position in retinal homeostasis. Many studies have reported the activation of microglia in uveitis and the mitigation of uveitis by interfering with microglial reactivity, which strongly implicates microglia as a therapeutic target. However, it has been increasingly recognized that microglia are a nonhomogeneous population under different physiological and pathological conditions, which makes it essential to thoroughly have knowledge of their specific characteristics. The paper outlines the various properties of activated microglia in uveitis, summarizes the connections between their polarization patterns and the manifestations of uveitis, and ultimately is intended to enhance the understanding of microglial versatility and expedite the exploration of promising strategies for visual protection.