Systemic inflammatory immune signatures in a patient with CRB1 linked retinal dystrophy

TOCILIZUMAB RESOLVES REFRACTORY MACULAR EDEMA ASSOCIATED TO RETINITIS PIGMENTOSA

PURPOSE

The aim of this report is to describe the resolution of refractory cystoid macular edema (CME) associated to retinitis pigmentosa (RP) with IV tocilizumab in three patients.

METHODS

Retrospective study of a series of consecutive cases of patients treated with off-label IV tocilizumab (anti IL6) for CME refractory to acetazolamide 250 mg for 3 months. Patients were diagnosed with RP by fundus appearance, electrophysiology, visual fields, and genetic testing. A complete ophthalmic examination including spectral-domain optical coherence tomography was performed.

RESULTS

Three patients with RP and CME refractory to acetazolamide 250 mg for 3 months were treated with monthly IV tocilizumab for at least six months.All patients resolved CME and improved visual acuity after the third month of IV tocilizumab, resolving systemic and ocular adverse events related to previous treatments for CME. Tocilizumab was well tolerated with no other adverse events.

DISCUSSION

CME causes visual impairment in RP, but current treatments are usually deficient. Tocilizumab has been successfully used as treatment for refractory CME in uveitis, retinal dystrophies, and autoimmune retinopathies. This article reports, for the first time, the long-term resolution of refractory CME in RP with IV tocilizumab.

The roles of macrophage migration inhibitory factor in retinal diseases

Macrophage migration inhibitory factor (MIF), a multifunctional cytokine, is secreted by various cells and participates in inflammatory reactions, including innate and adaptive immunity. There are some evidences that MIF is involved in many vitreoretinal diseases. For example, MIF can exacerbate many types of uveitis; measurements of MIF levels can be used to monitor the effectiveness of uveitis treatment. MIF also alleviates trauma-induced and glaucoma-induced optic nerve damage. Furthermore, MIF is critical for retinal/choroidal neovascularization, especially complex neovascularization. MIF exacerbates retinal degeneration; thus, anti-MIF therapy may help to mitigate retinal degeneration. MIF protects uveal melanoma from attacks by natural killer cells. The mechanism underlying the effects of MIF in these diseases has been demonstrated: it binds to cluster of differentiation 74, inhibits the c-Jun N-terminal kinase pathway, and triggers mitogen-activated protein kinases, extracellular signal-regulated kinase-1/2, and the phosphoinositide-3-kinase/Akt pathway. MIF also upregulates Toll-like receptor 4 and activates the nuclear factor kappa-B signaling pathway. This review focuses on the structure and function of MIF and its receptors, including the effects of MIF on uveal inflammation, retinal degeneration, optic neuropathy, retinal/choroidal neovascularization, and uveal melanoma.

CRB1-Associated Retinal Dystrophy Patients Have Expanded Lewis Glycoantigen-Positive T Cells

Purpose

Eye inflammation may occur in patients with inherited retinal dystrophies (IRDs) and is seen frequently in IRDs associated with mutations in the CRB1 gene. The purpose of this study was to determine the types of inflammatory cells involved in IRDs, by deep profiling the composition of peripheral blood mononuclear cells of patients with a CRB1-associated IRD.

Methods

This study included 33 patients with an IRD with confirmed CRB1 mutations and 32 healthy controls. A 43-parameter flow cytometry analysis was performed on peripheral blood mononuclear cells isolated from venous blood. FlowSOM and manual Boolean combination gating were used to identify and quantify immune cell subsets.

Results

Comparing patients with controls revealed a significant increase in patients in the abundance of circulating CD4+ T cells and CD8+ T cells that express sialyl Lewis X antigen. Furthermore, we detected a decrease in plasmacytoid dendritic cells and an IgA+CD24+CD38+ transitional B-cell subset in patients with an IRD.

Conclusions

Patients with a CRB1-associated IRD show marked changes in blood leukocyte composition, affecting lymphocyte and dendritic cell populations. These results implicate inflammatory pathways in the disease manifestations of IRDs.

Retinitis Pigmentosa: Current Clinical Management and Emerging Therapies

Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies characterized by the degeneration of rod photoreceptors, followed by the degeneration of cone photoreceptors. As a result of photoreceptor degeneration, affected individuals experience gradual loss of visual function, with primary symptoms of progressive nyctalopia, constricted visual fields and, ultimately, central vision loss. The onset, severity and clinical course of RP shows great variability and unpredictability, with most patients already experiencing some degree of visual disability in childhood. While RP is currently untreatable for the majority of patients, significant efforts have been made in the development of genetic therapies, which offer new hope for treatment for patients affected by inherited retinal dystrophies. In this exciting era of emerging gene therapies, it remains imperative to continue supporting patients with RP using all available options to manage their condition. Patients with RP experience a wide variety of physical, mental and social-emotional difficulties during their lifetime, of which some require timely intervention. This review aims to familiarize readers with clinical management options that are currently available for patients with RP.

Diabetic Patients With Rosacea Increase the Risks of Diabetic Macular Edema, Dry Eye Disease, Glaucoma, and Cataract

PURPOSE

Inflammation plays a role in diabetic eye diseases, but the association between rosacea and eye diseases in patients with diabetes remains unknown.

DESIGN

This retrospective cohort study used claims data from the National Health Insurance Research Database in Taiwan to investigate the association between rosacea and eye diseases in patients with diabetes.

MATERIALS AND METHODS

Taiwanese patients diagnosed as having diabetes mellitus between January 1, 1997, and December 31, 2013, and using any hypoglycemic agents were included and divided into rosacea and nonrosacea groups. After applying 1:20 sex and age matching and exclusion criteria, 1:4 propensity score matching (PSM) was conducted to balance the covariate distribution between the groups. The risk of time-to-event outcome between rosacea and nonrosacea groups in the PSM cohort was compared using the Fine and Gray subdistribution hazard model.

RESULTS

A total of 4096 patients with rosacea and 16,384 patients without rosacea were included in the analysis. During a mean follow-up period of 5 years, diabetic patients with rosacea had significantly higher risks of diabetic macular edema [subdistribution hazard ratio (SHR): 1.31, 95% confidence interval (CI): 1.05-1.63], glaucoma with medical treatment (SHR: 1.11, 95% CI: 1.01-1.21), dry eye disease (SHR: 1.55, 95% CI: 1.38-1.75), and cataract surgery (SHR: 1.13, 95% CI: 1.02-1.25) compared with diabetic patients without rosacea. A cumulative incidence analysis performed up to 14 years after the index date revealed that the risks of developing ocular diseases consistently increased over time. No significant differences in diabetic retinopathy, age-related macular degeneration, retinal vascular occlusion, ischemic optic neuropathy, optic neuritis, uveitis, or retinal detachment were identified according to rosacea diagnosis. However, we observed significant associations between rosacea and psoriasis, irritable bowel syndrome, anxiety, and major depressive disorder among patients with diabetes.

CONCLUSIONS

Rosacea is associated with diabetic macular edema, glaucoma, dry eye disease, and cataract development in diabetic patients, as well as increased risks of psoriasis, irritable bowel syndrome, anxiety, and depression in diabetic patients.

CRB1-associated retinal dystrophy presenting as self-resolving opsoclonus and posterior uveitis

Purpose

To describe the unusual case of inflammatory CRB1-associated retinal dystrophy that initially presented with self-resolving opsoclonus.

Observations

We report the case of a now 2-year-old female who developed opsoclonus without myoclonus at the age of 4 months. An extensive workup for neuroblastoma and other systemic diseases was unremarkable, and all unusual eye movements self-resolved at age 10 months. Twenty-one months after initial presentation, she began having reduced visual behaviors, and comprehensive ophthalmic exam at that time revealed recurrent saccadic intrusions as well as severe, chronic retinal inflammation and dystrophic changes. An extensive infectious and inflammatory workup was negative. Genetic sequencing revealed two variants in CRB1: a heterozygous missense mutation and a heterozygous novel deletion involving exon 12. The patient was treated with monthly infliximab and methylprednisolone infusions with improvement in her optic disc and macular capillary leakage. The patient's 8-month-old sister also harbored the same variants in CRB1 and had early signs of retinal dystrophy and peripheral vascular leakage on exam.

Conclusion

Saccadic intrusions may be the first sign of a retinal dystrophy, and infants and children with this presentation should undergo a complete eye exam. We further highlight the link between CRB1-associated retinal dystrophy and inflammation, and how systemic steroids and tumor necrosis factor alpha (TNF-α) inhibitors may be effective therapies. Finally, we report a novel deletion in CRB1 that is likely highly penetrant.

Immune function in X-linked retinoschisis subjects in an AAV8-RS1 phase I/IIa gene therapy trial

This study explored systemic immune changes in 11 subjects with X-linked retinoschisis (XLRS) in a phase I/IIa adeno-associated virus 8 (AAV8)-RS1 gene therapy trial (ClinicalTrials.gov: NCT02317887). Immune cell proportions and serum analytes were compared to 12 healthy male controls. At pre-dosing baseline the mean CD4/CD8 ratio of XLRS subjects was elevated. CD11c⁺ myeloid dendritic cells (DCs) and the serum epidermal growth factor (EGF) level were decreased, while CD123⁺ plasmacytoid DCs and serum interferon (IFN)-γ and tumor necrosis factor (TNF)-α were increased, indicating that the XLRS baseline immune status differs from that of controls. XLRS samples 14 days after AAV8-RS1 administration were compared with the XLRS baseline. Frequency of CD11b⁺CD11c⁺ DCc was decreased in 8 of 11 XLRS subjects across all vector doses (1e9-3e11 vector genomes [vg]/eye). CD8⁺human leukocyte antigen-DR isotype (HLA-DR)⁺ cytotoxic T cells and CD68⁺CD80⁺ macrophages were upregulated in 10 of 11 XLRS subjects, along with increased serum granzyme B in 8 of 11 XLRS subjects and elevated IFN-γ in 9 of 11 XLRS subjects. The six XLRS subjects with ocular inflammation after vector application gave a modestly positive correlation of inflammation score to their respective baseline CD4/CD8 ratios. This exploratory study indicates that XLRS subjects may exhibit a proinflammatory, baseline immune phenotype, and that intravitreal dosing with AAV8-RS1 leads to systemic immune activation with an increase of activated lymphocytes, macrophages, and proinflammatory cytokines.

Retinal Dystrophies and the Road to Treatment: Clinical Requirements and Considerations

: Retinal dystrophies (RDs) comprise relatively rare but devastating causes of progressive vision loss. They represent a spectrum of diseases with marked genetic and clinical heterogeneity. Mutations in the same gene may lead to different diagnoses, for example, retinitis pigmentosa or cone dystrophy. Conversely, mutations in different genes may lead to the same phenotype. The age at symptom onset, and the rate and characteristics of peripheral and central vision decline, may vary widely per disease group and even within families. For most RD cases, no effective treatment is currently available. However, preclinical studies and phase I/II/III gene therapy trials are ongoing for several RD subtypes, and recently the first retinal gene therapy has been approved by the US Food and Drug Administration for RPE65-associated RDs: voretigene neparvovec-rzyl (Luxturna). With the rapid advances in gene therapy studies, insight into the phenotypic spectrum and long-term disease course is crucial information for several RD types. The vast clinical heterogeneity presents another important challenge in the evaluation of potential efficacy in future treatment trials, and in establishing treatment candidacy criteria. This perspective describes these challenges, providing detailed clinical descriptions of several forms of RD that are caused by genes of interest for ongoing and future gene or cell-based therapy trials. Several ongoing and future treatment options will be described.

Study of Usutu virus neuropathogenicity in mice and human cellular models

Usutu virus (USUV), an African mosquito-borne flavivirus closely related to West Nile virus, was first isolated in South Africa in 1959. USUV emerged in Europe two decades ago, causing notably massive mortality in Eurasian blackbirds. USUV is attracting increasing attention due to its potential for emergence and its rapid spread in Europe in recent years. Although mainly asymptomatic or responsible for mild clinical signs, USUV was recently described as being associated with neurological disorders in humans such as encephalitis and meningoencephalitis, highlighting the potential health threat posed by the virus. Despite this, USUV pathogenesis remains largely unexplored. The aim of this study was to evaluate USUV neuropathogenicity using in vivo and in vitro approaches. Our results indicate that USUV efficiently replicates in the murine central nervous system. Replication in the spinal cord and brain is associated with recruitment of inflammatory cells and the release of inflammatory molecules as well as induction of antiviral-responses without major modulation of blood-brain barrier integrity. Endothelial cells integrity is also maintained in a human model of the blood-brain barrier despite USUV replication and release of pro-inflammatory cytokines. Furthermore, USUV-inoculated mice developed major ocular defects associated with inflammation. Moreover, USUV efficiently replicates in human retinal pigment epithelium. Our results will help to better characterize the physiopathology related to USUV infection in order to anticipate the potential threat of USUV emergence.

Number of emerging arboviruses involved in human infections has increased considerably in the past years. Among them, Usutu virus (USUV) is an African mosquito-borne virus first isolated in South Africa that recently emerged. USUV infection in humans is considered to be most often asymptomatic or to cause mild clinical signs. Nonetheless, increased cases of neurological complications such as encephalitis or meningoencephalitis have been reported in Europe but the mechanisms behind this neuropathogenesis remain largely unclear. In this study we showed that USUV can infect efficiently several organs and cells of the central nervous system associated with a drastic inflammation and various deleterious effects. Our results contribute to the characterization of the neurotropism related to USUV infection.

DIFFUSE RETINAL VASCULAR LEAKAGE AND CONE-ROD DYSTROPHY IN A FAMILY WITH THE HOMOZYGOUS MISSENSE C.1429G>A (P.GLY477ARG) MUTATION IN CRB1

PURPOSE

To describe a specific cone-rod dystrophy phenotype in a family with the homozygous c.1429G>A; p.Gly477Arg mutation in CRB1. The detailed phenotype of subjects with this specific mutation has not been described previously.

METHODS

Clinical examination included full-field electroretinography and high-resolution and widefield retinal imaging and uveitis workup. Molecular genetic analysis included next-generation sequencing of known retinal dystrophy genes and Sanger sequencing for segregation analysis.

RESULTS

Three affected male siblings (26, 16, and 8 years old) were diagnosed with cone-rod dystrophy, featuring bilateral macular hypoautofluorescent lesions. In addition, the eldest brother was found to have retinal vascular leakage throughout the retina without telangiectasia. Uveitis laboratory workup was unremarkable. The homozygous c.1429G>A; p.Gly477Arg mutation in CRB1 was found to segregate with disease in this family.

CONCLUSION

To the best of our knowledge, diffuse vascular leakage without telangiectasia or exudation, with bull's eye maculopathy, has not been reported previously in CRB1-cone rod dystrophy. This expands the phenotype complexity associated with CRB1 mutations and confirms that dystrophies associated with mutations in this gene may appear with features of uveitis.

Microglial Cell Dysfunction in CRB1-Associated Retinopathies

Inherited retinal diseases encompass a large group of clinically and genetically heterogeneous diseases estimated to affect two million people worldwide. Among these people, approximately 80,000 are or will become blind in their first decades of life due to mutations in both alleles of the Crumbs homologue-1 (CRB1) gene. Microglia are the resident immune surveyor cells in the retina, and their roles have been heavily studied in several retinal diseases, including retinitis pigmentosa (RP), age-related macular degeneration, and diabetic retinopathy. However, very little is known about the role of microglia in CRB1-associated retinopathies. Thus, we here summarize the main findings described in the literature concerning inflammation and the role of microglia in CRB1-patients and CRB1-rodent models.

Zika virus induces strong inflammatory responses and impairs homeostasis and function of the human retinal pigment epithelium

BACKGROUND

Zika virus (ZIKV) has recently re-emerged as a pathogenic agent with epidemic capacities as was well illustrated in South America. Because of the extent of this health crisis, a number of more serious symptoms have become associated with ZIKV infection than what was initially described. In particular, neuronal and ocular disorders have been characterized, both in infants and in adults. Notably, the macula and the retina can be strongly affected by ZIKV, possibly by a direct effect of the virus. This is supported by the detection of replicative and infectious virus in lachrimal fluid in human patients and mouse models.

METHODS

Here, we used an innovative, state-of-the-art iPSC-derived human retinal pigment epithelium (RPE) model to study ZIKV retinal impairment.

FINDINGS

We showed that the human RPE is highly susceptible to ZIKV infection and that a ZIKV African strain was more virulent and led to a more potent epithelium disruption and stronger anti-viral response than an Asian strain, suggesting lineage differences. Moreover, ZIKV infection led to impaired membrane dynamics involved in endocytosis, organelle biogenesis and potentially secretion, key mechanisms of RPE homeostasis and function.

INTERPRETATION

Taken together, our results suggest that ZIKV has a highly efficient ocular tropism, which creates a strong inflammatory environment that could have acute or chronic adverse effects. FUND: This work was funded by Retina France, REACTing and La Région Languedoc-Roussillon.

Non-syndromic retinitis pigmentosa

Retinitis pigmentosa (RP) encompasses a group of inherited retinal dystrophies characterized by the primary degeneration of rod and cone photoreceptors. RP is a leading cause of visual disability, with a worldwide prevalence of 1:4000. Although the majority of RP cases are non-syndromic, 20-30% of patients with RP also have an associated non-ocular condition. RP typically manifests with night blindness in adolescence, followed by concentric visual field loss, reflecting the principal dysfunction of rod photoreceptors; central vision loss occurs later in life due to cone dysfunction. Photoreceptor function measured with an electroretinogram is markedly reduced or even absent. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging show a progressive loss of outer retinal layers and altered lipofuscin distribution in a characteristic pattern. Over the past three decades, a vast number of disease-causing variants in more than 80 genes have been associated with non-syndromic RP. The wide heterogeneity of RP makes it challenging to describe the clinical findings and pathogenesis. In this review, we provide a comprehensive overview of the clinical characteristics of RP specific to genetically defined patient subsets. We supply a unique atlas with color fundus photographs of most RP subtypes, and we discuss the relevant considerations with respect to differential diagnoses. In addition, we discuss the genes involved in the pathogenesis of RP, as well as the retinal processes that are affected by pathogenic mutations in these genes. Finally, we review management strategies for patients with RP, including counseling, visual rehabilitation, and current and emerging therapeutic options.

Elevated serum levels of IL-6 and CXCL9 in autoimmune retinopathy (AIR) patients

Autoimmune retinopathy (AIR) is a rare immune-mediated retinopathy associated with circulating antiretinal antibodies (ARAs). Other prominent features of AIR include visual field deficits and photoreceptor dysfunction in the setting of progressive unexplained vision loss. The role of inflammation is poorly understood in AIR. Since cytokines play a central role in the initiation and development of inflammation, we evaluated the presence of proinflammatory cytokines and chemokines in AIR patient sera. We demonstrate that IL-6 and CXCL9 are both elevated in AIR patient sera. Moreover, the presence and concentration of these 2 molecules appear to correlate with AIR patient disease severity. This cytokine profile, IL-6 and CXCL9, has been described to participate in a variety of autoimmune and inflammatory diseases. Our study provides support for an activated inflammatory process in AIR and identifies possible mechanisms that can drive autoimmunity in this disease.

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IL-6 and CXCL9 are both elevated in AIR patient sera.

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The presence and concentration of IL-6 and CXCL9 correlate with AIR patient disease severity.

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These cytokines may play a prominent role in the initiation and development of inflammation and autoimmunity.

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The data provides evidence for activated inflammatory processes in AIR.