Central corneal thickness and topographic indices in Malaysian children with vernal keratoconjunctivitis.

INTRODUCTION: Vernal keratoconjunctivitis (VKC) is a chronic allergic disease characterised by intense ocular surface symptoms and corneal involvement. There is limited data about the corneal changes in children with VKC based on severity of the disease. We aimed to compare the central corneal thickness (CCT) and corneal topographic indices in Malaysian children with VKC, as well as among the varying grades of VKC severity. MATERIALS AND METHODS: This study is a comparative, crosssectional and hospital-based study. We recruited 83 children with VKC and 83 healthy children as controls. All children underwent complete ocular examinations, CCT measurement using an ultrasound pachymeter and corneal topography using a Placido disc corneal analyser. RESULTS: There was a statistically significant difference of means CCT and topographic indices in children with VKC compared to controls (p<0.05). The probability keratoconus reached 18% in children with VKC. The mean CCT was observed to be thinnest in the severe-to-very severe groups of VKC compared to the mild-to-moderate (p<0.05). The means simulated-K1 and -K2, apical keratometry, apical gradient curvature, superior-inferior index and keratoconus prediction index were significantly different in severe-tovery severe VKC compared to mild-to-moderate VKC and controls (p<0.05). However, there was no significant difference in mean cylinder value and percent probability keratoconus when comparing different groups of severity of VKC (p=0.912 and 0.070 respectively). CONCLUSION: Children with VKC have thinner CCT and topographic indices changes compared to healthy children. Similar pattern was observed between groups with VKC. Degree of astigmatism and probability of keratoconus were similar in mild-to-moderate and severe-to-very severe groups.

The new preservative-free ophthalmic formulation of bilastine 0.6% preserves the ocular surface epithelial integrity in a comparative in vitro study.

Allergic conjunctivitis (AC) is the most common form of allergic eye disease and an increasingly prevalent condition. Topical eye drop treatments are the usual approach for managing AC, although their impact on the ocular surface is not frequently investigated. The aim of this study was to perform a comparative physicochemical characterization, and in vitro biological evaluations in primary conjunctival and corneal epithelial cells of the new multidose preservative-free bilastine 0.6% and main commercially available eye drops. MTT assay was used to measure cell viability; oxidative stress was analyzed with a ROS-sensitive probe; and apoptosis was evaluated monitoring caspase 3/7 activation. Differences in pH value, osmolarity, viscosity and phosphate levels were identified. Among all formulations, bilastine exhibited pH, osmolarity and viscosity values closer to tear film (7.4, 300 mOsm/l and ~ 1.5-10 mPa·s, respectively), and was the only phosphates-free solution. Single-dose ketotifen did not induce ROS production, and single-dose azelastine and bilastine only induced a mild increase. Bilastine and single-dose ketotifen and azelastine showed high survival rates attributable to the absence of preservative in its formulation, not inducing caspase-3/7-mediated apoptosis after 24 h. Our findings support the use of the new bilastine 0.6% for treating patients with AC to preserve and maintain the integrity of the ocular surface.

Subconjunctival injection of human umbilical cord mesenchymal stem cells alleviates experimental allergic conjunctivitis via regulating T cell response.

BACKGROUND: T helper 2 (Th2) cells are thought to play critical roles in allergic conjunctivitis (AC). They release inflammatory cytokines to promote an allergic response in AC. Due to individual heterogeneity and long-term chronic management, current therapies do not always effectively control AC. Mesenchymal stem cells (MSCs) have been shown to be effective in treating allergy-related disorders, but it is unclear how exactly the Th2-mediated allergic response is attenuated. This study aims to elucidate the therapeutic effect and mechanism of the human umbilical cord MSCs (hUCMSCs) in a mouse model of experimental AC (EAC). METHODS: A mouse EAC model was established by inoculating short ragweed (SRW) pollen. After the SRW pollen challenge, the mice received a single subconjunctival or tail vein injection of 2 × 106 hUCMSCs, or subconjunctival injection of hUCMSCs conditioned medium (hUCMSC-CM), and dexamethasone eye drops was used as positive control; subsequent scratching behavior and clinical symptoms were assessed. Immunostaining and flow cytometry were carried out to show allergic reactions and the activation of CD4 + T cell subsets in the conjunctiva and cervical lymph nodes (CLNs). Gene expression was determined by RNA-seq and further verified by qRT-PCR and Western blot. Co-culture assays were performed to explore the regulatory role of hUCMSCs in the differentiation of CD4 + naive T cells (Th0) into Th2 cells. RESULTS: Subconjunctival administration of hUCMSCs resulted in fewer instances of scratching and lower inflammation scores in EAC mice compared to the tail vein delivery, hUCMSC-CM and control groups. Subconjunctival administration of hUCMSCs reduced the number of activated mast cells and infiltrated eosinophils in the conjunctiva, as well as decreased the number of Th2 cells in CLNs. After pretreatment with EAC mouse serum in vitro to mimic the in vivo milieu, hUCMSCs were able to inhibit the differentiation of Th0 into Th2 cells. Further evidence demonstrated that repression of Th2 cell differentiation by hUCMSCs is mediated by CRISPLD2 through downregulation of STAT6 phosphorylation. Additionally, hUMCSCs were able to promote the differentiation of Th0 cells into regulatory T cells in CLNs of EAC mice. CONCLUSIONS: Subconjunctival injection of hUCMSCs suppressed the Th2-allergic response and alleviated clinical symptoms. This study provides not only a potential therapeutic target for the treatment of AC but also other T cell-mediated diseases.

Interleukin-33-activated neuropeptide CGRP-producing memory Th2 cells cooperate with somatosensory neurons to induce conjunctival itch.

Allergic conjunctivitis is a chronic inflammatory disease that is characterized by severe itch in the conjunctiva, but how neuro-immune interactions shape the pathogenesis of severe itch remains unclear. We identified a subset of memory-type pathogenic Th2 cells that preferentially expressed Il1rl1-encoding ST2 and Calca-encoding calcitonin-gene-related peptide (CGRP) in the inflammatory conjunctiva using a single-cell analysis. The IL-33-ST2 axis in memory Th2 cells controlled the axonal elongation of the peripheral sensory C-fiber and the induction of severe itch. Pharmacological blockade and genetic deletion of CGRP signaling in vivo attenuated scratching behavior. The analysis of giant papillae from patients with severe allergic conjunctivitis revealed ectopic lymphoid structure formation with the accumulation of IL-33-producing epithelial cells and CGRP-producing pathogenic CD4+ T cells accompanied by peripheral nerve elongation. Thus, the IL-33-ST2-CGRP axis directs severe itch with neuro-reconstruction in the inflammatory conjunctiva and is a potential therapeutic target for severe itch in allergic conjunctivitis.

Role of Damage-Associated Molecular Patterns (DAMPs/Alarmins) in Severe Ocular Allergic Diseases.

Severe ocular allergic diseases, such as atopic keratoconjunctivitis and vernal keratoconjunctivitis, cause severe allergic inflammation in the conjunctiva and corneal epithelial damage, resulting in visual disturbances. The involvement of damage (danger)-associated molecular patterns (DAMPs/alarmins) in the pathogenesis of these diseases has been recognized. Alarmins released from damaged corneal epithelial cells or eosinophils play a critical role in the induction of corneal lesions, vicious loop of corneal injury, and exacerbation of conjunctival allergic inflammation. Alarmins in the conjunctiva also play an essential role in the development of both allergic inflammation, based on the acquired immune system, and type 2 inflammation by innate immune responses in the ocular surface. Therefore, alarmins may be a potentially important therapeutic target in severe refractory ocular allergic diseases.

Effects of rAmb a 1-Loaded PLGA-PEG Nanoparticles in a Murine Model of Allergic Conjunctivitis.

Ambrosia artemisiifolia (Amb a) contains many allergens. Allergic conjunctivitis caused by Ambrosia artemisiifolia and its related allergen-specific immunotherapy (AIT) are seldom studied at present. poly(DL-lactide-co-glycolide)-polyethylene glycol (PLGA-PEG) is a very good nano-carrier, which has been applied in the medical field. In this context, we studied the immunotherapy effect and potential mechanism of recombinant Amb a 1 (rAmb a 1)-loaded PLGA-PEG nanoparticles. A mouse allergic conjunctivitis model was established with Ambrosia artemisiifolia crude extract, and the nanoparticles were used for AIT through direct observation of conjunctival tissue, degranulation of mast cells in conjunctival tissue, serum-specific antibodies, cytokines and other assessment models. The treatment of nanoparticles enhanced the secretion of T-helper 1 (Th1) cytokine Interferon-gama (IFN-γ) and the production of immunoglobulin G (IgG)2a (IgG2a), inhibited the secretion of T-helper 2 (Th2) cytokine Interleukin (IL)-13 and IL-4 and the level of IgE. Especially, degranulation of mast cells and expression of mast cell protease-1 (MCP-1) in conjunctival tissue was reduced significantly. In this study, we proved that the nanoparticles prepared by rAmb a 1 and PLGA-PEG have an immunotherapy effect on allergic conjunctivitis in mice.

Traffic-related particulate matter aggravates ocular allergic inflammation by mediating dendritic cell maturation.

The aim of this study was to determine the effects of traffic-related particulate matter (PM) on allergic inflammation of ocular surfaces. BALB/c mice were sensitized with ovalbumin (OVA) and aluminum hydroxide via intraperitoneal injection. Two weeks later, mice were challenged with eye drops containing OVA concomitant with either traffic-related PM2.5 or vehicle eye drops. Topical OVA challenges were administered following unilateral subconjunctival injection of magnetic-bead-sorted CD11c+ dendritic cells (DC). The following were assessed: (1) clinical signs, (2) infiltration of inflammatory cells into conjunctiva, (3) serum levels of OVA-specific IgE production, and (4) T-cell cytokine secretion with topical application of PM2.5, compared to saline vehicle. PM2.5 was found to increase production of OVA-specific IgE in serum and Th2 immune response-related cytokines including interleukin (IL)-4, IL-17A, and IL-13 compared to vehicle control. It is of interest that PM2.5 treatment also elevated the population of mature DCs in draining lymph nodes (LNs). Exposure with PM2.5 was associated with a significant rise in conjunctival expression of IL-1ß, IL-6, IL-17, and TNF. After subconjunctival injection of CD11c+DCs from PM2.5-treated allergic conjunctivitis (AC) mice into naïve mice, T cell responses and OVA-specific IgE were also enhanced. Data suggest that traffic-related PM2.5 exacerbated allergic conjunctivitis as evidenced by increased infiltration of inflammatory cells into the conjunctiva and Th2 responses in the draining LNs associated with enhanced maturation of DCs. Our findings provide new insight into the hazardous potential of traffic-related PM2.5 on allergic diseases, such as asthma or atopic dermatitis.

Experimental Mouse Models of Ragweed- and Papain-Induced Allergic Conjunctivitis.

Mouse models of allergic conjunctivitis mimic various aspects of human allergic conjunctivitis. They are useful as acute models of allergic conjunctivitis to study immunological aspects of this condition. In this chapter, we will describe ragweed-pollen-induced experimental allergic conjunctivitis (mostly driven by adaptive immunity), and papain-soaked contact lens-induced experimental allergic conjunctivitis (mostly driven by innate immunity). Giemsa staining of histological sections is used for quantification of the number of infiltrating eosinophils, which is useful to evaluate the severity of the allergic inflammation. Immunohistochemical staining and quantitative PCR are used to clarify spatiotemporal expression of proinflammatory molecules in the conjunctival tissue. Flow cytometric analysis of conjunctival tissue is used for the detection of innate lymphoid cell type 2 (ILC2) in the ocular surface tissues.

Adult vernal keratoconjunctivitis.

PURPOSE OF REVIEW: Vernal keratoconjunctivitis (VKC) is a rare chronic self-limiting allergic inflammatory disease of the ocular surface mostly affecting young boys in their first decade of life. In the last few years a new clinical entity of VKC has been described: adult VKC. Two variants have been identified according to clinical onset: early (childhood VKC persisting beyond puberty) and late onset (arising de novo in adults) adult VKC. Several epidemiologic studies on VKC have been published from single tertiary centers but while the age distribution of VKC patients does show a small percentage of adults with the disease, detailed analysis on this small subset of adult VKC cases is lacking. In this review we describe pathogenesis, clinical features, diagnostic alternatives, and therapeutic alternatives of this highly invalidating disease. RECENT FINDINGS: Adult variants of VKC have same clinical manifestations of classic form, but show higher inflammatory response and increased risk of chronic fibrotic sequelae. SUMMARY: Adult VKC research could provide insights on the impact of sex hormones in the pathogenesis of allergic diseases and on the mechanisms of inflammation and fibrosis, which cause potentially vision threatening sequelae. The present review will highlight the recent developments in our understanding of this uncommon entity.

Role of ocular cytology in vernal keratoconjunctivitis.

BACKGROUND: Children with vernal keratoconjunctivitis (VKC) present symptoms that are similar to other ocular allergies, but more pronounced, and are controlled using topical steroids. To avoid excessive and prolonged use of topical steroid eye drops, over the past 20 years galenic eye drops of cyclosporine with a concentration of 1% to 2% and tacrolimus with a concentration of 0.1% have been introduced as a treatment for the severe and unresponsive forms. The main symptoms of VKC occur most frequently during the spring and tend to get worse during the summer, meaning that affected children tend to avoid exposure to sunlight. The aim of this study was to assess the most common cell types present in the conjunctiva of children with VKC, how ocular treatment can influence them, and whether affected children express a typical conjunctival pattern, which could be useful as a pathognomonic pattern of VKC, allowing us to study this rare eye disease. METHOD: This was a cohort study of 56 children, of whom 17 were not receiving any treatment at the time of testing, 14 were using steroid eye drops or had taken them in the previous 10 days, and 25 were treated with cyclosporine eye drops or tacrolimus eye drops 0.1%. RESULT: Children in group 1 (no topical therapy) express more epithelial cells, neutrophils, mast cells, eosinophils, and lymphocytes than the other two groups. CONCLUSION: Given the ease of performance, when conducting further longitudinal studies, the conjunctival cytology examination could be used, on the one hand, to diagnose VKC, especially when the clinical diagnosis is uncertain, and, on the other, to follow disease evolution and monitor the response to topical treatment.

The roles of omega-3 fatty acids and resolvins in allergic conjunctivitis.

PURPOSE OF REVIEW: Lipids are one of the most important constituents in our body. Advances of lipidomics are elucidating the new roles of various lipid molecules in allergic diseases. For example, some reports showed anti-inflammatory effects of omega-3 fatty acids (FAs), such as docosahexaenoic acid, eicosapentaenoic acid, and their metabolites, on allergic diseases. Here, we introduce the role of lipid mediators in allergic conjunctivitis mouse model. RECENT FINDINGS: Lipidomics using liquid chromatography-tandem mass spectrometry can profile numerous lipid molecules from small tissue samples such as conjunctival specimens. Lipidomics analysis showed that various inflammatory lipid mediators are produced in the conjunctival tissue of allergic conjunctivitis mouse model. Dietary omega-3 FAs reduced these inflammatory lipid mediators in the conjunctiva and alleviated allergic conjunctivitis symptoms in mouse models. In addition, the roles of specialized proresolving lipid mediators (SPMs) have been reported for allergic inflammation. SUMMARY: Lipid mediators have important roles for the pathophysiology of the allergic diseases including allergic conjunctivitis. Omega-3 FAs and SPMs are expected as new treatment tools for allergic conjunctivitis.

Pathogenesis and complications of chronic eye rubbing in ocular allergy.

PURPOSE OF REVIEW: To review the updated literature regarding eye rubbing complications and its association with ocular allergy disorders. RECENT FINDINGS: Atopy and ocular allergy disorders, mainly vernal keratoconjunctivitis (VKC), are strongly associated with rubbing-related complications, most probably via itching and watery eye sensations that trigger the habit of chronic eye rubbing. Vigorous and prolonged rubbing may lead to establishment of corneal remodeling and ectatic disorders, such as keratoconus. Keratoconus development in rubbed eyes can be caused by mechanical mechanisms of corneal thinning and its loss of rigidity, by elevated temperature of the epithelium during rubbing, by increased intraocular pressure (IOP) because of distending forces, and by inflammatory molecules that may serve as a causal mediator between eye rubbing and keratoconus. Other eye rubbing complications include acute hydrops and perforation, IOP spikes, iris prolapse and iridoschisis rupture of lens capsule and IOL dislocation, and even posterior segment disorders, such as glaucomatous optic neuropathy, retinal detachment and extrusion of implanted silicone oil in the eye. SUMMARY: Chronic eye rubbing in allergic eye diseases can lead to progression of keratoconus, and to other rare anterior and posterior segment complications. Strategies eliminating eye rubbing and its consequences are vital, mainly among at-risk populations, such as young children and individuals with allergic ocular disorders or corneal transplants.

The histaminergic control of the iridal vascular tone in rats and its influencing by topical administration of olopatadine and ranitidine.

Objective. We evaluated the histamine's role in regulating the iris vasomotricity in rats, using as a research tool topical olopatadine, a selective H1 blocker, which is indicated for the treatment of allergic conjunctivitis and ranitidine, a selective H2 blocker mainly used for the treatment of peptic ulcer disease. Methods. Two groups of six Wistar rats anesthetized with ketamine 200 mg/kg body weight were used. They received distilled water in conjunctival instillations, initially and after 5 minutes, olopatadine 2.5 mmol/ l for the first group, respectively ranitidine 2.5 mmol/ l for the second group. The changes of the iris arteriolar and venular diameters were recorded. Results. Both olopatadine and ranitidine produced statistically significant iridal arteriolar vasoconstriction and ranitidine determined statistically significant venuloconstriction, while distilled water did not produce any statistically significant effect. Conclusions. There is a vasodilator histaminergic tone exerted through the histaminergic H1 and H2 receptors in the iris arterioles and, respectively, through the H2 receptors in the iridal venules. Olopatadine, a topical H1 antagonist used in the treatment of ocular allergies, may interfere with the humoral regulation of the iris arteriolar tone. Ranitidine, an H2 antagonist, decreased the diameter of the iris arterioles and venules, when administered topically in rats.

Glucocorticoid receptor modulators CpdX and CpdX-D3 exhibit the same in vivo antiinflammatory activities as synthetic glucocorticoids.

We previously reported that the nonsteroidal compound CpdX, which was initially characterized 20 y ago as a possible gestagen and, shortly afterward, as a possible drug for treatments of inflammatory diseases, selectively triggers the NFκB/AP1-mediated tethered indirect transrepression function of the glucocorticoid receptor (GR), and could therefore be a selective glucocorticoid receptor agonistic modulator (SEGRAM). We now demonstrate that, upon administration to the mouse, CpdX and one of its deuterated derivatives, CpdX-D3, repress as efficiently as a synthetic glucocorticoid (e.g., Dexamethasone) an induced skin atopic dermatitis, an induced psoriasis-like inflammation, a house dust mite (HDM)-induced asthma-like allergic lung inflammation, a collagen-induced arthritis, an induced ulcerative colitis, and an ovalbumin-induced allergic conjunctivitis. Interestingly, in the cases of an HDM-induced asthma-like allergic lung inflammation and of a collagen-induced arthritis, the CpdX antiinflammatory activity was selectively exerted by one of the two CpdX enantiomers, namely, CpdX(eA) or CpdX-D3(eA).

Topical tacrolimus for allergic eye diseases.

PURPOSE OF REVIEW: The spectrum of allergic eye diseases includes a variety of conditions, each characterized by complex immunopathologies.Antiallergic drugs, such as antihistamines and mast cell stabilizers, are often insufficient without concomitant topical corticosteroid treatment. The chronic course of the more severe allergic eye diseases, such as vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC), limits the treatment with topical corticosteroids to short courses. In addition, topical corticosteroid treatment puts patients at high risk of developing severe ocular complications, particularly during childhood when VKC most frequently occurs.The immunopathology of chronic diseases, such as VKC and AKC, involves predominantly T lymphocytes, and as such, immunomodulators that inhibit T-cell activation seem to be the appropriate treatment for these chronic diseases. In the past years, there is an increased incidence of managing chronic allergic eye diseases with the immunomodulator tacrolimus. The current review presents an update of the recent clinical experience with topical tacrolimus for the management of chronic allergic eye diseases. RECENT FINDINGS: Topical tacrolimus significantly improves the symptoms and signs of the various forms of chronic allergic eye disease. Recent studies also demonstrate the efficacy of low concentrations of topical tacrolimus for VKC.Early medical treatment with topical tacrolimus can also prevent the development of serious ocular complications of VKC, such as shield ulcers or limbal stem cell deficiency. SUMMARY: Topical tacrolimus has significantly changed the management approaches in severe and chronic allergic eye diseases and has minimized the need for topical corticosteroids.

Current market trends in anterior ocular inflammatory disease landscape.

PURPOSE OF REVIEW: In the US anterior ocular inflammatory disease (AOID) composed of the spectrum of ocular allergies, different forms of infectious conjunctivitis, and dry eye diseases, affects over 40% of the population. This review evaluates the current economic costs for AOID associated pharmacotherapies. RECENT FINDINGS: In recent years, with improved understanding in pathophysiology of the AOID, providing novel targets for pharmacotherapy, have led to considerable improvements in outcomes for patients. Despite these advances, there continues to be a need for interventions that inhibit key inflammatory mediators or pathways in the ophthalmic space. In 2018, AOID drugs market represents ∼40% of the costs for the total ophthalmic drugs: dry eye (43%), antiinfectives (15%), antiallergics (13%), and antiinflammatory agents (29%). With increasing treatment costs, the need for improved, cost-effective modalities persists along with treatment algorithms to derive optimal benefits for patients. SUMMARY: There has been a dramatic increase in the economic burden of AOID with the annual expenditure for the prescription drugs approaching close to $11 billion in 2018. With increasing prevalence of ocular disease, further investment is required to provide more effective treatment options and deliver improved public health and economic outcomes.

Office-based ocular procedures for the allergist.

PURPOSE OF REVIEW: The aim of this study is to suggest principles for ocular procedures to be performed by allergists in their offices in helping their diagnosis of ocular diseases and suggest better interactions between allergists and ophthalmologists. RECENT FINDINGS: Diagnosis of ocular allergy is based on clinical history and signs and symptoms, with the support of in-vivo and in-vitro tests for the identification of the specific allergen. Unfortunately, ocular manifestations are frequently misdiagnosed and not properly managed. SUMMARY: A multidisciplinary allergist-ophthalmologist approach may improve early differential diagnosis and the prognosis of patients with allergic disease and conjunctivitis through shared management and earlier etiological treatment.

The proteolytic effect of mast cell tryptase to eotaxin-1/CCL11·eotaxin-2/CCL24 and eotaxin-3/CCL26 produced by conjunctival fibroblasts.

PURPOSE: To investigate the proteolytic effect of mast cell tryptase on eotaxin-1/CCL11, eotaxin-2/CCL24 and eotaxin-3/CCL26 produced by conjunctival fibroblasts. STUDY DESIGN: Experimental. METHODS: The production of eotaxin-1, -2 and -3 by conjunctival fibroblasts stimulated both with and without IL-4/IL-13 or/and TGF-ß1 was assessed by ELISA. The proteolytic activity of tryptase on eotaxins derived from conjunctival fibroblasts and recombinant eotaxins was also estimated by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). RESULTS: Conjunctival fibroblasts produced eotaxin-1 and -3, but not eotaxin-2. Stimulation with IL-4/IL-13 and TGF-ß1 synergistically increased eotaxin-1 and -3 production. Tryptase reduced the immunoreactivity of eotaxin-1 and -3 but not of eotaxin-2, due to the proteolysis of these eotaxins but not the inhibition of their m-RNA expression. CONCLUSION: Mast cell tryptase may exercise proteolytic activity on eotaxin-1 and -3 produced by conjunctival fibroblasts, resulting in partial suppression of the ability of eotaxin-1 and -3 to accumulate eosinophils in the conjunctiva. Eotaxin-2 in the tears may be a suitable biomarker of severity of allergic conjunctival disease.