Chemokines in the limbal form of vernal keratoconjunctivitis

Ocular Surface and Tear Cytokine Changes after Cataract Surgery in Patients with Type 2 Diabetes

PURPOSE

To evaluate changes in ocular surface indices and tear cytokines after cataract surgery in type 2 diabetic patients.

METHODS

Ocular surface indices and concentrations of tear cytokines (MCP-1, IL-6, IL-8, and VEGF) were evaluated at baseline and one week and one month postoperatively.

RESULTS

Patients (30 diabetic and 30 control) were enrolled. In the diabetic group, changes in ocular symptom and tear breakup time remained until one month postoperatively (P < .05, respectively); in the control group, ocular symptom increased at one week postoperatively (P = .015). MCP-1 level in the diabetic group significantly increased postoperatively (all P < .05); however, in the control group, the IL-8 level was significantly decreased postoperatively (all P < .05). MCP-1 concentration was negatively correlated with TBUT in the diabetic group.

CONCLUSION

Diabetic patients can experience more prominent changes after surgery and these changes were accompanied by an increase of several tear cytokines.

Cellular mechanisms and effects of IL-4 receptor blockade in experimental conjunctivitis evoked by skin inflammation

Ocular surface diseases, including conjunctivitis, are recognized as common comorbidities in atopic dermatitis (AD) and occur at an increased frequency in patients with AD treated with biologics targeting IL-4 receptor α (IL-4Rα) or IL-13. However, the inflammatory mechanisms underlying this pathology are unknown. Here, we developed a potentially novel mouse model of skin inflammation-evoked conjunctivitis and showed that it is dependent on CD4+ T cells and basophils. Blockade of IL-4Rα partially attenuated conjunctivitis development, downregulated basophil activation, and led to a reduction in expression of genes related to type 2 cytokine responses. Together, these data suggest that an IL-4Rα/basophil axis plays a role in the development of murine allergic conjunctivitis. Interestingly, we found a significant augmentation of a number of genes that encode tear proteins and enzymes in anti-IL-4Rα-treated mice, and it may underlie the partial efficacy in this model and may represent candidate mediators of the increased frequency of conjunctivitis following dupilumab in patients with AD.

Therapeutic Targets in Allergic Conjunctivitis

Allergic conjunctivitis (AC) is a common condition resulting from exposure to allergens such as pollen, animal dander, or mold. It is typically mediated by allergen-induced crosslinking of immunoglobulin E attached to receptors on primed conjunctival mast cells, which results in mast cell degranulation and histamine release, as well as the release of lipid mediators, cytokines, and chemokines. The clinical result is conjunctival hyperemia, tearing, intense itching, and chemosis. Refractory and chronic cases can result in ocular surface complications that may be vision threatening. Patients who experience even mild forms of this disease report an impact on their quality of life. Current treatment options range from non-pharmacologic therapies to ocular and systemic options. However, to adequately control AC, the use of multiple agents is often required. As such, a precise understanding of the immune mechanisms responsible for this ocular surface inflammation is needed to support ongoing research for potential therapeutic targets such as chemokine receptors, cytokine receptors, non-receptor tyrosine kinases, and integrins. This review utilized several published articles regarding the current therapeutic options to treat AC, as well as the pathological and immune mechanisms relevant to AC. This review will also focus on cellular and molecular targets in AC, with particular emphasis on potential therapeutic agents that can attenuate the pathology and immune mechanisms driven by cells, receptors, and molecules that participate in the immunopathogenesis and immunopathology of AC.

Understanding Vernal Keratoconjunctivitis: Beyond Allergic Mechanisms

Vernal keratoconjunctivitis (VKC) is a chronic, recurrent, inflammatory disease of the cornea and conjunctiva mostly affecting boys in prepubertal age. VKC recurrence is characterized by intense symptoms of itching, redness, and photophobia associated with corneal damage, impairment of visual function, and quality of life. The pathogenesis of VKC has not yet been completely understood, and it is still controversial. In fact, VKC is considered an ocular allergic disease due to the involvement of immunoglobulin E, eosinophils, and mast cells, and of a lymphocyte T-helper type 2 reaction. However, approximately half of VKC patients have negative allergological history and testing, suggesting that other pathogenic mechanisms participate in VKC development and severity. Specifically, evidence suggests that genetic, endocrine, neuronal factors and an imbalance of innate immunity are involved in the pathogenesis of VKC. The purpose of this review is to summarize evidence on the pathogenic role of innate immunity, neuroimmune reaction, and hormonal changes in VKC. Increasing understanding of the pathogenic mechanisms behind VKC may lead to the identification of novel biomarkers for diagnosis and/or potential therapeutic targets in order to improve the management of this challenging condition.

Chemokines in allergic conjunctivitis

PURPOSE OF REVIEW

Chemokines are a large group of low molecular weight cytokines that attract and activate leukocytes throughout the body and therefore have a key role in the framework of late-phase allergic responses. The purpose of this article is to provide an overview of the main chemokines involved in allergic conjunctivitis, their primary functions and their physiological roles, and therapies targeted at chemokines and their receptors for ocular allergic diseases.

RECENT FINDINGS

In recent years, there have been considerable advances in the understanding of ocular pathophysiology of ocular surface inflammatory diseases including both allergic eye diseases and dry eye syndrome. Several therapies being developed for dry eye inflammation are recognized as possible therapies for ocular allergic diseases as there are often common chemokines involved in both disease spectra.

SUMMARY

Chemokines represent an integral part of the late-phase cascade of ocular allergic inflammation. A deep understanding of specific chemokines and their interactions will help in targeting therapies to effectively manage ocular clinical findings and symptoms of allergic eye disease.

Management of vernal keratoconjunctivitis in children in Saudi Arabia

Vernal keratoconjunctivitis is a chronic inflammatory disease of the ocular surface and one of the worst types of allergic conjunctival diseases. Because of its chronic nature, it can damage the cornea, resulting in sight-threatening complications if left untreated. The disease affects mainly young children starting around the age of 7 years. We used keywords to search for published English articles in PUBMED, Google Scholar, EMBASE, and Cochrane Database of Systematic Reviews. Most of the published literature is focusing on general management of the disease and few publications focusing on treatment in the pediatric age group. We highlight the importance of how is the topical management differs between age groups. We focused on the importance of doing cycloplegic refraction for each child as the risk of keratoconus and oblique astigmatism is high in these cases. Furthermore, we highlight the importance of using eye lubricants as a therapeutic and preventive tool for the attacks of the disease. We highlight that most of the recent effective medications (especially the off-label ones) are not available in Saudi Arabia, such as tacrolimus, and some are only available to be prepared in tertiary center pharmacies as Cyclosporine A with higher concentrations.

Vernal Keratoconjunctivitis: an update focused on clinical grading system

INTRODUCTION

Vernal keratoconjunctivitis (VKC) is a severe disease with a prevalence of < 1 case out of 10,000 in Europe, which occurs mainly in pediatric age and is characterized by a severe and often bilateral chronic inflammation of the ocular surface. The diagnosis is generally confirmed by the finding at the ocular examination of conjunctival hyperemia, papillary hypertrophy in the tarsal conjunctiva, giant papillae, papillae in the limbus region.

OBJECTIVE

Aim of this review is to provide an updated overview on the disease focused on clinical grading system, searching papers published in the last decade on VKC in scientific databases.

RESULTS

Currently there are no standardized criteria for diagnosis of VKC and there is no uniformity to define disease severity, which makes difficult to diagnose and treat the disease.

CONCLUSIONS

Given the wide overlap of the symptoms of VKC with the allergic conjunctivitis, criteria of probable, possible or improbable diagnosis are needed, providing pediatricians with parameters useful for deciding whether to drive the patient to the ophthalmologist for diagnostic confirmation.

Tear cytokine profiling in patients with superior limbic keratoconjunctivitis who underwent medical treatment or in conjunction with surgical management

Purpose

To determine the correlation between superior limbic keratoconjunctivitis (SLK) and selected tear cytokines and to evaluate the efficacy of these cytokines in monitoring the response of patients with SLK to either medical treatment alone or in combination with conjunctival resection.

Design

A cohort study.

Methods

Twenty-five eyes of 13 patients with SLK were assigned to either medically responsive or surgical treatment groups depending on their responses 1 month after initial medical treatment. Treatment efficacy was assessed by improvements in clinical grading and decreases in the levels of tear cytokines.

Results

Fourteen eyes were improved by medical treatment alone, whereas satisfactory outcomes were achieved for the remaining 11 eyes after surgical management. The overall grading prior to medical treatment was lower in medically responsive group compared with surgical treatment group (p=0.0139). Among the examined tear cytokines, monocyte chemoattractant protein (MCP)-1 was positively associated with the severity of clinical grading (p=0.0251). While both treatments significantly decreased the levels of MCP-1 and interleukin-6, surgical treatment also decreased the levels of interferon-γ and tumour necrosis factor-α. Notably, overall cytokine levels after surgical treatment were lower than those after medical treatment alone.

Conclusions

Since an association of tear MCP-1 level with the clinical grading and treatment response of SLK was observed in this study, tear MCP-1 may be a potential indicator of SLK disease severity. According to the degree to which the tear cytokine levels were decreased, surgical treatment appears to be an effective treatment modality for patients with SLK who are refractory to medical treatment alone.

Clinical Usefulness of Monitoring Expression Levels of CCL24 (Eotaxin-2) mRNA on the Ocular Surface in Patients with Vernal Keratoconjunctivitis and Atopic Keratoconjunctivitis

Purpose. This study aimed to evaluate the clinical efficacy of using expression levels of CCL24 (eotaxin-2) mRNA on the ocular surface as a biomarker in patients with vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). Methods. Eighteen patients with VKC or AKC (VKC/AKC group) and 12 control subjects (control group) were enrolled in this study. The VKC/AKC clinical score was determined by objective findings in patients by using the 5-5-5 exacerbation grading scale. All subjects underwent modified impression cytology and specimens were obtained from the upper tarsal conjunctiva. Expression levels of CCL24 (eotaxin-2) mRNA on the ocular surface were determined using real-time reverse transcription polymerase chain reaction. Results. The VKC group was divided into two subgroups, depending on the clinical score: the active stage subgroup with 100 points or more of clinical scores and the stable stage subgroup with 100 points or less. CCL24 (eotaxin-2) mRNA expression levels in the active VKC/AKC stage subgroup were significantly higher than those in the stable VKC/AKC subgroup and the control group. Clinical scores correlated significantly with CCL24 (eotaxin-2) mRNA expression levels in the VKC group. Conclusions. CCL24 (eotaxin-2) mRNA expression levels on the ocular surface are a useful biomarker for clinical severity of VKC/AKC.

Secondary allergic T cell responses are regulated by dendritic cell-derived thrombospondin-1 in the setting of allergic eye disease

Allergic eye disease, as in most forms of atopy, ranges in severity among individuals from immediate hypersensitivity to a severe and debilitating chronic disease. Dendritic cells play a key role in stimulating pathogenic T cells in allergen re-exposure, or secondary responses. However, molecular cues by dendritic cells underpinning allergic T cell response levels and the impact that this control has on consequent severity of allergic disease are poorly understood. Here, we show that a deficiency in thrombospondin-1, a matricellular protein known to affect immune function, has subsequent effects on downstream T cell responses during allergy, as revealed in an established mouse model of allergic eye disease. More specifically, we demonstrate that a thrombospondin-1 deficiency specific to dendritic cells leads to heightened secondary T cell responses and consequent clinical disease. Interestingly, whereas thrombospondin-1-deficient dendritic cells augmented activity of allergen-primed T cells, this increase was not recapitulated with naïve T cells in vitro. The role of dendritic cell-derived thrombospondin-1 in regulating secondary allergic T cell responses was confirmed in vivo, as local transfer of thrombospondin-1-sufficient dendritic cells to the ocular mucosa of thrombospondin-1 null hosts prevented the development of augmented secondary T cell responses and heightened allergic eye disease clinical responses. Finally, we demonstrate that topical instillation of thrombospondin-1-derived peptide reduces T cell activity and clinical progression of allergic eye disease. Taken together, this study reveals an important modulatory role of dendritic cell-derived thrombospondin-1 on secondary allergic T cell responses and suggests the possible dysregulation of dendritic cell-derived thrombospondin-1 expression as a factor in allergic eye disease severity.

Chemokine (C-C motif) ligand 2 and chemokine (C-C motif) ligand 7 in angle-closure glaucoma

PURPOSE

To compare the concentrations of chemokine (C-C motif) ligand 2 (CCL2) and chemokine (C-C motif) ligand 7 (CCL7) in aqueous humour of eyes with acute primary angle-closure (APAC), primary angle-closure glaucoma (PACG) or with age-related cataract.

METHODS

The prospective investigation included a study group of 56 patients (24 patients with APAC; 32 patients with PACG) undergoing glaucoma surgery and a control group of 21 patients undergoing routine cataract surgery. The interval between glaucoma attack and trabeculectomy was 19.4 ± 9.8 days.

RESULTS

The concentrations of CCL2 (3037 ± 501 versus 1127 ± 141 pg/ml; p = 0.003) and CCL7 (10.5 ± 2.4 versus 2.8 ± 0.4 pg/ml; p < 0.001) were significantly higher in the APAC group than in the PACG group, while the concentrations of both cytokines did not differ significantly between the PACG group and the control group (CCL2: 1190 ± 98 pg/ml; p = 0.10; CCL7: 2.0 ± 0.6; p = 0.18). The concentrations of both cytokines were significantly and inversely correlated with the interval between the acute angle-closure attack and surgery (CCL2: p = 0.02; ρ = -0.48; CCL7: p = 0.04; ρ = -0.42). Higher CCL2 concentrations were associated with higher prevalence of surgical failure (28.6% versus 7.1%; p = 0.036).

CONCLUSIONS

Concentrations of CCL2 and CCL7 as major inflammatory cytokines with potential influence on the risk of filtering surgery failure were significantly elevated after an acute glaucoma attack and decreased with longer interval to the attack. Trabeculectomy may have a lower risk of failure if performed later than earlier after an acute glaucoma attack, with lower CCL2 concentrations associated with better surgical outcome.

Total IgE and eotaxin (CCL11) contents in tears of patients suffering from seasonal allergic conjunctivitis

Background

To prospectively investigate patients with seasonal allergic conjunctivitis (SAC) during the pollen season and test associations between tears total IgE, eotaxin concentrations, and SAC severity.

Methods

Enrolled patients presented ocular symptoms and clinical signs of SAC at the time of presentation. Ocular itching, hyperaemia, chemosis, eyelid swelling, and tearing were scored, and the sum of these scores was defined as the clinical score. Conjunctival papillae were separately graded. We measured eotaxin concentration in tears by an enzyme-linked immunosorbent assay (ELISA) and total tear IgE by Lacrytest strip.

Results

Among thirty patients (30 eyes), 11 showed neither tear IgE nor tear eotaxin, while 15 out of 19 patients with positive IgE values presented a positive amount of eotaxin in their tears (Fisher’s test: p < 0.001). The mean eotaxin concentration was 641 ± 154 (SEM) pg/ml. In patients with no amount of tear IgE, we observed a lower conjunctival papilla grade than in patients whose tears contained some amount of IgE (trend test: p = 0.032). In the 15 patients whose tear eotaxin concentration was null, tear IgE concentration was 5.3 ± 3.5 arbitrary units; in the other 15 patients whose eotaxin was positive, IgE reached 21 ± 4.3 arbitrary U (Mann–Whitney: p < 0.001). We measured 127 ± 47 pg/ml eotaxin in patients with no history of SAC but newly diagnosed as suffering from SAC, and 852 ± 218 pg/ml eotaxin in patients with a known SAC (p = 0.008). In contrast, tear IgE concentrations of both groups did not differ statistically significantly (p = 0.947).

Conclusions

If IgE and eotaxin secreted in tears are major contributors in SAC pathogenesis, they however act at different steps of the process.

Mapracorat, a selective glucocorticoid receptor agonist, causes apoptosis of eosinophils infiltrating the conjunctiva in late-phase experimental ocular allergy

Background

Mapracorat, a novel nonsteroidal selective glucocorticoid receptor agonist, has been proposed for the topical treatment of inflammatory disorders as it binds with high affinity and selectivity to the human glucocorticoid receptor and displays a potent anti-inflammatory activity, but seems to be less effective in transactivation of a number of genes, resulting in a lower potential for side effects. Contrary to classical glucocorticoids, mapracorat displays a reduced ability to increase intraocular pressure and in inducing myocilin, a protein linked to intraocular pressure elevation. Allergic conjunctivitis is the most common form of ocular allergy and can be divided into an early phase, developing immediately after allergen exposure and driven primarily by mast cell degranulation, and a late phase, developing from 6–10 hours after the antigen challenge, and characterized by conjunctival infiltration of eosinophils and other immune cells as well as by the production of cytokines and chemokines.

Methods

In this study, mapracorat was administered into the conjunctival sac of ovalbumin (OVA)-sensitized guinea pigs 2 hours after the induction of allergic conjunctivitis, with the aim of investigating its activity in reducing clinical signs of the late-phase ocular reaction and to determine its mechanism of anti-allergic effects with respect to apoptosis of conjunctival eosinophils and expression of the chemokines C-C motif ligand 5 (CCL5), C-C motif ligand 11 (CCL11), and interleukin-8 (IL-8) and the proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α).

Results

Mapracorat, administered into the conjunctival sac of OVA-sensitized guinea pigs 2 hours after allergen exposure, was effective in reducing clinical signs, eosinophil infiltration, and eosinophil peroxidase activity in the guinea pig conjunctiva; furthermore, it reduced conjunctival mRNA levels and protein expression of both CCL5 and CCL11. Mapracorat was more effective than dexamethasone in increasing, in conjunctival sections of OVA-treated guinea pigs, apoptotic eosinophils.

Conclusion

Mapracorat displays anti-allergic properties in controlling the late phase of ocular allergic conjunctivitis and is a promising candidate for the topical treatment of allergic eye disorders.

New twists to an old story: novel concepts in the pathogenesis of allergic eye disease

The prevalence of allergy is rising globally at a very significant rate, which is currently at 20-40% of individuals in westernized nations. In the eye, allergic conditions can take on the acute form such as in seasonal and perennial allergic conjunctivitis, or a more severe and debilitating chronic form such as in vernal and atopic keratoconjunctivitis. Indeed, some key aspects of allergic eye disease pathophysiology are understood, such as the role of mast cells in the acute allergic reaction, and the contribution of eosinophils in late-onset and chronic allergy. However, recent developments in animal models and clinical studies have uncovered new and important roles for previously underappreciated players, including chemokine receptors on ocular surface dendritic cells such as CCR7, the contribution of conjunctival epithelium to immunity, histamine and leukotriene receptors on conjunctival goblet cells and a role for mast cells in late-onset manifestations. Furthermore, recent work in animal models has delineated the contribution of IL-4 in the increased incidence of corneal graft rejection in hosts with allergic conjunctivitis. Recent studies such as these mean that conventional paradigms and concepts should be revisited. The aim of this review is to highlight some of the most recent advances and insights on newly appreciated players in the pathogenesis of allergic eye disease.

Differential chemokine expression in chronic GVHD of the conjunctiva

In chronic GVHD after BMT, the conjunctiva represents a target organ. GVHD can lead to severe inflammation and dry-eye syndrome (sicca syndrome). The molecular mechanisms are largely unknown. We examined the expression of chemokines in the conjunctiva in cases of chronic GVHD. In this study, we included 10 patients with chronic GVHD and 10 healthy controls. Clinical data were collected and tear film analysis and conjunctival cytology were carried out. Conjunctival biopsies were taken from all participants. Gene expression profiles of chemokines and their corresponding receptors were evaluated by means of quantitative real-time PCR. Chemokine protein expression was analysed by immunohistochemical analyses. Expressions of the Th1-associated chemokines, chemokine (C-X-C motif) ligand (CXCL) 9 (Mig), CXCL10 (IP-10), and their receptor chemokine (C-X-C motif) receptor 3 (CXCR3) were significantly increased in GVHD patients. Immunohistochemical analysis confirmed marked expression of the inflammatory CXCR3 ligands. A total of six patients had a moderate or severe sicca syndrome. Impression cytology revealed a mild keratinisation, moderate keratinisation or severe squamous metaplasia in three patients, respectively. Chronic GVHD of the conjunctiva is characterised by the expression of Th1-associated chemokines. Taken together, our results confirm that the conjunctiva is a target organ in this T cell-mediated process and add to molecular understanding of conjunctival GVHD.

Immune mechanisms in allergic eye diseases: what is new?

PURPOSE OF REVIEW

The purpose of this review will be to focus on new findings that expand our understanding of the immune mechanisms occurring in the various forms of allergic eye disease and in experimental models, and some novel therapeutic approaches.

RECENT FINDINGS

The novel data encompass three main areas: effector mechanisms in allergic eye disease; cytokines and chemokines in conjunctival responses; combinations of drugs for improving treatment options for allergic eye disease.

SUMMARY

The term 'allergic eye disease' describes a spectrum of clinical conditions, ranging from the common, milder conditions of seasonal and perennial allergic conjunctivitis (SAC, PAC), to the rare and more severe diseases, vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). These latter two diseases can involve the cornea, leading to impaired vision. Although there is an underlying allergic mechanism, each of these ocular surface conditions involves different cellular responses and much effort has been made to identify the molecular pathways, which could be used as potential targets for therapeutic intervention. Currently available drugs, in particular for chronic forms of disease, are inadequate and there is an urgent need for safer, more localized and effective treatment.

Evaluation of eotaxin-1, -2, and -3 protein production and messenger RNA expression in patients with vernal keratoconjunctivitis

PURPOSE

To evaluate the in vivo expression of members of the eotaxin subfamily, eotaxin-1, -2, and -3, at the ocular surface, we analyzed the messenger RNA (mRNA) expression of the eotaxin subfamily in conjunctival epithelium and the protein expression of the eotaxin subfamily in tears of patients with vernal keratoconjunctivitis (VKC) and in those of healthy individuals.

METHODS

The subjects were 25 patients with VKC (25 eyes) and 11 healthy volunteers (11 eyes) as a control. Tear samples were collected using the Schirmer strip method. Tear samples were eluted, and concentrations of eotaxin-1, -2, and -3 in the tear samples were determined by enzyme-linked immunosorbent assay (ELISA). Concentration of eosinophil cationic protein (ECP) in tears was also determined by chemiluminescent enzyme immunoassay. Conjunctival epithelial cells were obtained from upper tarsal conjunctiva by impression cytology, and eotaxin-1, -2, and -3 mRNA extracted from the impression cytology membrane were analyzed by reverse transcriptase polymerase chain reaction (RT-PCR). Conjunctival smears, which were obtained by tarsal conjunctival scraping, were stained for eotaxin-2 using immunohistochemical methods.

RESULTS

In the ELISA analysis, the expression ratio of eotaxin-1 (P < 0.01) and -2 (P < 0.001) in tears was significantly higher in the VKC group than in the control group. Concentrations of eotaxin-1 and -2 in tears in the VKC group were 0.7 and 1440.5 (median values) pg/ml, respectively. In the VKC group, the concentration of eotaxin-2 in tears was higher than that of eotaxin-1. There was a significant correlation between the concentration of eotaxin-2 and that of ECP in tears in the VKC group (r = 0.53, P < 0.01). Expression of eotaxin-3 protein in tears was not detected in the VKC group or the controls. In the RT-PCR analysis, the positive ratio of eotaxin-1, -2, and -3 mRNA expression in the VKC group was significantly higher than that in the control group (P < 0.01, P < 0.01, P < 0.05, respectively). In the immunohistochemical analysis, positive staining was detected in epithelial-like cells in conjunctival smears obtained from the patients with VKC.

CONCLUSIONS

We showed that the mRNA expression and the protein production of the eotaxin subfamily at the ocular surface are critical biomarkers when investigating the pathophysiology of eosinophilic inflammation and the effect of antiallergic treatment in patients with VKC.

Vernal keratoconjunctivitis: a major review

Vernal keratoconjunctivitis (VKC) is a chronic, bilateral, at times asymmetrical, seasonally exacerbated, allergic inflammation of the ocular surface, involving tarsal and/or bulbar conjunctiva. Though the allergic nature of this entity has been accepted for a long time, the accumulation of a large amount of immunological data has proved that the pathogenesis of VKC is much more complex than a mere type 1 hypersensitivity reaction. In the past several years, many clinical and experimental studies about the cells and mediators involved in initiating and perpetuating the ocular allergic inflammation have shown that T helper type 2 cells and their cytokines, corneal fibroblasts and epithelium along with various growth factors play an important role in the pathogenesis of VKC. Based on this information about the pathogenesis of VKC newer, more selective drugs like anti-chemokine receptor antibodies and leukotriene receptor antagonists are under evaluation. Cyclosporine has been shown to be effective in the treatment of VKC but further randomized control trials are required to establish the minimum effective concentration.

Prostaglandin E receptor subtype EP3 in conjunctival epithelium regulates late-phase reaction of experimental allergic conjunctivitis

BACKGROUND

We previously demonstrated that the prostaglandin E(2) (PGE(2))-EP3 pathway negatively regulates allergic reactions in a murine allergic asthma model.

OBJECTIVES

We investigated whether the PGE(2)-EP3 pathway also regulates the development of murine experimental allergic conjunctivitis (EAC).

METHODS

The expression of EP3 was examined by means of RT-PCR and immunohistochemistry in wild-type mice, as well as by means of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining in mice deficient in EP3 (Ptger3(-/-) mice) carrying the beta-galactosidase gene at the EP3 gene locus. EAC was induced by immunization of mice with short ragweed pollen (RW), followed by challenge with eye drops of RW, and eosinophil infiltration and eotaxin-1 mRNA expression in the conjunctiva were examined. Mice were also treated with a topical application of an EP3-selective agonist during the elicitation phase. Quantitative RT-PCR was used to detect expression of COXs and prostaglandin E synthases, and ELISA was used to measure PGE(2) production in the eyelid.

RESULTS

EP3 was constitutively expressed in conjunctival epithelium on the ocular surface. Ptger3(-/-) mice demonstrated significantly increased eosinophil infiltration in conjunctiva after RW challenge compared with wild-type mice. Consistently, significantly higher expression of eotaxin-1 mRNA was observed in Ptger3(-/-) mice. Conversely, treatment of wild-type mice with an EP3-selective agonist resulted in a significant decrease in eosinophil infiltration, which was blunted in Ptger3(-/-) mice. Expression of COX-2 and prostaglandin E synthases was upregulated and PGE(2) content was increased in the eyelids after RW challenge.

CONCLUSION

These data suggest that PGE(2) acts on EP3 in conjunctival epithelium and downregulates the progression of EAC.

Cytokine responses by conjunctival epithelial cells: an in vitro model of ocular inflammation

OBJECTIVES

We examined the differential secretion of cytokines by a conjunctival epithelial cell line in response to proinflammatory cytokines to identify the potential contributions during ocular surface inflammation.

METHODS

A conjunctival epithelial cell line was exposed to IFN-gamma, TNF-alpha, IL-4, or IL-13, and cytokine production was determined in supernatants at different times after exposure. Cell apoptosis was measured by flow cytometry.

RESULTS

TNF-alpha induced the greatest effect on cytokine secretion, which was time-dependent. TNF-alpha-stimulated secretion of IL-12p40 was significantly increased by 30 min; GM-CSF, MCP-1, IL-6, IL-7, IL-8, and RANTES were significantly increased by 2 h, and IFN-gamma and IL-1alpha by 24 h. After 48 h, TNF-alpha also induced a significant increase in IL-1beta, IL-3, and IP-10 secretion. IFN-gamma significantly enhanced IP-10 and RANTES secretion after 48 h of exposure. Following IL-4 treatment there was a significant increase in eotaxin-1 after 24h, and IL-12p40 and IL-3 after 48 h. IL-13 significantly increased the secretion of eotaxin-1 after 24 h, and IL-8 after 48 h.

CONCLUSION

Our results suggest that conjunctival epithelial cells are an important source of cytokines and chemokines that are regulated by proinflammatory cytokines and may play an important role in ocular surface inflammation.

Immunohistochemical findings in prosthesis-associated giant papillary conjunctivitis

PURPOSE

To identify functional subsets of inflammatory cells and expression of cytokines in the conjunctiva of patients with ocular prosthesis-associated giant papillary conjunctivitis (P-GPC).

METHODS

Specific immunohistochemical staining using monoclonal antibodies was performed on biopsy specimens obtained from superior tarsal conjunctiva of 18 patients with P-GPC. The prosthetic eyes were taken as the study group, whereas their fellow eyes were used as matched controls.

RESULTS

In normal conjunctiva, mast cells (MCs) were located only in the substantia propria (SP), whereas in P-GPC eyes MCs were also notable in the epithelium in five specimens. Tryptase-chymase-positive MCs (MC(TC)) were predominant both in P-GPC (79%) and in fellow (72%) eyes. MC(TC), CD4(+) lymphocyte, CD8(+) lymphocyte and eosinophil numbers were higher in P-GPC specimens compared with the fellow eyes (P = 0.005, 0.074, 0.012 and 0.025, respectively). Eosinophils were detected in 58.8% of P-GPC specimens and 16.7% of control specimens (P = 0.053). The number of inflammatory cells expressing eotaxin and interleukin (IL)-4 was higher in P-GPC group (P = 0.050 and 0.048, respectively). Nine out of 17 giant papillary conjunctivitis specimens (52.9%) showed eotaxin and IL-4 immunoreactivity, which was considerably higher than the fellow eyes (16.7%) (P = 0.064).

CONCLUSION

These findings suggest that P-GPC is an allergic disease of the eye associated with increased numbers of MC, eosinophils and lymphocytes in the conjunctiva and a remarkable expression of IL-4 and eotaxin both by the conjunctival epithelium and by the inflammatory cells in the SP.

Elevated tear fluid levels of MIP-1alpha in patients with cystic fibrosis

Cystic fibrosis (CF) is the commonest multisystem genetic disease of white races, caused by mutations in the cystic fibrosis transmembrane regulator (CFTR), encoded on the long arm of chromosome 7. Mutations in the CFTR gene result in defective sodium, chloride, and water transport in the epithelial cells of the respiratory, hepatobiliary, gastrointestinal, and reproductive tracts, the pancreas, and the eye. The pathogenesis of ocular changes in CF is still unknown, but CF belongs to the large pathologic group of ocular surface epithelial diseases, termed keratoconjunctivitis sicca (KCS), that develop in dry eye syndrome. The aim of this study was to evaluate the levels of macrophage inflammatory protein-1alpha (MIP-1alpha) in the tear fluid of CF patients. We also investigated the correlation between the tear levels of this chemokine and clinical severity of CF and ocular surface disease. We studied 25 patients with CF with a mean age of 14 years. Chemokine levels were determined by ELISA. Complete ophthalmic examination, including dry eye tests, were used to study the ocular surface. The tear levels of MIP-1alpha in the CF patients were significantly higher when compared with healthy controls. We found a negative correlation between the tear levels of MIP-1alpha and clinical severity in CF patients and a positive correlation between the tear levels of MIP-1alpha and the presence of dry eye findings in CF patients. This current study indicates that chemokines play an important role in the ongoing inflammatory response. Our findings may help to explain one of the key factors contributing to the pathogenesis of ocular surface changes in CF patients.

Increased serum levels of CXCL8 chemokine in acute toxoplasmic retinochoroiditis

PURPOSE

Chemokines have been implicated in the control of leucocyte infiltration in uveitis and in modulating angiogenesis in several ocular conditions. Toxoplasmic retinochoroiditis is a common cause of posterior uveitis. This study aimed to evaluate the serum concentrations of CC and CXC chemokines in patients with acute toxoplasmic retinochoroiditis.

METHODS

The levels of five chemokines (CCL2, CCL11, CXCL9, CXCL8 and CXCL10) were evaluated in the serum of patients with active toxoplasmic retinochoroiditis (n = 55) and control subjects (n = 40). In a subset of patients (n = 18), a second measure of serum levels of chemokines was performed after the completion of oral treatment with pyrimethamine (25 mg/day), sulphadiazine (1 g, four times per day), folinic acid (7.5 mg/day) and prednisone (initial dose: 1 mg/kg/day) for approximately 30 days.

RESULTS

Patients with toxoplasmic retinochoroiditis, notably those presenting with vasculitis, had increased serum levels of CXCL8 (mean +/- standard error of the mean [SEM] 35.1 +/- 6.5 pg/ml) compared with control subjects (mean +/- SEM 16.0 +/- 2.3 pg/ml; p = 0.01). There were no differences between patients and controls in serum levels of the other chemokines measured. The size of ocular lesions correlated significantly with serum levels of CXCL8 and CXCL9. After treatment, there was a significant reduction in serum levels of CXCL8. Severity of vitreous opacities did not correlate with serum levels of these chemokines.

CONCLUSIONS

These data suggest a role for CXCL8 in the inflammatory process of acute toxoplasmic retinochoroiditis. Furthermore, CXCL8 may be a useful marker for patient follow-up.

Multiple cytokines in human tear specimens in seasonal and chronic allergic eye disease and in conjunctival fibroblast cultures

BACKGROUND

Several cytokines are involved in the recruitment and activation of inflammatory cells in ocular allergic diseases. The purpose of the study was to assay multiple cytokines and chemokines in tears, to compare subgroups of allergic conjunctivitis (AC) with controls, and in culture supernatants to determine whether conjunctival fibroblasts produce some of these cytokines.

METHODS

Fifty to one hundred microlitre tears were obtained from patients with active seasonal allergic conjunctivitis (SAC; n=12), vernal keratoconjunctivitis (VKC; n=18), atopic keratoconjunctivitis (AKC; n=6) and non-atopic controls (n=14). Primary conjunctival fibroblasts grown in vitro were stimulated with IL-4, IL-13 or TNF-alpha for 24 h. Cell-free tear and culture supernatants were assayed for IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IFN-gamma, TNF-alpha, eotaxin, MCP-1 and RANTES using multiplex bead analysis. Induction of chemokine gene expression was determined by PCR.

RESULTS

IL-1beta, IL-2, IL-5, IL-6, IL-12, IL-13, MCP-1 were increased in all tears groups compared with controls, with highly significant correlations between many of these molecules. In addition IL-4, IFN-gamma, and IL-10 were elevated in SAC and VKC, while eotaxin and TNF-alpha were only increased in VKC. IL-6, IL-8, MCP-1, RANTES and eotaxin were detected from fibroblasts cultures, and were all up-regulated by TNF-alpha. By PCR, fibroblasts expressed MCP-1 transcripts constitutively, whereas IP-10 and Mig were up-regulated by TNF-alpha.

CONCLUSIONS

Differential cytokine levels support tears as a useful indicator of immune mechanisms occurring during AC. The striking similarities in chemokine profiles between tears and fibroblasts suggest these cells as likely sources of chemokines in tears.

Antibody Array-Generated Cytokine Profiles of Tears of Patients with Vernal Keratoconjunctivitis or Giant Papillary Conjunctivitis

PURPOSE

To investigate differences in the cytokine and chemokine profiles of patients with vernal keratoconjunctivitis (VKC) or giant papillary conjunctivitis (GPC).

METHODS

The study included six patients (six eyes) with VKC, five patients (five eyes) with GPC, and five healthy volunteers (five eyes) as controls. None of the patients had received any anti-allergic treatment prior to this study. One patient with VKC was given a tear examination to evaluate the effect of anti-inflammatory treatment with a steroid on the tear cytokine profile about the treatment. Tear samples were collected with the Schirmer I method, using filter paper. Tear samples were eluted and analyzed by an antibody array system for inflammation-related factors, including cytokines and chemokines.

RESULTS

In the patients with VKC, four inflammation-related factors, eotaxin, interleukin (IL)-11, monocyte chemoattractant protein (MCP)-1, and macrophage-colony stimulating factor (M-CSF) increased to four times the values in the control group, and seven inflammation-related factors, eotaxin-2, IL-4, IL-6, interleukin-6 soluble receptor (IL-6sR), IL-7, macrophage inflammatory protein (MIP)-1delta, and tissue inhibitor of metalloproteinases (TIMP)-2, increased to eight times the control values. In the patients with GPC, three inflammation-related factors, IL-6, M-CSF, and monokine-induced gamma interferon (MIG), increased to four times those in the control group, and five inflammation-related factors, eotaxin-2, IL-6sR, IL-11, MIP-1delta, and TIMP-2, increased to eight times the control values. The increase in IL-6sR relative to the controls was statistically significant in both the VKC and GPC groups. The increase in eotaxin-2 was significant only in the VKC group, and that in TIMP-2 was significant only in the GPC group, compared with the controls.

CONCLUSIONS

The present study demonstrated the presence of crucial cytokines, soluble cytokine receptors, and chemokines in tears of patients with VKC and GPC. In particular, IL-6sR increased significantly in both the VKC and GPC groups, whereas eotaxin-2 increased significantly only in the VKC group. Thus, IL-6sR may play an important pathophysiological role in giant papillary proliferation in VKC and GPC, and eotaxin-2 may play an important role in eosinophilic inflammation in VKC.

Case series of 406 vernal keratoconjunctivitis patients: a demographic and epidemiological study

PURPOSE

To evaluate the specific allergic sensitization and epidemiological characteristics of vernal keratoconjunctivitis (VKC).

METHODS

This retrospective non-comparative case series included 406 VKC patients. Data included patient and family histories, and results of allergic tests. Annual incidence and prevalence rates were calculated for a cohort of 128 VKC patients from the greater Padua area.

RESULTS

The great majority of VKC patients were male (76%), with a male : female ratio of 3.3 : 1. A skin prick test, specific serum IgE or conjunctival challenge was positive in 43%, 56% and 58% of patients, respectively. In the cohort of patients from the Padua area, the prevalence of the disease was 7.8/100,000, with a higher rate in young males (57/100,000) compared with young females (22/100,000), and lower rates in people over 16 years of age (3.8/100,000 in males, 1/100,000 in females). The incidence of VKC was 1/100,000, with a higher rate in males under 16 years of age (10/100,000) compared with females (4.2/100,000). In people over 16 years of age, the incidence of the disease was 0.06/100,000, with no difference between males and females.

CONCLUSION

An IgE-mediated sensitization was found in only half of the VKC patients. Vernal keratoconjunctivitis is not a rare event in the paediatric population but is an extremely rare new disease in adults.

Th1- and Th2-type cytokines in chronic ocular allergy

BACKGROUND

Previous reports have suggested that Th2-type cytokines are important in the pathogenesis of ocular allergic diseases. The purpose of this study is to measure levels and mRNA expression of Th1- and Th2-type cytokines in patients with active vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC).

METHODS

Tear samples and tear-isolated cells were obtained from 9 healthy participants (CT--controls), 28 VKC, and 6 AKC patients. IL-4, IL-13, and interferon gamma (IFNgamma) tear levels were determined by ELISA, and IL-4 and IFNgamma tear cell mRNA expression by RT-PCR. Effects of these cytokines on IL-6 and IL-8 secretion, and on ICAM-1 expression by conjunctival fibroblasts, were evaluated by ELISA and flow cytometry respectively.

RESULTS

Interleukin-4 tear levels were increased in VKC and AKC compared with CT, but only IFNgamma significantly correlated with corneal involvement. An IL-4/13-dominant profile was found in 50% of VKC and in 17% of AKC patients, while a IFNgamma-dominant profile was found in 18% of VKC and in 17% of AKC patients. IL-4 and IFNgamma transcripts were detected in tear cells from 11 out of 12 VKC patients. IFNgamma upregulated expression of ICAM-1 on conjunctival fibroblasts and the secretion of IL-6 and IL-8.

CONCLUSIONS

Although both IL-4 and IFNgamma are detected in tears, only IFNgamma levels correlated with disease severity and upregulated ICAM-1 on conjunctival fibroblasts, suggesting the role of IFNgamma in the inflammatory phase of chronic allergic eye diseases.

Basic science and pathophysiology of ocular allergy

Ocular allergy includes several clinical subtypes ranging from the mild seasonal allergic conjunctivitis to the potentially sight-threatening atopic keratoconjunctivitis. Current therapies, particularly for the severe forms of disease, need to be more localized and with fewer side effects. For this to be achieved, it requires a better understanding of the basic mechanisms involved. In this chapter, recent findings are discussed that suggest that it is important to take an integrated approach, including both immune and structural elements of the eye. This provides potential new strategies for therapy, addressing the influence of structural cells in disease. These might influence the immune processes that take place and, as the structural cells are precisely localized, topical application is likely to be effective.

Tear cytokines in acute and chronic ocular allergic inflammation

PURPOSE OF REVIEW

Elevated levels of inflammatory cytokines have been reported in tears from ocular allergic disease states. The purpose of this review is to assimilate recent research contrasting tear cytokine concentrations in non-allergic subjects versus subjects with acute (seasonal allergic conjunctivitis) and chronic (giant papillary conjunctivitis, vernal keratoconjunctivitis, atopic keratoconjunctivitis) ocular allergic inflammation to discover whether the cytokine profiles could provide useful insight into disease mechanisms and therapeutic targets.

RECENT FINDINGS

Recent studies have revealed distinct differences in the cytokine/chemokine concentrations in tears between the various manifestations of ocular allergy. The acute (seasonal allergic conjunctivitis) and iatrogenic (giant papillary conjunctivitis) forms of ocular allergic inflammation are characterized by an overall lack of significant cytokine changes in tears compared with chronic disease (vernal keratoconjunctivitis, atopic keratoconjunctivitis). Chronic ocular allergic inflammation produces increased concentrations of T helper 1 and 2, and proinflammatory cytokines as well as chemokines. However, vernal and atopic keratoconjunctivitis portray distinct differences in the patterns of tear cytokines/chemokines expressed.

SUMMARY

The plethora of increased cytokines and chemokines in vernal and atopic keratoconjunctivitis compared with non-allergic, seasonal allergic conjunctivitis and giant papillary conjunctivitis provides a new perspective into the complex inflammatory processes occurring on the ocular surface in chronic disease. The ability to measure multiple cytokines in tears, combined with knowledge obtained from in-vitro analysis of the individual and combined effects of these cytokines on various conjunctival cells (i.e. mast cells, epithelial cells, fibroblasts) has facilitated further understanding of specific processes contributing to maintenance of inflammation and progression of vision-threatening disease and paved the way toward new therapeutic targets.

Increased eotaxin in tears of patients wearing contact lenses

PURPOSE

Giant papillary conjunctivitis in patients wearing contact lenses occurs after intolerance and/or allergy to contact lenses. Eotaxin is a CC chemokine with a potent and specific chemotactic effect for eosinophils, which are involved in allergies. The purpose of this study is to measure the eotaxin levels in tears of patients wearing contact lenses and in normal subjects. Eotaxin levels were also correlated with the grade of giant papillary conjunctivitis.

METHODS

Around 10 microL of tears were collected with glass capillaries in 16 patients wearing contact lenses and in 10 normal volunteers. Giant papillary conjunctivitis was graded from 0 to 4 by reference to standard slit-lamp photographs of the superior tarsal conjunctiva. Eotaxin concentration in tears was measured by ELISA using mouse anti-human eotaxin monoclonal antibodies. For the statistical analysis of the results, the paired Wilcoxon/Kruskal-Wallis test was used.

RESULTS

The mean concentration of eotaxin was 2698+/-233 (SEM) pg/mL in patients wearing contact lenses and 1498+/-139 pg/mL in normal subjects. The difference was statistically significant (P=0.0004). The mean score of papilla grade was 1.75+/-0.19 in patients wearing contact lenses and 0.2+/-0.13 in normal subjects (P<0.0001). Papilla grade could be correlated to the eotaxin level in tears (R2=0.6562 and P<0.0001).

CONCLUSION

An increase of eotaxin levels in tears was measured in patients wearing contact lenses. Eotaxin levels correlated with the severity of giant papillary conjunctivitis. These data suggest that eotaxin could play a role in papilla formation.

Roles of Chemokines in Ocular Allergy and Possible Therapeutic Strategies

The mechanism of ocular surface allergy in the forms of atopic conjunctivitis and vernal keratoconjunctivitis has been highlighted by specific functions of chemokines. In the context of late-phase allergic responses, these molecules have key roles in recruitment and activation of leukocytes. Their interaction with ligands is redundantly regulated; however, results from strategies to block subsets of chemokines have revealed unexpected or highly organized roles of these mediators. Exemplified by analyses of CCL11 function, current concepts of ocular allergy support CCL11 as central mediator. We emphasize the functions as modulator of mast cell activation/differentiation. With the prospect of understanding these functions, new modalities of drugs specifically developed to target CCL11/CCR3 interaction have been discussed.

The role of chemokines and their receptors in ocular disease

The migration and infiltration of cells into the eye whether blood-borne leucocytes, endothelial or epithelial cells occurs in many ocular diseases. Dysregulation of this process is apparent in chronic inflammation, corneal graft rejection, allergic eye disease and other sight-threatening conditions. Under normal and inflammatory conditions, chemokines and their receptors are important contributors to cell migration. To date, 47 chemokines and 19 chemokine receptors have been identified and characterised. In recent years, investigations into the role of chemokines and their receptors in ocular disease have generated an increasing number of publications. In the eye, the best understood action of these molecules has arisen from the study of their ability to control the infiltration of leucocytes in uveitis. However, the involvement of chemokines in angiogenesis in several ocular conditions and in the survival of corneal transplants demonstrates the multifaceted nature of their effects. Interestingly, the constitutive expression of chemokines and their receptors in ocular tissues suggests that certain chemokines have a homeostatic function. In this review, we discuss the nature and function of chemokines in health and disease, and describe the role of chemokines in the pathogenesis of different ocular conditions.

Eotaxin-1 (CCL11) up-regulation in tears during seasonal allergic conjunctivitis

PURPOSE

To compare in-season eotaxin-1 levels in tears of patients suffering from seasonal allergic conjunctivitis (SAC) with (1) tears of normal subjects and (2) tears of SAC patients out of season.

METHODS

Tears of 11 SAC patients and six control volunteers were collected during the pollen season. Tears of five SAC patients showing a strong sensitivity to grass pollen (skin-prick tests and specific serum IgE) were collected both in season and out of season. ELISA measured eotaxin-1 level.

RESULTS

Eotaxin-1 concentration in tears of SAC patients [2,100+/-503 (SEM) pg/ml] and normal subjects (1,193+/-176 pg/ml) were significantly different (P=0.0049). Regarding allergic patients, the clinical score (sum of five allergic criteria) was significantly different in season and out of season (P=0.0043) as was also the case with eotaxin-1 concentration (P=0.024).

CONCLUSIONS

The eotaxin-1 concentration in tears of patients showing hay fever could confirm a diagnosis of seasonal ocular allergy.

The T-lymphocyte chemoattractant Mig is highly expressed in vernal keratoconjunctivitis

PURPOSE

To examine the expression of the three interferon-gamma-inducible CXCR3-binding chemokines, CXCL10/IP-10 (interferon-gamma-inducible protein of 10 KDa), CXCL9/Mig (monokine induced by interferon-gamma), and CXCL11/I-TAC (interferon-inducible T-cell alpha chemoattractant) in the conjunctiva of patients with vernal keratoconjunctivitis (VKC). These chemokines exhibit potent T-lymphocyte chemoattractant activity.

DESIGN

Immunohistochemical study.

METHODS

Conjunctival biopsy specimens from 16 patients with active VKC and nine control subjects were studied by immunohistochemical techniques using monoclonal antibodies directed against IP-10, Mig, and I-TAC. The phenotype of inflammatory cells expressing chemokines was examined by double immunohistochemistry.

RESULTS

In the normal conjunctiva, very weak Mig immunoreactivity was observed on basal epithelial cells and on vascular endothelial cells in the upper substantia propria. There was no immunoreactivity for the other chemokines. In all VKC specimens, strong immunoreactivity for Mig was expressed by epithelial cells, vascular endothelial cells, and inflammatory mononuclear cells. Inflammatory mononuclear cells expressing IP-10 and I-TAC were noted in 10 and nine specimens, respectively. The numbers of Mig(+) inflammatory cells were significantly higher than the numbers of IP-10(+) and I-TAC(+) inflammatory cells (P <.001). Inflammatory cells expressing Mig were CD4(+) T-helper/inducer cells (71.6 +/- 3.2%), CD8(+) T-cytotoxic/suppressor cells (19.5 +/- 1.5%), and CD68(+) monocytes/macrophages (5.3 +/- 5%). All inflammatory cells expressing IP-10 and I-TAC were CD68(+) monocytes/macrophages.

CONCLUSIONS

The CXC chemokine Mig is selectively and highly expressed in VKC suggesting a pathogenic role of the chemokine receptor CXCR3 and the ligand Mig in the recruitment of activated T lymphocytes.

Epithelial cells in ocular allergy

Conjunctival epithelial cells do not act only as mechanical barriers, preventing the entry of particles, bacteria, viruses, and noxious substances into the eye but they are also active participants in the regulation of allergic inflammation via expressing adhesion/effector molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, human leukocyte antigen-DR, CD40/CD40L, Fas/Fas ligand) on their surfaces and releasing numerous proinflammatory cytokines, such as eotaxin, regulated on activation normal T-cell expressed and released (RANTES), macrophage inflammatory protein-1, interleukin (IL)-8, IL-6, and tumor necrosis factor-a, which are necessary for the proliferation, differentiation, activation, and chemotaxis of various inflammatory cells into the conjunctiva. Histamine, released from the conjunctival mast cells, might stimulate the synthesis of proinflammatory molecules such as IL-6 and IL-8 by the epithelial cells through the receptors that couple to inositol phosphate generation and, therefore, amplify the allergic response. The relationship between the epithelium and allergy should be considered in detail in future studies aiming at an effective control and treatment of all forms of allergic conjunctivitis.

T-cell characterization in chronic allergic eye disease

Chronic allergic eye disease encompasses several disorders, but it is vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC) that have sight-threatening sequelae. T cells, eosinophils, and mast cells are all found in the conjunctiva, and are thought to play a role in disease pathogenesis. Recently, the conjunctival epithelium has also been considered to play a key role. New and effective therapeutic strategies for the future for these patients depend on achieving a greater understanding of the roles and interactions of the cell populations in these sight-threatening disorders.

Inhibitory effects of ketotifen on eotaxin-dependent activation of eosinophils: consequences for allergic eye diseases

BACKGROUND

The aim of this study was to investigate the effects of ketotifen on different parameters of human eosinophil functions, namely chemotaxis, oxidative metabolism and mediator release, induced after activation.

METHODS

Eosinophils from hypereosinophilic patients or normal donors were purified by Percoll gradient and the magnetic cell separation system. Chemotaxis was studied using the Boyden chamber technique using three potent chemoattractants: formyl-methionine-leucine-phenylalanine (fMLP), interleukin (IL)-5 and eotaxin. Oxidative metabolism was determined by a luminol-dependent chemiluminescence assay after activation with eotaxin or secretory immunoglobulin A (sIgA). The release of eosinophil cationic protein (ECP) and eosinophil derived neurotoxin (EDN) was measured by radioimmunoassay after activation with sIgA.

RESULTS

At pharmacologically active concentrations and in a dose-dependent manner, ketotifen significantly inhibited the chemotaxis of eosinophils to fMLP, IL-5 and eotaxin. The production of reactive oxygen species induced by eotaxin and sIgA was decreased by ketotifen, showing a more pronounced effect when cells were activated by eotaxin. Activation by sIgA resulted in ECP and EDN release, which was partially inhibited by ketotifen.

CONCLUSIONS

Through inhibition of chemotaxis, ketotifen might limit the number of eosinophils at the inflammation site during allergic reaction. Furthermore, inhibition by ketotifen of main inflammatory mediators release suggests a potential role of the drug in limiting the pathological potential of eosinophils.

Tear and mucus eotaxin-1 and eotaxin-2 in allergic keratoconjunctivitis

OBJECTIVE

Eotaxin-1 and eotaxin-2 are potent eosinophil chemotactic and activating peptides that may be implicated in the pathogenesis of the chronic allergic eye diseases vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). The purpose of this study was to measure these chemokines in tear and mucus samples of active-disease patients and in vitro cultured conjunctival epithelial cells and fibroblasts.

DESIGN

Comparative, observational case series and in vitro study.

PARTICIPANTS

Sixteen patients with clinically active and untreated VKC or AKC, six age-matched control patients, and five nonactive seasonal allergic conjunctivitis patients.

METHODS

Tears were collected from the active VKC and AKC patients, and from the normal patients. Mucus was collected from six of these VKC patients. Tears were also collected from an additional five allergic patients after obtaining a positive reaction to conjunctival allergen challenge. Conjunctival epithelial cell and conjunctival fibroblast cultures were exposed to interleukin (IL)-4, IL-13, and tumor necrosis factor-alpha (TNF-alpha), or to combinations of these cytokines.

MAIN OUTCOME MEASURES

Levels of eotaxin-1 and eotaxin-2 in tears, mucus, and culture medium.

RESULTS

High levels of eotaxin-1 and eotaxin-2 were found in mucus of VKC patients, whereas only eotaxin-2 was found to have increased significantly in tears of VKC and AKC patients compared with those of normal patients. Mucus contained higher levels of chemokines than did tears. Both tear eotaxin-1 and eotaxin-2 were correlated significantly with the percent of eosinophils in tear fluid. Eotaxin-1 also was correlated significantly with the sum clinical score and corneal involvement in VKC patients. Conjunctival epithelial cells in culture did not produce eotaxin-1 or eotaxin-2, either at baseline or after cytokine exposure. Conjunctival fibroblasts produced eotaxin-1 only after exposure to IL-4, TNF-alpha, and the combination of IL-4 plus TNF-alpha or IL-13 plus TNF-alpha.

CONCLUSIONS

Eotaxin-1 and eotaxin-2 are implicated in eosinophil recruitment and in the pathogenesis of VKC and AKC. Cytokine-stimulated conjunctival fibroblasts may be one source of eotaxin-1 in severely allergic tissues.

The effect of ketotifen on inflammatory markers in allergic conjunctivitis: an open, uncontrolled study

BACKGROUND

The efficacy and safety of ketotifen eye drop treatment in allergic conjunctivitis (AC) management is perfectly known by several studies, but the mechanism of action at the biochemical levels is poorly understood so we decided to perform an open, uncontrolled study in order to investigate the effect of the topical administration of ketotifen fumarate 0.05% on biochemical markers of inflammation on conjunctival cells in patients with AC.

METHODS

Nineteen patients with symptoms and signs of AC (itching, discharge, burning, redness, increase in the watery discharge, swelling and follicles) and with a history of allergy were prescribed with two daily instillation of one drop of eyewash ketotifen fumarate 0,05% in both eyes during thirty days. They were studied by measuring clinical and immunologic parameters.

RESULTS

Ketotifen fumarate treatment significantly reduced the total symptoms and signs score for each patient as well as each symptoms and signs at all time points compared with day 0 (p < 0.0001 and p < 0.016, respectively). Although the percentage of HLA-DR+ epithelial cells diminished only in 58% of patients, the numbers of CD29+ and eotaxin+ epithelial cells dropped significantly in 68% and 73 % of them (p < 0.0062 and <0.0082, respectively) as a consequence of the treatment. In 9 out of 19 patients a simultaneous decrease in the percentage of epithelial cells positive for CD29 and eotaxin was observed.

CONCLUSION

Ketotifen besides the well-known effect in reducing signs and symptoms of AC significantly diminished production of eotaxin and expression of CD29 by epithelial cells in patients with seasonal AC.

The CXC chemokine GCP-2/CXCL6 is predominantly induced in mesenchymal cells by interleukin-1beta and is down-regulated by interferon-gamma: comparison with interleukin-8/CXCL8

Human granulocyte chemotactic protein-2 (GCP-2)/CXCL6 is a CXC chemokine that functionally uses both of the IL-8/CXCL8 receptors to chemoattract neutrophils but that is structurally most related to epithelial cell-derived neutrophil attractant-78 (ENA-78)/CXCL5. This study provides the first evidence that GCP-2 protein is, compared with IL-8, weakly produced by some sarcoma, but less by carcinoma cells, and is tightly regulated in normal mesenchymal cells. IL-1beta was the predominant GCP-2 inducer in fibroblasts, chondrocytes, and endothelial cells, whereas IL-8 was equally well up-regulated in these cells by TNF-alpha, measles virus, or double-stranded RNA (dsRNA). In contrast, lipopolysaccharide (LPS) was a relatively better stimulus for GCP-2 versus IL-8 in fibroblasts. IFN-gamma down-regulated the GCP-2 production in fibroblasts induced by IL-1beta, TNF-alpha, LPS, or dsRNA. The kinetics of GCP-2 induction by IL-1beta, LPS, or dsRNA in fibroblasts differed from those of IL-8. Freshly isolated peripheral blood mononuclear leukocytes, which are a good source of IL-8 and ENA-78, failed to produce GCP-2. However, lung macrophages and blood monocyte-derived macrophages produced GCP-2 in response to LPS. Quantitatively, secretion of GCP-2 always remained inferior to that of IL-8, despite the fact that the ELISA recognized all posttranslationally modified GCP-2 isoforms. The expression of GCP-2 was confirmed in vivo by immunohistochemistry. The patterns of producer cell types, inducers and kinetics and the quantities of GCP-2 produced, suggest a unique role for GCP-2 in physiologic and pathologic processes.

The presence of chemokine (MCP-1, MIP-1alpha, MIP-1beta, IP-10, RANTES)-positive cells and chemokine receptor (CCR5, CXCR3)-positive cells in inflamed human gingival tissues

Chemokines are said to be small peptides that are chemoattractants for leukocyte subpopulations within local inflammation sites. Gingival inflammation is characterized by infiltration of inflammatory mononuclear cells. The point of this study was to examine the presence or absence of chemokine-positive cells and chemokine receptor-positive cells by means of immunohistochemical methods in samples of gingival tissues obtained from patients with marginal periodontitis. Macrophage chemotactic protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, (IFN-gamma)-inducible protein-10 (IP-10) and RANTES-producing cells were found to be present in inflamed human gingival tissues. In addition, CCR5- and CXCR3-positive cells were present. In contrast, no factor expression was observed in periodontally healthy gingival tissue. Our findings suggest that these chemokines may be responsible for modulating the process of infectious disease such as marginal periodontitis.

Expression of T lymphocyte chemoattractants and activation markers in vernal keratoconjunctivitis

BACKGROUND/AIMS

T lymphocytes are present in increased numbers in the conjunctiva of patients with vernal keratoconjunctivitis (VKC) and their activation has a central role in the pathogenesis of the chronic allergic inflammatory reactions seen in VKC. The aims of this study were to examine the expression of three recently described potent T lymphocyte chemoattractants, PARC (pulmonary and activation regulated chemokine), macrophage derived chemokine (MDC), and I-309, the MDC receptor CCR4, and T lymphocyte activation markers, CD25, CD26, CD62L, CD71, and CD30, and to correlate them with the counts of CD3(+) T lymphocytes in the conjunctiva of patients with VKC.

METHOD

Conjunctival biopsy specimens from 11 patients with active VKC, and eight control subjects were studied by immunohistochemical techniques using a panel of monoclonal and polyclonal antibodies directed against PARC, MDC, I-309, CCR4, CD25, CD26, CD62L, CD71, and CD30. The numbers of positively stained cells were counted. The phenotype of inflammatory cells expressing chemokines was examined by double immunohistochemistry.

RESULTS

In the normal conjunctiva, vascular endothelial cells in the upper substantia propria showed weak immunoreactivity for CD26. There was no immunoreactivity for the other antibodies. VKC specimens showed inflammatory cells expressing PARC, MDC, and I-309. The numbers of PARC(+) inflammatory cells were higher than the numbers of MDC(+) and I-309(+) inflammatory cells and the mean values of the three groups differed significantly (17.0 (SD 10.1); 9.5 (9.9), and 4.3 (7.9), respectively, p = 0.0117, ANOVA). The numbers of PARC(+) inflammatory cells had the strongest correlation with the numbers of CD3(+) T lymphocytes. Few CCR4(+) inflammatory cells were observed in only three specimens. Double immunohistochemistry revealed that all inflammatory cells expressing chemokines were CD68(+) monocytes/macrophages. The numbers of CD25(+) T lymphocytes were higher than the numbers of CD26(+), CD62L(+), CD71(+), and CD30(+) T lymphocytes and the mean values of the five groups differed significantly (46.2 (27.9), 30.7 (16.0), 20.1 (8.6), 7.8 (7.7), and 6.5 (4.0), respectively, p <0.001, ANOVA). The numbers of CD25(+) T lymphocytes had the strongest correlation with the numbers of CD3(+) T lymphocytes.

CONCLUSION

These results suggest a potential role for PARC, MDC, and I-309 in attracting T lymphocytes into conjunctiva in VKC. T lymphocytes in VKC are activated and express several activation markers which might contribute to the pathogenesis of VKC.