A Review of the Cytokine IL-17 in Ocular Surface and Corneal Disease.

Aim: To investigate the role of interleukin-17 in ocular surface and corneal disease. Ocular surface and corneal disease is a leading cause of blindness and is an ongoing challenge for the public health sector to implement effective therapies. The majority of cells in corneal lesions are derived primarily from neutrophils that induce inflammatory events that lead to tissue damage. One of the key pro-inflammatory cytokines is IL-17, and it has been investigated in order to facilitate the understanding of the pathogenesis of ocular surface lesion development. Method: A review of the literature was performed through a systematic approach. Results: IL-17 has been shown to exacerbate dry eye disease, viral and bacterial keratitis lesion severity, although it was found to be protective for Acanthamoeba. Antibodies developed to neutralize IL-17 have shown some promise in reducing the severity of some diseases. Conclusion: IL-17 plays a role in the pathogenesis of ocular surface and corneal disease and targeting this cytokine may provide a useful treatment option in the future.

Diagnostic tools in ocular allergy.

Ocular allergy (OA) includes a group of common and less frequent hypersensitivity disorders frequently misdiagnosed and not properly managed. The diagnosis of OA is usually based on clinical history and signs and symptoms, with the support of in vivo and in vitro tests when identification of the specific allergen is required. To date, no specific test is available for the diagnosis of the whole spectrum of the different forms of OA. The lack of recommendations on diagnosis of OA is considered a medical need not only for allergists but also for ophthalmologists. This position paper aims to provide a comprehensive overview of the currently available tools for diagnosing OA to promote a common nomenclature and procedures to be used by different specialists. Questionnaires, sign and symptom grading scales, tests, and potential biomarkers for OA are reviewed. We also identified several unmet needs in the diagnostic tools to generate interest, increase understanding, and inspire further investigations. Tools, recommendations, and algorithms for the diagnosis of OA are proposed for use by both allergists and ophthalmologists. Several unmet needs in the diagnostic tools should be further improved by specific clinical research in OA.

Conjunctival allergen provocation test : guidelines for daily practice.

Conjunctival allergen provocation test (CAPT) reproduces the events occurring by instilling an allergen on the ocular surface. This paper is the compilation of a task force focussed on practical aspects of this technique based on the analysis of 131 papers. Main mechanisms involved are reviewed. Indications are diagnosing the allergen(s)-triggering symptoms in IgE-mediated ocular allergy in seasonal, acute or perennial forms of allergic conjunctivitis, especially when the relevance of the allergen is not obvious or in polysensitized patients. Contraindications are limited to ongoing systemic severe pathology, asthma and eye diseases. CAPT should be delayed if receiving systemic steroids or antihistamines. Local treatment should be interrupted according to the half-life of each drug. Prerequisites are as follows: obtaining informed consent; evidencing of an allergen by skin prick tests and/or serum-specific IgE dosages; being able to deal with an unlikely event such as acute asthma exacerbation, urticaria or anaphylaxis, or an exacerbation of allergic conjunctivitis. Allergen extracts should be diluted locally prior to administration. Positive criteria are based on itching or quoted according to a composite score. An alternative scoring is based on itching. CAPT remains underused in daily practice, although it is a safe and simple procedure which can provide valuable clinical information.

Pegylated interferon-α-2b reduces corticosteroid requirement in patients with Behçet's disease with upregulation of circulating regulatory T cells and reduction of Th17.

OBJECTIVE: To determine whether the addition of 26 weeks of subcutaneous peginterferon-α-2b could reduce the requirement for systemic corticosteroids and conventional immunosuppressive medication in patients with Behçet's disease (BD). METHODS: We conducted a multicentre randomised trial in patients with BD requiring systemic therapy. Patients were randomised to 26 weeks of peginterferon-α-2b in addition to their standard care or to standard care only and followed 6-monthly for 3 years with BD activity scores and quality of life questionnaires. Patients at one centre had blood taken to measure regulatory T cells (Tregs) and Th17 cells. RESULTS: 72 patients were included. At months 10-12, while among the entire patient population there was no difference in the corticosteroid dose or immunosuppression use between the treatment groups (adjusted OR 1.04, 95% CI 0.34 to 3.19), post hoc analysis revealed that in patients who were on corticosteroids at baseline the corticosteroid requirement was significantly lower in the peginterferon-α-2b (6.5 (5-15) mg/day) compared with the non-interferon group (10 (8.25-16.5) mg/day, p=0.039). Furthermore, there was a trend towards an improved quality of life that became significant by 36 months (p=0.008). This was associated with a significant rise in Tregs and a decrease in Th17 cells which was still present at 1 year and 6 months after the interferon was stopped. The safety profile was similar with adverse events in 10% in both groups. CONCLUSIONS: The addition of peginterferon-α-2b to the drug regime of BD patients did not significantly reduce their corticosteroid dose required at 1 year. However, in those on corticosteroids at baseline post hoc analysis demonstrated that the addition of peginterferon-α-2b did result in a significant reduction in corticosteroid dose with a significantly improved quality of life and trend to reduce other required immunosuppressive agents. This effect was seen at 1 year and associated with a rise in Tregs suggesting a possible mode for interferon action. TRIAL REGISTRATION NUMBER: ISRCTN 36354474; EudraCT 2004-004301-18.

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.

Intracellular T lymphocyte cytokine profiles in the aqueous humour of patients with uveitis and correlation with clinical phenotype.

This study aimed to investigate whether T cells in aqueous humour are different in different types of uveitis and correlate with clinical phenotype. Patients with clinically different types of uveitis, but all displaying active anterior uveitis, were phenotyped and samples of aqueous humour (AH) and peripheral blood (PB) collected. Cells from AH and PB were separated by centrifugation and by density gradient centrifugation (to obtain mononuclear cells PBMC), respectively. Cells were activated with PMA and ionomycin in the presence of Brefeldin A, stained for surface markers and intracellular cytokines, and analysed by flow cytometry. The cytokine profile was correlated with the clinical phenotype. Increased percentages of interleukin (IL)-10+-, but not interferon (IFN)-gamma+ T lymphocytes were found in AH compared with PB in patients with acute anterior uveitis (AAU), FHC or chronic panuveitis (PU). There was a trend towards elevated levels of IL-10+ T cells in AH from patients with FHC compared with AH from acute uveitis and panuveitis patients. Increased levels of IL-10+ T cells in AH compared with PB were also found in samples from patients with isolated uveitis, but not those with associated systemic disease. Levels of cytokine-positive T cells were not associated with the use of topical steroids or to the severity of the anterior uveitis. While type I cytokine-producing T lymphocytes are present in AH during AU, the presence of increased proportions of IL-10+ T lymphocytes in AH from patients with uveitis may be indicative of an anti-inflammatory mechanism that may influence the type and course of ocular inflammation in these patients.

Antigen-specific T-cell downregulation by human dendritic cells following blockade of NF-kappaB.

Dendritic cells (DCs) are important for presenting antigen to T cells, especially naïve T cells. It has recently been shown that blocking the transcription factor, nuclear factor kappa B (NF-kappaB) in human DCs inhibited the mixed leukocyte reaction. The aim of this study was to investigate the effect of blocking NF-kappaB in DCs during presentation of antigen to memory T cells in vitro. Peripheral blood monocytes were differentiated into immature DCs with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor, and pulsed with an immunogenic tetanus toxoid peptide. Upon maturation, the antigen-pulsed DCs were highly effective in presenting antigen to autologous T cells. However, stimulation with antigen-pulsed DCs overexpressing IotakappaBetaalpha, the endogenous inhibitor of NF-kappaB, led to a significant reduction in T-cell proliferation, and decreased production of interferon-gamma, IL-4 and IL-10, whereas transforming growth factor-beta production was low throughout. There was a significant increase in apoptosis of antigen-specific T cells, even in the presence of IL-2, which was not found in resting T cells. Similar findings were observed using a proteasome inhibitor to block NF-kappaB. The effective downregulation of antigen-specific T-cell responses following blockade of NF-kappaB in DCs could be a useful approach for immunomodulating inflammatory T-cell responses.

T cells and fibroblasts in affected extraocular muscles in early and late thyroid associated ophthalmopathy.

AIM: To determine whether there are differences in the lymphocytic cell infiltrate present in affected extraocular muscles (EOM) during early and late stages of thyroid associated ophthalmopathy (TAO). METHODS: 17 biopsies of affected EOMs were collected from two groups of TAO patients (n=14): the first of five patients with early, active TAO, and the second of nine patients with late, inactive TAO. The control group was of EOM biopsies taken from 14 non-TAO patients undergoing squint surgery. Immunohistochemical analysis was undertaken using the relevant monoclonal antibodies and an avidin-biotin system and the three groups compared. RESULTS: Both CD4+ and CD8+ T cells were found in the cellular infiltrate in early, active TAO specimens which were much less evident either in late, inactive stage disease or in control tissue. There was also a significant increase in both CD45RO+ and CD45RB+ cells and macrophages in early TAO compared with the others. Increased expression of HLA-DR antigen by interstitial cells including fibroblasts was detected in both early and late disease but the EOM fibres remained morphologically intact and did not express MHC class II antigens at any time. CONCLUSION: These results demonstrate that T cells are only significantly present in early disease but increased HLA-DR antigen expression on fibroblasts is observed at all stages. This suggests that T cells are much more involved in the early than the later stages of the disease process and that early activation of fibroblasts occurs. Early intervention with immunosuppressive therapy to downregulate cytokine production by T cells may significantly influence the sequelae caused by EOM fibrosis.

Characterization of soluble factors from cultures of premalignant cervical epithelium.

PURPOSE: Immune responses within the cervical microenvironment are likely to play an important role in the natural history of premalignant lesions but the pattern of this response and how it is regulated has not been documented in detail. METHODS: Explants of premalignant cervical epithelium were cultured in vitro for 24 hours. The culture supernatants were assayed for the presence of IL-1alpha, IL-10, IL-12 and TNF-alpha by ELISA. Aliquots of each supernatant were also added to a CD3-dependent T cell proliferation assay. RESULTS: The pattern of cytokines found in different samples was heterogeneous and no significant correlation was observed between the various cytokines examined. The functional effects observed were also diverse, with some supernatants showing strong inhibitory T cell activity, while others were stimulatory. CONCLUSION: Our results document the heterogeneity of the local cytokine microenvironment of premalignant cervical lesions, which may play a role in regulating the immune response associated with such lesions and hence influence clinical outcome.

Cytokine production and mRNA expression by conjunctival T-cell lines in chronic allergic eye disease.

BACKGROUND: Activated CD4+ T cells, mast cells and eosinophils are the main cytokine-producing cell-types infiltrating the conjunctiva during chronic allergic eye diseases. Interactions between these cells are thought to play an important immunopathogenic role in these disorders (giant papillary conjunctivitis; vernal keratoconjunctivitis; atopic keratoconjunctivitis). OBJECTIVE: The objective was to compare the cytokine profiles of conjunctival T-cell lines from patients with different forms of chronic allergic eye disease. METHODS: T cells were isolated from conjunctival biopsies and non-specifically expanded into lines. The lines were immunophenotyped by flow cytometry. Cytokine production was quantified by immunoassays and more sensitive molecular techniques were used to investigate cytokine mRNA expression to identify the presence of interleukin (IL) -2, IL-4 and interferon (IFN) -gamma transcripts. RESULTS: Following four to six rounds of stimulation, the conjunctival T-cell populations were CD3+ (> 93%), with variable levels of CD4 and CD8 expression. All were HLA-DR+ (> 80%) with some HLA-DQ expression. Conjunctival T-cell lines from atopic keratoconjunctivitis produced selective increases in IFN-gamma, IL-10 and IL-13 (P<0.01), those from vernal keratoconjunctivitis produced increased IL-5 (P<0.01) whereas T-cell lines from giant papillary conjunctivitis produced only low levels of cytokines. IL-4 was only detected at the mRNA level and was expressed in four out of five T-cell lines in the vernal keratoconjunctivitis group. In contrast there was moderate to strong expression of IFN-gamma in five out of six T-cell lines in atopic keratoconjunctivitis. CONCLUSION: Different patterns of T-cell cytokine profiles were observed for each disease, with low-level, non-polarized cytokine production in giant papillary conjunctivitis, a TH2-like profile in vernal keratoconjunctivitis and a shift towards a TH1-like profile in atopic keratoconjunctivitis.

Increased CD4+ expression and decreased IL-10 in the anterior chamber in idiopathic uveitis.

PURPOSE: To compare cell types and cytokines in aqueous humor from patients with uveitis either occurring in association with a systemic disease or apparently isolated and not associated with a systemic disease. METHODS: Cells were collected by centrifugation of fresh aqueous humor from uveitis and controls, and immunofluorescence techniques were performed with markers for T cells, B cells, and monocytes. Cytokines were measured in the aqueous supernatants, and serum samples were assayed for soluble interleukin-2 receptors. RESULTS: When aqueous samples from idiopathic uveitis were compared with those from uveitis associated with a systemic disease, there were increases in CD3+, CD4+ (p = 0.001), and activated CD4+ T cells (p = 0.02) and a decrease in B cells (p = 0.0013). This was not reflected in the peripheral blood where there were no differences in the cell types or in soluble interleukin-2 receptor levels. No cells were obtainable from control aqueous. Interleukins-10 and -12, interferon-gamma, and transforming growth factor-beta2 were detected in aqueous supernatants. Interleukin-10 was reduced (p = 0.024) in uveitis in comparison with controls. CONCLUSIONS: The results suggest a selective recruitment of CD4+ T cells within aqueous humor but only in idiopathic uveitis. In both disease groups there was a decrease in the immunoregulatory cytokine interleukin-10, which might enable an immune response to occur in an otherwise highly immunosuppressive microenvironment. Increases in activated CD4+ T cells combined with depressed interleukin-10 levels could partially explain why, for example, in acute anterior uveitis, the inflammatory disease is often more severe.

Characterization of phenotype and cytokine profiles of T cell lines derived from vitreous humour in ocular inflammation in man.

Intermediate uveitis (IU) and Fuchs' heterochromic cyclitis (FHC) are two chronic ocular inflammatory disorders. They differ considerably in ocular morbidity, which is higher in IU. T cell lines were derived from the vitreous humour (VH) and peripheral blood (PB) of 10 patients with IU and four patients with FHC. There was a predominance of CD8+ in all the lines. However, there was a significantly higher percentage of CD4+ T cells in the T cell lines derived from VH of IU (32.0 +/- 8.6%) compared with FHC patients (19. 2 +/- 8.9%) (P = 0.04). The VH-derived T cell lines (VDTC) produced significantly higher levels of IL-2, interferon-gamma (IFN-gamma) and IL-10, but not IL-4, compared with PB-derived T cell lines (PBDTC) in both entities. There was significantly higher IL-2 production by VDTC from IU when compared with FHC patients (1810 +/- 220 pg/ml versus 518 +/- 94 pg/ml; P = 0.009), which could account for the more aggressive clinical features of this condition. In contrast IL-10 production was significantly higher by the VDTC from FHC compared with IU patients. The high IL-10 production by T cells infiltrating VH of FHC patients could down-regulate the inflammatory responses, thereby contributing to the benign clinical course seen in these patients. The accumulation of T cells with differing cytokine profiles in the VH suggests an important role for these cytokines in the pathogenesis of these chronic uveitides.

Lymphocyte migration through brain endothelial cell monolayers involves signaling through endothelial ICAM-1 via a rho-dependent pathway.

Lymphocyte extravasation into the brain is mediated largely by the Ig superfamily molecule ICAM-1. Several lines of evidence indicate that at the tight vascular barriers of the central nervous system (CNS), endothelial cell (EC) ICAM-1 not only acts as a docking molecule for circulating lymphocytes, but is also involved in transducing signals to the EC. In this paper, we examine the signaling pathways in brain EC following Ab ligation of endothelial ICAM-1, which mimics adhesion of lymphocytes to CNS endothelia. ICAM-1 cross-linking results in a reorganization of the endothelial actin cytoskeleton to form stress fibers and activation of the small guanosine triphosphate (GTP)-binding protein Rho. ICAM-1-stimulated tyrosine phosphorylation of the actin-associated molecule cortactin and ICAM-1-mediated, Ag/IL-2-stimulated T lymphocyte migration through EC monolayers were inhibited following pretreatment of EC with cytochalasin D. Pretreatment of EC with C3 transferase, a specific inhibitor of Rho proteins, significantly inhibited the transmonolayer migration of T lymphocytes, endothelial Rho-GTP loading, and endothelial actin reorganization, without affecting either lymphocyte adhesion to EC or cortactin phosphorylation. These data show that brain vascular EC are actively involved in facilitating T lymphocyte migration through the tight blood-brain barrier of the CNS and that this process involves ICAM-1-stimulated rearrangement of the endothelial actin cytoskeleton and functional EC Rho proteins.

The immunomodulatory effect of topical cyclosporin A in atopic keratoconjunctivitis.

PURPOSE: To perform a detailed examination of the immunomodulatory effects of topical cyclosporin A (CsA) in conjunctival tissue from patients with atopic keratoconjunctivitis (AKC). METHODS: Patients with active AKC were randomly allocated into two groups of four patients. For 3 months one group received 2% CsA drops, and the other group received placebo drops. Superior tarsal conjunctival biopsy specimens were harvested before and after treatment and examined by one- and two-color immunohistochemistry to compare leukocyte counts, HLA-DR+ and IL-2R+ cell counts, HLA-DR positivity of conjunctival epithelial cells, and counts of T cells expressing the cytokines interleukin (IL)-2, IL-3, IL-4, IL-5, and interferon (IFN)-gamma. RESULTS: Posttreatment values were significantly less than pretreatment values for the total number of leukocytes and in the numbers of CD3+ T cells, CD4+ cells, CD8+ cells, CD20+ B cells, neutrophils, and macrophages, and there was a decrease in the CD4-CD8 ratio (P = 0.03) in the CsA group. There was a reduction from before CsA treatment to after CsA-treatment in the numbers of HLA-DR+ and IL-2R+ cells (P = 0.03), but the reduction in the epithelial cell HLA-DR expression did not reach significance. The number of T cells staining for IL-3 and IL-5 was reduced, although not to statistical significance, but there was a significant reduction in the number of T cells expressing IL-2 and IFN-gamma (P = 0.03) after CsA treatment compared with initial values. There were no statistically significant differences between pretreatment and posttreatment values in the placebo group. There was a clinical improvement in the CsA group and a clinical worsening in the placebo group. CONCLUSIONS: The in vitro effects of CsA translate into a reduction in T cells, a normalization of the CD4-CD8 ratio, a decrease in T-cell activation, and a reduction in T-cell cytokine expression, especially IL-2 and IFN-gamma. The decrease in HLA-DR expression may be mediated by the change in IFN-gamma. There were fewer B cells but not fewer plasma cells after CsA and no change in IL-4 expression, suggesting minimal effects on type I hypersensitivity responses. There was no significant reduction in mast cell or eosinophil numbers, but direct effects of topical CsA on their function may play a role in the therapy of ocular allergic disease. These results show that the beneficial effects of topical CsA in AKC are accompanied by important changes in conjunctival immune cell profiles.

Eosinophil surface antigen expression and cytokine production vary in different ocular allergic diseases.

BACKGROUND: The pathophysiology of chronic ocular allergic disease is not well understood. An eosinophil infiltrate is characteristic of such disease and eosinophil activity can be related to disease severity and to keratopathy, the most serious complication. Recently, eosinophils have been shown capable of cytokine production, particularly in allergic disease, although the disease-specific cytokine spectrum of tissue eosinophils is unknown. OBJECTIVES: We sought to determine eosinophil numbers (absolute numbers and percentage of total leukocytes), cell surface antigen expression, and cytokine production in conjunctiva in chronic allergic eye disease and their relationship to corneal involvement. METHODS: Ultrathin sections of conjunctiva were examined by tissue staining and by 1- and 2-color immunohistochemistry. RESULTS: Eosinophil numbers were greater in giant papillary conjunctivitis (GPC) and vernal keratoconjunctivitis (VKC) and not related to corneal involvement. The eosinophil expression of the cell surface antigens intercellular adhesion molecule-1, CD4, IL-2R, and HLA-DR was greater in atopic keratoconjunctivitis (AKC) and VKC, the disorders with corneal disease, than in GPC, in which the cornea is not involved. For most cytokines, localization to eosinophils was greater for VKC and AKC than for GPC. RANTES, TGF-beta, and TNF-alpha localized to eosinophils in all disorders. Variations in the pattern of eosinophil-cytokine localization were found. In VKC IL-3, IL-5, IL-6, and GM-CSF were prominent; in GPC IL-5 was prominent; and in AKC IL-4, IL-8, and GM-CSF were prominent. CONCLUSIONS: Chronic ocular allergic disorders affecting the cornea are distinguished from disorders that do not do so by greater expression of eosinophil surface antigens (which may imply greater cell activation) and differences in cytokine localization to eosinophils. These differences may be secondary to the variations in T-cell subsets or a primary phenomenon. Changes in eosinophil function, rather than cell numbers, may be important in clinical variations, such as keratopathy, and may allow future therapeutic exploitation.

A randomized, placebo-controlled trial of topical cyclosporin A in steroid-dependent atopic keratoconjunctivitis.

OBJECTIVE: This study aimed to investigate the therapeutic effect of topical cyclosporin A (CsA) 2% in maize oil as a steroid-sparing agent in steroid-dependent atopic keratoconjunctivitis. DESIGN: Prospective, randomized, double-masked, placebo-controlled trial. PARTICIPANTS: Twenty-one patients with steroid-dependent atopic keratoconjunctivitis were studied. INTERVENTION: Patients used either topical CsA or vehicle four times daily for 3 months in addition to their usual therapy, and the clinical response was used to taper or stop topical steroids when possible. MAIN OUTCOME MEASURES: Steroid drop usage per week, ability to cease steroid use, scores for symptoms and clinical signs, drop side effects, and overall subjective rating of trial drop by patients and clinician were measured. RESULTS: Cyclosporin A had a greater steroid-sparing effect than did placebo. Nine of 12 CsA patients ceased steroids compared to 1 of 9 placebo patients (P = 0.01), the final steroid use was lower in the CsA group (2.6 +/- 1.4 vs. 27.7 +/- 17.7, P = 0.005), and the mean reduction in steroid use was greater for CsA (85.5 +/- 14.7 vs. 13.9 +/- 16.0, P = 0.005). Clinical signs and symptom scores were reduced to a greater level for CsA. Serious side effects were lid skin maceration in one patient using CsA and an allergic reaction in one placebo patient. Marked blurring of vision after drop instillation was common in both groups, but intense stinging was more common in CsA patients (9/12 vs. 1/9, P = 0.01), limiting frequency of drop use. The clinician rated the trial drops as good or excellent more frequently for CsA (11/12 vs. 0/9, P < 0.0001). CONCLUSIONS: Topical CsA is an effective and safe steroid-sparing agent in atopic keratoconjunctivitis and, despite difficulties in patient tolerance, also improves symptoms and signs.

Characterization of T cells and cytokines in the aqueous humour (AH) in patients with Fuchs' heterochromic cyclitis (FHC) and idiopathic anterior uveitis (IAU).

FHC and IAU are two forms of anterior uveitis which are localized to the eyes with no evidence of systemic involvement. However, FHC has distinct clinical features and differs from IAU in that the inflammation is low grade, steroid non-responsive, and has a less aggressive clinical course. To try to dissect the mechanism for this difference the phenotypes of the cells in the AH and blood (PB) and the cytokines present in the AH in patients with FHC and IAU were compared. Three-colour flow cytometry was performed on the cells isolated from the AH and PB. Percentage of cells bearing the following markers were determined: CD3, CD4, CD8, CD4/CD25, CD8/CD25, CD19 and CD14. The cytokines IL-4, IL-10, IL-12 and interferon-gamma (IFN-gamma) were assayed by ELISA. In both groups T cell numbers were higher in the AH than PB, although the distribution of T cell subsets in PB was similar. In the AH, CD8+ T cell numbers were higher in FHC than in IAU (P = 0.003), whilst CD4+ numbers were higher in IAU than FHC (P = 0.01). AH cytokine profiles were different in the two groups: IFN-gamma levels were higher and IL-12 levels lower in the FHC group than IAU (P = 0.02), whilst IL-10 levels tended to be higher in the FHC group (P = 0.5). We suggest that different local mechanisms governing the balance of T cell/cytokine-mediated inflammation in the anterior segment may underlie clinical differences such as chronicity and response to steroids in these disorders.

The role of conjunctival epithelial cells in chronic ocular allergic disease.

Recent evidence suggests that mucosal epithelial cells are capable of actively participating in immune reactions via expression of surface antigens, such as adhesion molecules, and synthesis of cytokines. This appears to be important in the pathophysiology of non-ocular allergic disorders. The objectives of the experiments were to compare the expression of HLA-DR, ICAM-I and pro-allergic cytokines in conjunctival epithelial cells in the different chronic ocular allergic disorders with each other and with normal subjects. Conjunctiva from normal patients (n=10) and patients with vernal keratoconjunctivitis (VKC, n=10), atopic keratoconjunctivitis (AKC, n=10) and contact lens-associated giant papillary conjunctivitis (GPC, n=10) were examined by immunohistochemistry. Epithelial cell staining for surface antigens and cytokines was graded by one masked observer using a four point scale based on the percentage of epithelial cells staining positive. There was no expression of ICAM-1 or HLA-DR in the normal conjunctival epithelial cells, but both antigens were induced on conjunctival epithelial cells in the allergic tissue, and there was greater expression in AKC and VKC compared with GPC. Cytokines IL-6, IL-8, RANTES and TNF-alphaall localised to normal conjunctival epithelial cells. RANTES was upregulated in all the allergic disorders and IL-8 was upregulated in GPC. IL-3 and GM-CSF were not expressed in normal conjunctival epithelial cells. GM-CSF was expressed in all disorders and there was greater expression in AKC compared with GPC and VKC. IL-3 was expressed only in AKC and VKC epithelial cells. These results suggest that conjunctival epithelial cells play an important pro-inflammatory role in chronic ocular allergic diseases; ICAM-1 may allow epithelial cells to recruit, retain and locally concentrate leukocytes; the presence of HLA-DR raises the question of conjunctival epithelial cell antigen presentation. The epithelial cytokines which are upregulated are known to promote eosinophilic inflammation and are typical of allergic inflammation. The differences in cytokine patterns may be exploitable for future therapy.

Analysis of extraocular muscle-infiltrating T cells in thyroid-associated ophthalmopathy (TAO).

TAO is characterized by an autoimmune process affecting the orbital contents. T cells have been suggested to have a major role in pathogenesis, but so far only limited data are available to clarify the extraocular muscle (EOM)-infiltrating T cell phenotype, antigenic reactivity and cytokine profile in TAO patients. In the present study, biopsies of affected EOM were taken and the infiltrating T cells isolated and expanded in vitro with mitogen. Their phenotype was determined by flow cytometric (FACS) analysis and compared with peripheral blood-derived T cell lines, treated in the same way from the same patient. Cytokines present in the supernatant after mitogen stimulation of the T cell lines were assayed by ELISA. In addition, cytokine mRNA present at the time of biopsy was determined by rapid RNA extraction from EOM and reverse transcription-amplification with specific cytokine oligonucleotide probes (IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, IL- 15, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha)). In the T cell lines from two patients, proliferation assays were carried out with antigens derived from thyroid gland, EOM and a thyrotropin (TSH) receptor preparation. Most T cell lines were CD4+, CD45RO+, and TCR alpha/beta+, both from the EOM and the peripheral blood. A wide variety of cytokines was detected by analysis of supernatants or mRNA, but the profiles were not identical comparing the two approaches. However, IL-4 was detected by both. Dose-dependent proliferation was observed in response to thyroid extract in a biopsy-derived T cell line. In conclusion, EOM-infiltrating T cells from patients with TAO, expanded in vitro, were chiefly CD4+ and produced a mixture of cytokines, including IL-4. The proliferation data suggest that there are thyroid-reactive T cells in EOM.