[Cystoid macular edema in uveitis]. / Zystoides Makulaödem bei Uveitis.

Cystoid macular edema (CME) is the most frequent cause of visual deterioration in uveitis patients. Intraocular inflammation disturbs the blood-retina barrier and leads to retinal edema. The basis of successful treatment is the anti-inflammatory and immunosuppressive therapy of uveitis. Restoration of the blood-retina barrier is mediated by corticosteroids and nonsteroidal anti-inflammatory agents. Resorption of extracellular fluid is improved by systemic carboanhydrase inhibitors. Despite aggressive therapy loss of visual acuity is frequent. Therefore, early diagnosis of CME and initiation of treatment, even if visual acuity is not yet impeded, is mandatory.

Immune responses to retinal autoantigens and peptides in equine recurrent uveitis.

PURPOSE: To test the hypothesis that autoimmune mechanisms are involved in horses in which equine recurrent uveitis (ERU) develops spontaneously. METHODS: Material obtained from horses treated for spontaneous disease by therapeutic routine vitrectomy was analyzed for total IgG content and IgG specific for S-Antigen (S-Ag) and interphotoreceptor retinoid-binding protein (IRBP). The cellular infiltrate of the vitreous was analyzed by differential counts of cytospin preparations and flow cytometry using equine lymphocyte-specific antibodies. Antigen-specific proliferation assays were performed comparing peripheral blood lymphocytes (PBLs) with vitreal lymphocytes by stimulation with S-Ag and several S-Ag- and IRBP-derived peptides. RESULTS: The total IgG content of specimens from horses with ERU was very high with great variability among the investigated samples (11.5 +/- 8.0 mg). Autoantibodies to S-Ag or IRBP or both were found in 72% of vitreous specimens from horses with uveitis. The leukocyte infiltrates (up to 2 x 10(8) cells per sample) were dominated by lymphocytes (>90%) in most cases (22/32). Flow cytometry showed that more than 50% of these cells were CD4(+) T cells. In vitro stimulation of vitreal lymphocytes, but not of PBL, showed a strong proliferative response to peptides derived from S-Ag or IRBP in 9 of 12 patients. CONCLUSIONS: In the eyes of horses with ERU, IgG antibodies and autoreactive T cells specific for retinal antigens were detected. These results strongly support the hypothesis that ERU is an autoimmune-mediated disease and is highly similar to recurrent uveitis in humans in both clinical and immunologic parameters.

Ocular inflammation stimulated by intravitreal interleukin-8 and interleukin-1.

Interleukin-8 (IL-8), a cytokine with neutrophil chemotactic and activating properties, is known to be stimulated by IL-1. Fischer rats are more resistant to inflammation than Lewis rats probably due to a higher corticosteroid stress response. To determine the role of IL-8 in ocular inflammation, the effect of intravitreal injection of IL-8 was compared with that of IL-1 in both Lewis and Fischer rats. The IL-8, IL-1 alpha, or sterile balanced salt solution (control) was injected into one eye of each animal. Both IL-8 and IL-1 alpha caused inflammation in the eye of both strains, as detected by leukocyte counts of the anterior chamber and histopathologic examination. The eyes of animals injected with a cytokine had significantly higher numbers of leukocytes compared with eyes of control animals. Histopathologic examination confirmed these findings. The IL-1 alpha induced inflammation more consistently and more severely than the most effective dose of IL-8. This finding agreed with the concept of IL-1 initiating a cascade of inflammatory mediators including IL-8, which acts more specifically on a smaller population of leukocytes. A contralateral response was observed in the uninjected eye of experimental and control animals. The contralateral response in animals receiving the cytokines was significantly greater than that in controls. Lewis rats show a higher inflammatory response to the injections than do the Fischer rats. These data suggest that IL-8 may be active as one component in neutrophil-mediated ocular inflammation.

Molecular mimicry as a therapeutic approach for an autoimmune disease: oral treatment of uveitis-patients with an MHC-peptide crossreactive with autoantigen--first results.

In the rat model of experimental autoimmune uveitis (EAU) we have demonstrated that a peptide from the sequence of human disease-associated MHC-class I antigens can induce uveitis upon immunization. Moreover, oral administration of this MHC-peptide tolerized Lewis rats to the disease induced with two different retinal autoantigens, retinal S-antigen (S-Ag) and IRBP. In uveitis patients T cells responding to S-Ag peptide also respond to the MHC-peptide, which shows crossreactivity with the major epitope from S-Ag due to some shared discontinuous amino acid homologies. The 14-mer peptide B27PD is derived from the sequence of all HLA-B antigens that are statistically associated with uveitis (including HLA-B27). Patients with long-lasting endogenous uveitis, suffering from side effects of conventional immuno-suppressive therapy or being therapy-refractive, were orally tolerized with peptide B27PD in this first open therapeutic trial. Patients received peptide three times a week over a 12 weeks period, while only low dose steroids were allowed as concomitant medication. The aims were (1) to investigate whether immunosuppressive therapy could be discontinued and steroids reduced while relapses of ocular inflammation reside and (2) to search for side effects. The Helsinki Declaration was strictly observed and the study design approved by the local ethical committee. The first patients orally tolerized with the HLA-peptide (two had stopped azathioprine immediately prior to onset of oral peptide treatment) could discontinue their steroids because of reduced intraocular inflammation. No side effects of therapy were observed. Oral tolerance induction with a peptide derived from the patients' own HLA-antigens and crossreactive with the organ-specific autoantigen seems to be a potent therapeutic approach.

Oral tolerance with an HLA-peptide mimicking retinal autoantigen as a treatment of autoimmune uveitis.

Endogenous uveitis is a T cell mediated autoimmune disease leading to impairment of visual acuity. The association of different uveitis entities with HLA-class I antigens and the discovery of antigenic mimicry between a peptide of uveitis-associated HLA-class I antigens and a peptide of retinal autoantigen led to a new hypothesis for the pathogenesis of uveitis. On the basis of this mechanism an open trial of oral tolerance induction with the HLA-peptide B27PD was initiated for nine patients with long lasting, therapy-refractive uveitis. Within 6 weeks of oral peptide treatment all patients responded with a marked decrease of intraocular inflammation, which allowed a reduction of systemic corticosteroids in seven patients. One patient, who suffered from an acute relapse, responded within 2 weeks, followed by an increase of visual acuity. In addition, two patients discontinued azathioprine immediately prior to oral tolerance induction without the occurrence of relapses. Visual acuity remained unchanged or increased in 14 of 16 eyes. One patient did not finish oral peptide treatment. None of these patients experienced any adverse events. It was concluded that the oral application of highly tolerogenic peptides might be a potent approach for the treatment of autoimmune diseases.

Trials of vaccination against experimental autoimmune uveoretinitis with a T-cell receptor peptide.

T lymphocytes which mediate several experimental autoimmune diseases, including encephalomyelitis (EAE) and uveoretinitis (EAU) in Lewis rats, preferentially utilize V beta 8 gene product in their receptor. Vaccination against a V beta 8.2-derived peptide was reported to inhibit EAE induction and we report here on the effect of vaccination with this peptide on the development of EAU. Experimental rats were pretreated with the V beta 8.2 peptide, emulsified in adjuvant (CFA), whereas control animals were untreated or injected with saline in CFA. Rats of all groups were immunized 30 or 40 days later with the immunopathogenic antigen, emulsified in Mycobacterium-enriched CFA. Vaccination with CFA emulsions containing either the V beta 8.2 peptide or saline, remarkably inhibited the development of the tested diseases, as compared to the untreated controls. Vaccination with the V beta 8.2 peptide had variable effects in this study on disease development: it inhibited the S-antigen-induced EAU more than did treatment with CFA in four out of six experiments, had a similar effect to that of CFA in one experiment and enhanced the disease in another experiment. Conversely, vaccination with the V beta 8.2 peptide slightly enhanced the EAU induced by the interphotoreceptor retinoid-binding protein (IRBP), or its dominant determinant, in three of four experiments and had no apparent effect in the fourth experiment. In addition, we could not reproduce the reported protective effect of vaccination with the V beta 8.2 peptide against induction of EAE. Vaccination with the V beta 8.2 peptide also had no clear effect on the development of humoral or cellular immune responses against S-antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Endotoxin-induced production of inflammatory mediators by cultured ciliary epithelial cells.

Systemic injection of bacterial endotoxin (Lipopolysaccharide, LPS) in experimental animals induces anterior uveitis without major pathological changes in other organs. The present study investigates the effect of LPS on production of inflammatory mediators in cultured bovine pigmented ciliary epithelial cells (CB-cells) by means of radioimmunoassays and bioassays. LPS was found to stimulate CB-cells to secrete prostaglandin E2 and prostacyclin (assayed as its stable metabolite 6-keto-prostaglandin F1a), but not leukotriene B4 or thromboxane A2 (assayed as its stable metabolite thromboxane B2). CB-cells produced membrane-associated interleukin 1-activity in response to LPS, but no tumor necrosis factor-activity was found after challenge of CB-cells with LPS. The direct effect of LPS on production of inflammatory mediators by cells from the anterior uvea could play a role in the pathophysiology of endotoxin-induced uveitis.

[Does combined pancreas-kidney transplantation modify diabetic retinopathy in type-1 diabetic patients?]. / Beeinflusst die kombinierte Pankreas-Nieren-Transplantation die diabetische Retinopathie bei Typ-1-Diabetikern?

The study group consisted of 30 patients with a functioning pancreas graft of at least 12 months. Fifty-seven eyes were examined; 26 eyes from 15 patients with a non-functioning pancreas graft made up the control group. Three patients were in both groups because their graft was rejected after a 12-month period. The mean age in the study group was 37 years, the mean observation time 38 months. The mean duration of diabetes before transplantation was 24 years and all patients were on kidney dialysis. Retinal coagulation for diabetic retinopathy had previously been performed in 80.7% of the patients. The mean age (38 years), observation time (36 months), duration of diabetes before transplantation (24 years), and incidence of retinal coagulation (84.6%) were comparable in the control group. All patients had regular ophthalmological examinations every 6 to 12 months. This included best-corrected visual acuity, applanation tonometry, slit-lamp examination and dilated binocular funduscopy. Seven 30 degrees fundus pictures of the posterior pole were taken: The images were graded by comparing them with the ETDRS (Early Treatment Diabetic Retinopathy Study) Group standard photographs. The original Airlie House grading scale was changed because we did not take stereoscopic pictures. Evaluation and grading were done independently by two examiners. The retinopathy score was graded from 0 (no retinopathy) to 11 (no evaluation possible due to opaque media). Visual acuity remained stable in both the study and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Recurrent uveitis of unknown origin in childhood]. / Kindliche rezidivierende Uveitis unklarer Genese.

This report describes a 12-year-old girl with diffuse infiltrating retinoblastoma. This inflammatory condition belongs to the uveitis masquerade syndromes, which comprise a group of various ocular diseases such as chronic intraocular inflammation and ocular tumors.

[Topical and systemic corticosteroid therapy for uveitis in childhood]. / Topische und systemische Kortikosteroidtherapie bei Uveitis im Kindesalter.

Systemic and topical corticosteroids constitute an important part in the treatment of children with uveitis, because of their rapid therapeutic onset. Patients with anterior uveitis receive eye drops initially every 30 minutes or every hour. Children will experience the same side effects as adults but, in addition, there will be a growth retardation. Therefore, if treatment is required for extended periods of time it is important to avoid steroid quantities above the Cushing level and to initiate an additional systemic immunosuppressive treatment regimen early.

Orally induced bystander suppression in experimental autoimmune uveoretinitis occurs only in the periphery and not in the eye.

Oral administration of retinal soluble antigen (S-Ag) suppresses the induction of S-Ag-mediated experimental autoimmune uveitis (EAU) in Lewis rats. EAU induced with interphotoreceptor retinoid-binding protein (IRBP), another retinal autoantigen, can also be suppressed by oral administration of IRBP. It has been speculated that feeding with one retinal autoantigen could suppress induction of uveitis with the other retinal protein by means of bystander suppression. Both uveitogenic effector and suppressor cells should find their antigens within the retina, where the suppressor cells would be expected to act on the effector cells. However, reciprocal combinations of antigens used for induction and suppression of uveitis failed to prevent onset of disease, demonstrating that bystander suppression obviously does not occur in the eye. To investigate further the localization of suppressor mechanisms, we fed Lewis rats either with retinal S-Ag or with ovalbumin (OVA) and then immunized the animals either with a mixture of S-Ag and OVA or with each antigen separately, injected into contralateral hind legs. Feeding of S-Ag prior to immunization led to suppression of uveitis, whereas feeding of OVA had no tolerizing effect when S-Ag and OVA were injected into different legs. Nevertheless, immunizing rats with a mixture of S-Ag and OVA after OVA feeding suppressed uveitis to a high degree. These findings suggest that orally induced bystander suppression might not occur in the target organ, but rather peripherally at the site of induction of the autoimmune T cells.

Cross-reactivity between an HLA-B27-derived peptide and a retinal autoantigen peptide: a clue to major histocompatibility complex association with autoimmune disease.

Statistical correlations between the expression of various HLA antigens and certain autoimmune diseases have been observed for both HLA class I and II antigens. Autoimmune diseases like spondyloarthropathies and anterior uveitis are associated with HLA-B27, but uveitis in Behçet's disease with HLA-B51. We describe a peptide from disease-associated HLA class I antigens sharing sequence homologies with a highly uveitogenic epitope from the retinal autoantigen S-antigen. S-antigen induces autoimmune uveitis in the animal model and is a major autoantigen in human disease. The HLA peptide induced uveitis in the Lewis rat and, moreover, suppressed S-antigen-induced disease when administered orally. Patients' PBL cross-reacted with the HLA- and corresponding retinal peptide, explaining the organ specificity of the disease.

Orally induced, peptide-specific gamma/delta TCR+ cells suppress experimental autoimmune uveitis.

We investigated the role of gamma/delta TCR+ T cells in induction and suppression of the T cell-mediated disease experimental autoimmune uveitis. Disease induction was studied in Lewis rats perinatally depleted of alpha/beta or gamma/delta TCR+ subpopulations. Depletion of alpha/beta TCR+ cells completely abrogated disease, whereas treatment with anti-gamma/delta antibodies had no influence on onset or intensity of uveitis. However, adoptively transferred gamma/delta+ cells from orally tolerized rats could mediate suppression of uveitis in an antigen-specific fashion. Uveitis induced by a peptide derived from the uveitogenic retinal soluble antigen (S-Ag) was suppressed by gamma/delta+ cells from rats orally tolerized with the same peptide as well as HLA peptide B27PD. This disease ameliorating effect could also be observed when rats were fed with the HLA peptide before immunization with S-Ag peptide. Transfer of alpha/beta+ T cells from the same donors as well as gamma/delta+ or alpha/beta+ cells from animals fed with control peptide had no ameliorating effect.

Expression and immunogenicity of HLA-B27 in high-transfection recipient P815: a new method to induce monoclonal antibodies directed against HLA-B27.

The immunization of a (BALB/c x C57BL/6) FI mouse with murine transfectants expressing the HLA-B27 antigen resulted in a panel of polymorphic monoclonal antibodies with specificity for HLA-B27 and some additional HLA-antigens. Specificity of the antibodies was defined by cytofluorometric analysis on a panel of lymphoblastoid cell lines (LCL) derived from HLA typed individuals. Three of these antibodies are cytotoxic, and one of them inhibits B27-specific T cell cytotoxicity. Our results indicate that HLA-class I transfectants could be used to generate polymorphic antibodies, and that these antibodies may be helpful for HLA typing and for definition of epitopes recognized by T cells.

Oral tolerance in a murine model of relapsing experimental autoimmune uveoretinitis (EAU): induction of protective tolerance in primed animals.

Oral administration of uveitogenic retinal antigens suppresses the expression of EAU induced by a subsequent immunization with these antigens. Effectiveness and mechanisms of oral tolerance in EAU have mainly been studied in the acute, monophasic model in Lewis rats by feeding antigen prior to induction of disease. In this study we investigated the effect of oral tolerance induction in the acute as well as the chronic-relapsing models in the B10.A mouse. In acute murine EAU we could effectively suppress disease by induction of oral tolerance prior to immunization. In the chronic-relapsing EAU, antigen feeding was started only after the animals had recovered from their first attack of uveitis. Under these experimental conditions the subsequent relapse was largely prevented. These experiments demonstrate that oral tolerance may have practical clinical implications in uveitis, which is predominantly a chronic-relapsing condition in humans.

Lymphocytes, macrophages and HLA-DR expression in vitreal and epiretinal membranes of proliferative vitreoretinopathy. An immunohistochemical study.

Proliferative vitreoretinopathy (PVR) as a severe complication of retinal detachment and also the main cause of failure in its treatments is not yet completely understood. In the present study, we examined 16 PVR epiretinal membrane specimens removed during vitrectomy from 16 patients with complicated rhegmatogenous retinal detachment by immunostaining of cryosections. We looked for the presence of lymphocytes and detected helper/inducer T lymphocytes (CD4+), suppressor/cytotoxic T lymphocytes (CD8+), B lymphocytes (CD22+), macrophages (CD68+), and HLA-DR expression. The results showed that 6 out of 16 specimens reacted positively with monoclonal antibody against the helper/inducer T cell subset (38%), 5 out of 16 reacted positively with a suppressor/cytotoxic T cell-specific monoclonal antibody (31%), 7 out of 16 reacted with B cell-specific monoclonal antibody (44%), and 14 out of 16 were positive for macrophages and HLA-DR (88%). Nevertheless, we think that the invasion of macrophages and lymphocytes into the membranes is not the cause for the pathogenesis, but a secondary event that might further complicate the course of the disease.

[Active immune regulation by cells of the ciliary body]. / Aktive Immunoregulation durch Zellen des Ziliarkörpers.

Immunoregulation in the eye requires both an effective defense against exogenous pathogens and protection of the delicate anatomy of the eye against "innocent bystander destruction", which accompanies inflammatory reactions. We studied the role of uveal cells for local immunoregulation in the eye and investigated the effect of cultured Lewis rat ciliary body cells on antigen-specific 3[H]-thymidin incorporation in a T-helper-lymphocyte cell line (ThS) specific for the retinal-soluble antigen (SAg). Ciliary body cells inhibit the proliferation of ThS. This inhibition is not species-specific and is mediated by at least two mechanisms: a soluble inhibitor and a contact-requiring factor that is trypsin-sensitive, suggesting a protein molecule. After removal of these inhibitory components, ciliary body cells also exhibit the capacity to effectively present SAg to ThS. This dual effect of ciliary body cells on T-helper lymphocytes supports the concept of active local immunoregulation in the eye.