Dexamethasone implants in paediatric patients with noninfectious intermediate or posterior uveitis: first prospective exploratory case series

BACKGROUND

To evaluate the efficacy and safety of dexamethasone (DEX) implants in paediatric patients with noninfectious intermediate or posterior uveitis.

METHODS

Prospective single center exploratory case series. Children and adolescents, 6 to 17 years old, with a vitreous haze score of ≥1.5+ or cystoid macular edema (CME) of >300 μm were enrolled. Vitreous haze score at month 2 was chosen as primary endpoint. Best corrected visual acuity (BCVA), central retinal thickness (CRT) and concomitant medication at month 6 were defined as secondary endpoints. Intraocular pressure (IOP) and cataract formation were determined as safety endpoints.

RESULTS

Three out of 6 eligible patients participated in the case series. At month 2, vitreous haze was reduced from a score of 1.5+ to 0.5+ and 0 and BCVA improved by ≥3 lines, ≥4 lines and ≥2 lines of Early Treatment of Diabetic Retinopathy (ETDRS)-letters, respectively. Visual acuity gain was accompanied by a CRT reduction of -186 μm and -83 μm in the first and third patient, in whom CME was the indication for DEX implantation. A reduction of concomitant medication was achieved in 1 patient. IOP increase was seen in all 3 patients, but could be treated sufficiently with primarily IOP lowering medications and without need for glaucoma surgery. Cataract progression did not occur.

CONCLUSIONS

DEX implants led to an improvement in all endpoints, especially BCVA. This study confirms that IOP rises may also occur in the paediatric population and should be monitored and treated appropriately.

TRIAL REGISTRATION

European Union Drug Regulating Authorities Clinical Trials (EudraCT)- nr: 2013-000541-39.

Development and evaluation of dexamethasone nanomicelles with potential for treating posterior uveitis after topical application

PURPOSE

This study aims at the development and preliminary evaluation of dexamethasone nanomicelles for treating posterior uveitis. Nanomicelles were formulated using polyoxyl 40 stearate (P40S) and polysorbate 80 (P80), which are approved by the FDA for ocular use.

METHODS

Dexamethasone nanomicelles were prepared and characterized for critical micellar concentration, solubility of dexamethasone, particle size, surface charge, morphology, in vitro drug release, clarity, stability, filtration efficiency, and sterility. Ocular tolerance and the tissue drug distribution of dexamethasone were assessed in rabbits after single and multiple topical administration.

RESULTS

Dexamethasone nanomicelles (0.1% w/v) were successfully developed and characterized with an optimized composition of P40S/P80=7/3 by weight. The mean diameter of blank and drug-loaded nanomicelles was 13.3±0.4 and 14.5±0.4 nm, respectively. Transmission electron microscopy images revealed the spherical structure of nanomicelles. Nanomicelles were found to be stable with respect to clarity, size and drug content at 4°C and 25°C for up to 6 months. No irritation or redness was observed in the treated eyes as compared with the untreated control rabbit eyes. Therapeutic concentrations of dexamethasone were observed in the retina and choroid after single and multiple topical application in rabbits.

CONCLUSION

In conclusion, the nanomicelles of P40S and P80 could efficiently solubilize 0.1% dexamethasone in their cores. The results also indicate that mixed nanomicelles could be utilized as a potential delivery system for delivering dexamethasone to treat the back of the eye diseases such as posterior uveitis after topical application.

[Intravitreal ranibizumab in the treatment of subretinal neovascularization in a case of punctate inner choroidopathy]

CASE REPORT

We report the case of a 28-year old woman suffering loss of visual acuity in her left eye, who presented an image suggestive of a subretinal neovascular membrane in her left eye, and bilateral retinal lesions compatible with punctate inner choroidopathy (PIC). She was treated with intravitreal ranibizumab obtaining excellent results.

DISCUSSION

The differential diagnosis must be made between PIC and the rest of "white dot syndromes" and the presumed ocular histoplasmosis syndrome (POHS). Antiangiogenic drugs may be a good alternative for the treatment of such diseases when they develop a subretinal neovascular membrane.

Analysis of Immune Privilege in Eyes withMycobacteria tuberculosaAdjuvant-Induced Uveitis

PURPOSE

To examine the effects of intravitreal Mycobacteria tuberculosa adjuvant (MTA) on ocular immune privilege.

METHODS

MTA was injected into the vitreous cavity of BALB/c mouse eyes to induce anterior uveitis. The inflamed eyes were then examined for their capacity to afford immune privilege to injected allogeneic tumor cells and to promote anterior chamber-associated immune deviation (ACAID). Aqueous humor (AqH) was tested for IL-12 content and for its ability to inhibit T-cell activation.

RESULTS

AqH removed from MTA-inflamed eyes at 6 and 12 h contained high levels of IL-12, which then fell almost to baseline at 24 h. This is relevant to the finding that the inflamed eye failed to support ACAID induction at an early time period and then regained the ACAID-induction capability at a later time. Nonetheless, AqH removed from MTA-inflamed eyes retained its capacity to suppress T-cell activation, and MTA-inflamed eyes afforded extended survival to alloantigenic tumor cells implanted into the anterior chamber.

CONCLUSION

Intraocular inflammation evoked by MTA causes the local accumulation of IL-12 and simultaneously robs the eye of its capacity to promote systemic immune tolerance to eye-derived antigens. However, MTA-inflamed eyes retain immune privilege, as indicated by their support of the progressive growth of allogeneic tumor cells.

Immunopathology and altered immunity in posterior uveitis in man: a review

Posterior uveitis is thought to be a T-cell mediated disease since active foci of inflammation, identified in eyes enucleated for the complications of intraocular inflammation, are found to be predominantly composed of CD4+ T-cells. Few B-cells and little immunoglobulin are found suggesting that antibody and immune complex deposition do not play a major role in perpetuating the inflammatory process. As ocular biopsy is not a feasible method for monitoring disease activity and response to treatment, parameters of T-cell activation and retinal damage have been studied in the peripheral blood. These have included antibody and T-cell sensitisation to retinal S-antigen, serum soluble IL-2 receptors and IL-2 receptors on activated T-cells. none of these parameters, however, have been found to be useful in the monitoring of ocular disease activity alone or in the prediction of disease relapse.

Identification of novel dendritic cell populations in normal mouse retina

PURPOSE

Whether tissue resident or infiltrating antigen-presenting cells (APCs) are involved in modulating immune responses in the retina and initiating inflammation is controversial. In this histologic study, the authors examine the retinas of mice strains with different susceptibility to experimental autoimmune uveoretinitis (EAU) for tissue resident APC.

METHODS

Retinal wholemounts from normal and inflamed eyes of B10R III, C57BL/6, BALB/c, and ABH Biozii mice were immunostained for APC markers (33D1, CD11c, CD11b, major histocompatibility complex [MHC] class II, F4/80, CD80, CD86, CD205, mPDCA, B220, and GR1) and analyzed by confocal fluorescence microscopy using emission fingerprinting and three-dimensional reconstruction techniques. Hematoxylin and eosin-stained histologic sections were used to evaluate EAU disease scores and to assess outer blood retina barrier (retinal pigment epithelium [RPE]) structures.

RESULTS

A population of 33D1(+) cells was identified exclusively in the peripheral margins and juxtapapillary areas of the retina in normal, nonimmunized C57BL/6 adult mice. These cells were also MHC class II(high), and their location corresponded to sites of earliest inflammation in EAU. Numbers in the papillary area were very low (less than 10), but this region marked the predominant anatomic site for initiation of inflammation in this moderately susceptible strain. The distribution and phenotype of these cells within the retinas differed between mouse strains exhibiting different disease susceptibility. In EAU-resistant BALB/c mice, many more 33D1(+) dendritic cells were present in the normal retina but were MHC class II(low/-). Conversely, no 33D1(+) or MHC class II (+) dendriform cells could be found in the normal retinas of highly EAU-susceptible B10.RIII mice.

CONCLUSIONS

A novel population of 33D1(+) DCs was identified in normal mouse retina. The function of these cells remains to be defined, but increased numbers correlate positively with structural abnormalities in the RPE and increased resistance of the strain to EAU.

Topographic optic disc analysis by Heidelberg retinal tomography in ocular Behcet's disease

AIM

To compare the topographic characteristics of the optic discs in patients with severe and mild ocular Behçet's disease by using Heidelberg retinal tomographaphy (HRT).

METHODS

This prospective study included 47 eyes of 47 patients with ocular BD who were being followed-up at the Uveitis Clinic of the Ankara Ulucanlar Eye Research Hospital, Ankara, Turkey. The patients were divided into two groups. Group 1 consisted of 21 eyes with mild uveitis, and group 2 consisted of 26 eyes with severe uveitis. All patients underwent topographic optic disc analysis by HRT II, and the quantitative optic disc parameters of both groups were compared by non-parametric Mann-Whitney U test.

RESULTS

The mean cup volume, rim volume, cup area, disc area and cup depth in group 1 were found to be statistically significantly greater than those in group 2 (p<0.0001, p = 0.03, p = 0.021, p = 0.01 and p = 0.017, respectively), while the difference between the mean cup-to-disc ratios in group 1 and group 2 were found to be statistically insignificant (p = 0.148).

CONCLUSION

A relationship was found between the severity of ocular BD and optic disc topography determined by HRT. In eyes with smaller optic discs, uveitis was observed to have a more severe course with more frequent relapses than those with larger discs.

Ocular complications of childhood rheumatic diseases: uveitis

Ocular involvement is common in pediatric rheumatologic diseases, supporting the concept that these conditions cannot be understood simply as isolated entities, but rather as multisystem disorders. The reasons for the breach of the eye-brain barrier and the targeting of the usually well-shielded eye during a pan-inflammatory process remains unclear. Pediatric rheumatologists should become familiar with these ocular disorders, because as important members of the treatment team, they manage more serious cases of inflammatory eye disease. A close collaboration between the treating rheumatologist and the ophthalmologist is essential to prevent potentially devastating outcomes. Therapeutic interventions such as topical steroids, systemic immunosuppressants, and biologics must balance the necessity of controlling ocular inflammation and the adverse effects of these treatments on a growing child.

Osteopontin Is Proinflammatory in Experimental Autoimmune Uveitis

PURPOSE

Osteopontin (OPN) has been implicated in inflammatory and wound-healing processes. Increased OPN mRNA levels have been reported in experimental autoimmune uveitis (EAU), but the function of OPN in the inflamed eye is unknown. The purpose of this study was to investigate the role of OPN in the pathogenesis of EAU.

METHODS

EAU was induced in OPN-null and wild-type (WT) mice by immunization with interphotoreceptor retinoid-binding protein (IRBP). Immunofluorescence experiments were performed to identify OPN-positive cells in WT mice. Disease incidence, serum IRBP antibody levels, vitreous infiltrates, retinal granulomas, and lymphocyte proliferation were assessed in OPN-null and WT mice. To determine whether OPN could induce an EAU-like condition, purified OPN and OPN fragments were injected intraocularly into WT mice and vitreous infiltrates were characterized and quantified.

RESULTS

In WT EAU-positive eyes, cell types with increased OPN immunoreactivity were identified as F4/80-positive macrophages/microglia and CD4-positive T cells. OPN-null mice manifested attenuated disease with decreased vitreous infiltrates, fewer granulomas, less lymphocyte proliferation, and lower serum IRBP antibody levels. Exogenous full-length OPN, as well as N- and C-terminal fragments, induced leukocyte infiltration and retinal folding, with some similarities to EAU.

CONCLUSIONS

The results demonstrate that OPN is proinflammatory in EAU and may be important for recruitment and activation of leukocytes in retinal inflammation.

Triamcinolone-induced intraocular pressure elevation: intravitreal injection for macular edema and posterior subtenon injection for uveitis

Purpose

To assess the effect of intravitreal and posterior subtenon injections of triamcinolone acetonide (TA) on intraocular pressure (IOP).

Methods

we reviewed 42 consecutive eyes after intravitreal TA injection (IVTA) and 43 eyes following posterior subtenon TA injection (PSTA). All cases had a minimum follow-up time of three months. After injection, the value and time of the maximal IOP, the amount of IOP elevation and the needs of the medication were assessed.

Results

The IOP increased significantly (p<0.001) from 16.3±2.5 mmHg preoperatively to a mean maximum of 21.7±5.3 mmHg in the IVTA group, and from 15.3±4.5 mmHg to 20.6±3.0 mmHg in the PSTA group. An elevation in the IOP of more than 5 mmHg from the baseline IOP was seen in 52.4% of the IVTA group at a mean time of 3.1 weeks postoperatively, and 44.2% of the PSTA group displayed an IOP elevation at 5.9 weeks.

Conclusions

Both developed significant elevations of IOP, but this appeared at a later date in the PSTA group. Careful follow-up after local injection of steroids is necessary.

Anti-TNF therapies in the management of acute and chronic uveitis

Patients with anterior uveitis may be treated with topical therapy alone but patients with posterior uveitis and those with sight threatening complications of anterior uveitis usually require systemic treatment especially if the disease is bilateral. The mainstay of treatment is corticosteroids and additional immunosuppressive agents such as cyclosporin and mycophenolate are used when necessary. There remains a significant cohort of patients in whom this therapy is either not tolerated or is ineffective. The use of the anti-tumour necrosis factor (TNF) antibodies has been very successful in controlling other immune-mediated disorders such as rheumatoid arthritis and has subsequently been extended to use in other arthritidies and other disorders such as psoriasis and Crohn's disease. TNF is known to play a key role in ocular inflammation as shown by animal studies and its detection in the ocular fluids of inflamed eyes in man. In some disorders all types of anti-TNF antibodies have similar efficacy but that does not appear to be the case with uveitis where infliximab is at present looking to be more effective than etanercept. The data on the use of anti-TNF drugs in uveitis is presented together with new data on its role as a steroid sparing agent.

Performing vitreous biopsy by perfluorocarbon-perfused vitrectomy

PURPOSE

To evaluate the safety and efficacy of perfluorocarbon-perfused vitrectomy (PCPV) as a novel technique in obtaining a large undiluted vitreous biopsy.

DESIGN

Cross-sectional interventional study.

METHODS

Patients with undiagnosed posterior uveitis scheduled for vitreous biopsy underwent PCPV. A syringe containing 5 ml of perfluorocarbon liquid (PCL) was connected to the infusion line. Aspiration of the central and superior vitreous was initiated with simultaneous infusion of the PCL.

RESULTS

Twenty eyes of 20 patients were included in this study. The mean +/- SD amount of PCL used in each eye was 4.50 +/- 0.69 ml. The volume of vitreous sample obtained in each eye was 2.25 +/- 0.413 ml. No complications occurred.

CONCLUSIONS

PCPV is a safe and effective method for obtaining large undiluted vitreous biopsy.

Experimental autoimmune uveitis induced by immunization with retinal pigment epithelium-specific 65-kDa protein peptides

PURPOSE

To investigate the pathogenic potential and sites of retinal pigment epithelium-specific 65-kDa protein (RPE65) for inducing experimental autoimmune uveitis (EAU) in Lewis rats.

METHODS

Twenty-six peptides were chemically synthesized based on the amino acid sequences of human RPE65. These peptides spanned the entire RPE65 sequence. Each peptide was injected into a footpad and the peritoneum of Lewis rats. The eyes were examined by slit-lamp biomicroscopy, and the findings were correlated with the histological findings. The serum antibody titer and lymphocyte reactivity against each peptide was also determined by enzyme-liked immunosorbent assay (ELISA) and lymphocyte proliferation assay, respectively.

RESULTS

Active immunization of rats resulted in the induction of EAU with 14 (3 severe and 11 mild) of the 26 peptides. The clinical course of the EAU was similar to that induced by the injection of retinal antigens such as S-antigen or inter-photoreceptor retinoid binding protein (IRBP). However, the histopathologic changes differed from the EAU induced by these retinal antigens. The inflammation was induced mainly from the retinal pigment epithelium (RPE) and the choroid, while the retina was relatively well-preserved except for some granulomatous changes adjacent to the RPE.

CONCLUSIONS

Active immunization with peptides making up RPE65 will induce EAU. RPE65 has multiple EAU-inducing sites for Lewis rats.

Administration of a peptide inhibitor of alpha4-integrin inhibits the development of experimental autoimmune uveitis

PURPOSE

Recruitment of lymphocytes into the retina and to the vitreous during the development of experimental autoimmune uveitis (EAU) is governed by factors such as the state of activation of inflammatory cells and the repertoire of adhesion molecules expressed by the local vascular endothelia. alpha4 Integrins and their receptors play an important role during homing of cells to the inflammatory site. In the present study, the effect of alpha4-integrin inhibitor on the development of EAU was investigated.

METHODS

EAU was induced either by immunizing B10.RIII mice with the 161-180 peptide or by adoptive transfer of interphotoreceptor retinoid-binding protein (IRBP)-specific uveitogenic T cells. Animals were treated with an active peptide inhibitor (alpha4-api) or a peptide control at different time points after induction of disease. EAU was evaluated by histology 21 to 49 days after immunization. Antigen-specific cell proliferation was evaluated by thymidine incorporation. Cytokine synthesis in culture supernatants and anti-IRBP-specific serum IgG1 and IgG2a were evaluated by ELISA. Delayed-type hypersensitivity was evaluated by ear challenge 2 days before the termination of the experiment.

RESULTS

Treatment with alpha4-api had a significant ameliorating effect on EAU. The anti-IRBP antibody response and cellular proliferation were not affected by the treatment, whereas delayed-type hypersensitivity was significantly diminished. Cytokine synthesis was not changed by treatment, except for a decrease in IL-10 levels.

CONCLUSIONS

The results show that small-molecule inhibitors of alpha4-integrins can act therapeutically in EAU, possibly by interfering with cell adhesion events involved in the development of the disease.

Anti-CD137 mAb treatment inhibits experimental autoimmune uveitis by limiting expansion and increasing apoptotic death of uveitogenic T cells

PURPOSE

To explore the role of CD137 in the pathogenesis of experimental autoimmune uveitis (EAU) and to compare the inhibitory mechanism of anti-CD137 mAb with other costimulatory blockers.

METHODS

EAU was induced in B10RIII mice, either by immunization with a uveitogenic peptide, IRBP161-180, derived from the interphotoreceptor retinoid-binding protein, or by adoptive transfer of IRBP161-180-specific T cells. The effect of an agonistic anti-CD137 mAb (2A) on the in vivo induction of disease was studied. Subsequently, the mechanism by which anti-CD137 mAb inhibits uveitogenic T-cell activation was investigated, by using the adoptive transfer of T cells derived from anti-CD137 mAb-treated mice, and in vitro, using the proliferative response and apoptotic cell death of IRBP-specific T cells from anti-CD137 mAb-treated mice.

RESULTS

Administration of anti-CD137 mAb prevented the development of de novo induced uveitis, but not that induced by adoptive transfer of pathogenic T cells. Furthermore, anti-CD137 mAb treatment of the animals resulted in decreased expansion of uveitogenic T cells, accompanied by increased activated cell death and resistance to reinduction of uveitis.

CONCLUSIONS

CD137 plays a critical role in the induction, rather than the effector, phase of the disease. Different costimulatory molecules have different effects on the activation of autoreactive T cells by acting in different phases of T-cell activation.

Contribution of TNF-alpha to leukocyte adhesion, vascular leakage, and apoptotic cell death in endotoxin-induced uveitis in vivo

PURPOSE

To investigate the effect of TNF-alpha on leukocyte adhesion, vascular leakage, and apoptotic cell death in endotoxin-induced uveitis (EIU) in the rat.

METHODS

EIU was induced in Long-Evans rats by a single footpad injection of lipopolysaccharide (LPS; 350 microg/kg) from Salmonella typhimurium. A single injection of recombinant TNF receptor P75 (etanercept) was given subcutaneously 24 hours before the administration of LPS. Twenty-four hours after administration of LPS, leukocyte adhesion was evaluated in vivo with SLO-acridine orange angiography and ex vivo with concanavalin A lectin staining of retinal flatmounts. Neutrophil activation was quantified by a myeloperoxidase activity assay. Vascular leakage was assessed by Evans blue extravasation. Retinal cell death was assessed with TUNEL staining and quantified with a modified ELISA protocol. Involvement of caspase-3 and -8 was determined by M30 antibody staining, Western blot analysis, and a test for enzymatic activity.

RESULTS

Twenty-four hours after the LPS injection, significant increases in leukocyte rolling, adhesion, and activation were observed. In addition, increased levels of apoptosis in the vascular endothelium and the ganglion cell and inner nuclear layers and activation of caspase-8 and -3 were observed. After administration of the TNF-alpha inhibitor, significant reduction in the leukocyte rolling, adhesion, activation, and apoptosis in all the affected layers was observed. The quantitative analysis of vascular leakage revealed a significant decrease after treatment with etanercept. Retinal cell death quantification showed a significant decrease after treatment with the TNF-alpha inhibitor.

CONCLUSIONS

Anti-TNF-alpha treatment reduces the LPS-induced increases in leukocyte rolling, adhesion, and vascular leakage in this rat model of inflammatory uveitis. These results suggest the involvement of TNF-alpha in inflammatory uveitis and its potential use as a therapeutic agent in the reduction of ocular inflammation.

Chemokine and chemokine receptor expression during experimental autoimmune uveoretinitis in mice

BACKGROUND

Chemokines act as chemoattractants and activators of specific leukocytes at the site of inflammation. In this study, we investigated serial expression of chemokines and chemokine receptors in the eye with experimental autoimmune uveoretinitis (EAU) using RNAse protection assay, and confirmed their expression by immunohistochemical staining.

METHODS

B10.A mice were immunized with 50 micro g of interphotoreceptor retinoid binding protein (IRBP) emulsified in complete Freund's adjuvant in order to induce EAU. The eyes were enucleated 0, 7, 14 and 21 days after IRBP immunization to analyze mRNA expression of chemokines and chemokine receptors in the posterior segment. In addition, expression of IP-10 and CXCR3 was analyzed by immunohistochemistry.

RESULTS

The gene expression of RANTES, IP-10, and MCP-1 was upregulated on day 14 after immunization (early stage of EAU). The expression of chemokine receptors (CCR2 and CCR5) associated with Th1-type T cells correlated with their appropriate ligands. Furthermore, immunohistochemical study showed that IP-10 and CXCR3, the receptor for IP-10, were strongly expressed in the posterior segment of the eyes from mice with EAU.

CONCLUSION

These results suggest that RANTES, IP-10 and MCP-1 may contribute to the recruitment of Th1-type T cells into the eye during the development of EAU in mice.

Leukocyte trafficking in experimental autoimmune uveitis: breakdown of blood-retinal barrier and upregulation of cellular adhesion molecules

PURPOSE

To clarify the order of events occurring in the breakdown of the blood-retinal barrier (BRB) in experimental autoimmune uveoretinitis (EAU) and in particular to study the relationships between increased vascular permeability, upregulation of endothelial cell adhesion molecules, and leukocyte adhesion and infiltration during EAU.

METHODS

B10.RIII mice were immunized with human interphotoreceptor retinoid binding protein (IRBP) peptide 161-180. Changes in the retinal microvasculature were examined on days 3, 6, 7, 8, 9, 10, 16, and 21 postimmunization (pi). Evans blue dye was administered intravenously to assess vascular permeability. Expression of intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, P-selectin, E-selectin, and platelet endothelial cell adhesion molecule (PECAM)-1 was evaluated by in vivo administration of antibody and subsequent immunostaining of retinal wholemounts. Lymphocytes from inguinal lymph nodes of normal and chicken ovalbumin (OVA)- or IRBP peptide-immunized mice at day 5, 6, 7, 8, and 15 pi were labeled in vitro with calcein-AM (C-AM) and infused intravenously into syngeneic recipient mice, which had been immunized with peptide at the same corresponding time point. Wholemount preparations of retinas were observed 24 hours later by confocal microscopy to determine the adhesion and infiltration of lymphocytes.

RESULTS

The first observation of an increase in vascular permeability occurred at day 7 pi and was restricted to focal areas of the retinal postcapillary venules of the inner vascular plexus. This progressively extended to the outer vascular plexus at day 9 pi. Specific adhesion of leukocytes to the endothelium of retinal venules of the inner vascular plexus was first observed at day 6 pi. Leukocyte extravasation into the retinal parenchyma from these vessels began at day 8 pi and extended to the outer vascular plexus at day 9 pi. The expression of adhesion molecules increased progressively during the development of EAU. In particular, the adhesion molecules ICAM-1, P-selectin, and E-selectin were expressed predominately in retinal venules, the sites of BRB breakdown, cell adhesion, and extravasation, from day 7 pi. The increases in expression of ICAM-1 and P-selectin were associated both spatially and temporally with breakdown of the BRB, cell adhesion, and extravasation. No increase in expression of P-selectin and ICAM-1 was observed in either the mesenteric vessels of EAU mice or the retinal vessels of OVA-immunized mice.

CONCLUSIONS

The sequence of events in EAU appears to be focal adhesion of leukocytes to discrete sites on postcapillary venules, followed by upregulation of adhesion molecules, especially ICAM-1 and P-selectin, and breakdown of the BRB, leading to transendothelial migration of leukocytes and recruitment of large numbers of cells to the retinal parenchyma. These changes occur over a short period of 6 to 9 days pi and initiate the process of tissue damage during the following 2 to 3 weeks.

[Acute posterior or multifocal placoid pigment epitheliopathy]

The paper presents a clinical case of Acute Posterior Multifocal Placoid Pigment Epitheliopathy and the specific diagnosis problems of this case. Being a less frequent disease the common aspects are emphasized as well as the latest concepts about this syndrome.

Immunopathology of the noninfectious posterior and intermediate uveitides

The posterior and intermediate uveitides share an underlying immune etiology; however, they can be clinically and immunopathologically distinguished. Although the initiating stimuli for posterior and intermediate uveities are not known, it is believed that an exogenous agent (such as a bacterium or a virus) or an endogenous molecule may induce disease. In either case, T-helper lymphocytes in conjunction with human leukocyte antigens are likely to be involved. This review examines the epidemiology, histology, immunopathology, and theories of pathogenesis of several posterior and intermediate uveitides, including sympathetic ophthalmia, Vogt-Koyanagi-Harada syndrome, Behçet's disease, sarcoidosis, intermediate uveitis, white dot syndromes, and birdshot retinochoroidopathy.

Syphilitic Posterior Uveitis: Correlative Findings and Significance

Twenty-one patients with syphilitic posterior uveitis were investigated retrospectively to study the disease spectrum, associations with neurosyphilis, and therapeutic implications. Ophthalmologic manifestations of syphilitic posterior uveitis are differentiated into acute and chronic uveitides. The several distinct acute uveitic syndromes are usually florid and are associated with early syphilis, with VDRL-positive syphilitic meningitis, and frequently with human immunodeficiency virus coinfection. The chronic posterior uveitides are often insidious, a manifestation of late syphilis, and associated commonly with subclinical neurosyphilis. All patients with acute cases and 54% of patients with chronic cases in our study received penicillin therapy appropriate for neurosyphilis. The frequent association of syphilitic posterior uveitis with neurosyphilis and the analogous spirochetal sequestration beyond the blood-brain and the blood-ocular barriers suggest that all patients with syphilitic posterior uveitis, irrespective of ocular disease intensity, should undergo evaluation of cerebrospinal fluid and be treated with penicillin regimens appropriate for neurosyphilis.

Birdshot retinochoroidopathy: measurement of the posterior fundus spots and macular edema using a retinal thickness analyzer, before and after treatment

PURPOSE

To measure the retinal thickness in the macular area and at the typical fundus spots in a patient with birdshot retinochoroidopathy, using the retinal thickness analyzer (RTA), a new image analyzer involving laser-slit biomicroscopy, and to quantify the changes after systemic corticosteroid therapy.

CASE REPORT

A 54-year-old man with posterior uveitis underwent visual acuity measurement, fluorescein and indocyanine green (ICG) angiographies, optical coherence tomography (OCT) and RTA measurements before and after steroid treatment.

RESULTS

The thickness at the birdshot spots measured with RTA remained unchanged after treatment, but the thickness at the fovea decreased in both eyes. Fluorescein and ICG angiographies and OCT showed no change with treatment.

CONCLUSIONS

RTA seems a more sensitive method for assessing changes in macula thickness in the course of birdshot retinochoroidopathy and can help document the effect of treatment.

Intravenous immunoglobulin (IVIg) for the treatment of birdshot retinochoroidopathy

Intravenous polyclonal immunoglobulin (IVIg) treatment has been successfully used in a number of autoimmune conditions. Birdshot retinochoroidopathy (BRC) is a bilateral autoimmune posterior uveitis which, in its progressive form, frequently requires immunosuppressive therapy. We report a clinical study aimed at determining the tolerance and efficiency of IVIg treatment in patients with active BRC. The study was conducted in an open manner. Eighteen patients were included. The initial visual acuity (VA) was < or =20/30 in 26 eyes, 20/25 in five eyes, and 20/20 in five eyes. IVIg was given as sole treatment at 1.6 g/kg every four weeks for six months, followed by injections of 1.2-1.6 g/kg at six to eight-week intervals. The mean follow-up was 39 months, ranging between 12 and 53 months. The results showed that the final VA of the 26 eyes with an initial VA of < or =20/30 was increased by two lines or more in 14 eyes (53.8%) and decreased in two (7.7%). Of the five eyes with an initial VA of 20/25, four had improved to 20/20 and one remained stable. Of the five eyes with an initial VA of 20/20, four remained stable and one deteriorated to 20/25. When present, macular edema was improved in half of the eyes on fluorescein angiography. Benign side effects were observed in 12 patients: moderate transient arterial hypertension (7), headache (6), eczematous lesions (6), and hyperthermia (4). The results suggest that IVIg may represent a safe alternative therapy for patients with BRC.

Macrophages and dendritic cells in IRBP-induced experimental autoimmune uveoretinitis in B10RIII mice

PURPOSE

To investigate the characteristics of the mononuclear cell infiltrate in murine experimental autoimmune uveoretinitis (EAU).

METHODS

EAU was induced by immunization with bovine interphotoreceptor retinal binding protein (IRBP) in Freund's complete adjuvant (subcutaneous injection) and pertussis toxin (intraperitoneal injection) in B10RIII mouse. Then animals were killed on days 7, 9, 12, 15, 20, 26, and 39 after immunization. Eyes were processed for hematoxylin and eosin staining to characterize the disease and to assess the severity and extent of the EAU. Single and dual immunohistochemical staining in various combinations with monoclonal antibodies against CD45, CD4, CD8, major histocompatibility complex (MHC) class II, CD11c, NLDC-145, and a variety of macrophage markers was performed.

RESULTS

The authors' results showed that vitritis, vasculitis and perivasculitis, retinal detachment, and granuloma formation in retina and choroid were the predominant features of IRBP-induced B10RIII mice EAU. Immunohistologic results showed that CD4+ T cells and macrophages were the main infiltrating cells in retina and choroid throughout the entire course of the disease. MHC class II negative macrophages expressing antigens reacting with MOMA-2, F4/80, sialoadhesin, and CD11b were prominent during the peak phase of tissue damage in the retina and choroid. Dendritic cells (DCs) characterized by dual positivity for MHC class II and CD11c and negative for sialoadhesin appeared at time of disease onset and continued to be recruited during the inflammatory process. DCs at the site of inflammation were NLDC-145 weak and CD8 negative, indicating that they were of the myeloid rather than the lymphoid lineage.

CONCLUSIONS

The results suggest that EAU in B10RIII mice is initiated by local-infiltrating, dendritic antigen-presenting cells, whereas tissue damage is associated with sialoadhesin-positive, phagocytic nonantigen-presenting macrophages during the effector stage.

The role of costimulatory molecules B7-1 and B7-2 in mice with experimental autoimmune uveoretinitis

BACKGROUND

Onset of experimental autoimmune uveoretinitis (EAU) is believed to involve a CD4-positive type 1 T helper cell (Th1) immune response, with inhibition involving a Th2 immune response. Development of Th1 and Th2 responses involves the participation of the costimulatory molecules B7-1 and B7-2, respectively. The purpose of this study was to investigate the role of B7-1 and B7-2 in the EAU model in mice.

METHODS

B10.A mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) and given daily intraperitoneal injections of either phosphate-buffered saline (control), mouse monoclonal antibody (mAb) to B7-1, mAb to B7-2, or mAb to both B7-1 and B7-2. Eyes were evaluated by histopathological criteria and cytokines were assayed in culture medium of IRBP-stimulated lymphocytes. Cellular immune responses were measured by cell proliferation assay under IRBP stimulation.

RESULTS

Rates of EAU onset were 5/10 (50%) for control mice, 1/9 (11%) for mice treated with anti-B7-1 mAb, 5/6 (83%) for mice treated with anti-B7-2 mAb, and 2/6 (33%) for mice treated with both anti-B7-1 and anti-B7-2 mAb. Mean histopathological severity scores were 2. 4+/-0.8, 1.0+/-0, 2.6+/-1.0, and 1.0+/-0, respectively. Production of IL-5 was significantly increased in mice treated with anti-B7-1 mAb, while IFN-gamma was increased in mice treated with anti-B7-2 mAb. Spleen cell proliferation was significantly reduced in mice treated with anti-B7-1 mAb.

CONCLUSIONS

These results suggest that the costimulatory molecules B7-1 and B7-2, via their influence on generating Th1 and Th2 immune responses, play an important role in the clinical outcome of EAU in mice immunized with IRBP.

Nanophthalmic uveal effusion syndrome after prophylactic laser treatment

PURPOSE

We report a case of nanophthalmic uveal effusion syndrome (NUES) with total exudative retinal detachment (RD) after prophylactic argon laser (AL) treatment. The RD subsided and eventually resolved with i.v. steroid therapy.

METHODS

A 45-year-old woman was referred to us with NUES and total exudative RD after prophylactic AL treatment for retinoschisis performed elsewhere. The patient had been scheduled for surgical intervention and was given i.v. prednisolone.

RESULTS

Two days after starting i.v. prednisolone, the subretinal fluid partially resolved. Intervention had therefore been postponed. After 15 days the RD almost disappeared and vision improved to 20/400. Ten days later the macula was flat and vision was 20/200. At the six-month follow-up visit vision was 20/40.

CONCLUSIONS

To our knowledge this is the first report of NUES and total exudative RD following AL treatment that resolved with i.v. steroid therapy alone. Since the AL treatment clearly seemed to play a role in the pathogenesis of the NUES and associated RD we strongly advise careful assessment of the risk/benefit ratio of prophylactic laser treatment in nanophthalmic patients. Although sclerectomy and vortex vein decompression are well-established techniques, we believe steroid therapy might be tried before proceeding to surgery.

[Specific features of tuberculous uveitis pathomorphology]

There have been great changes in the clinical picture and course of ocular tuberculosis in the 90s versus the 70-80s. There has been a upward trend in the incidence of ocular tuberculosis in the population, in children and teenagers in particular. Patients with tuberculous uveitis involving the posterior eye makes up over 70%. A specific eye tissue inflammatory process is mainly exudative and infiltrative with rapid development of the complications masking a tuberculous focus, which hampers treatment and causes a significant decrease in visual functions.

Effects of systemically applied allopurinol and prednisolone on experimental autoimmune uveitis

PURPOSE

To compare the effects of allopurinol to those of prednisolone on the oxidative tissue damage and inflammatory response in experimental autoimmune uveitis (EAU).

METHODS

Experiments were performed using 27 male Lewis rats. EAU was induced by means of crude retina extract, Freund's adjuvant and pertussis toxin. One group of animals served as controls and two groups were treated systemically, one with allopurinol and one with prednisolone. At the end of the experiments lipid peroxides (LPO), myeloperoxidase activity (MPO), and histological changes were determined in the retinal tissue. LPO were measured by two different methods [thiobarbituric acid reactive substances (TBARS) and malondialdehyde-like substances].

RESULTS

Allopurinol led to a significant reduction in LPO and MPO levels. The steroid treatment also resulted in a significant reduction in MPO activity but LPO were significantly reduced only when measured as TBARS. Histological changes were significantly reduced by allopurinol only.

DISCUSSION

Allopurinol is more effective than prednisolone in treating EAU. Its efficacy can be explained by the antioxidative/antiinflammatory and probably immunological action. The antiinflammatory effects of prednisolone are not sufficient to reduce the tissue damage. Allopurinol promises to be a useful alternative to steroids in the treatment of uveitis.

T cell traffic and the inflammatory response in experimental autoimmune uveoretinitis

PURPOSE

To quantify S-antigen-specific (S-Ag) T cells in the retina after adoptive transfer, and to evaluate their role in the initiation and progress of destructive ocular inflammation in experimental autoimmune uveoretinitis (EAU).

METHODS

Lewis rats were administered 10 x 10(6) S-Ag-specific T cells from the SP35 cell line or 10 x 10(6) concanavalin A-stimulated syngeneic spleen cell lymphoblasts labeled with lipophilic PKH26 fluorescent dye immediately before intravenous inoculation. Labeled cells in each retina were counted at various times from 4 to 120 hours after cell transfer by fluorescence microscopic analysis of each dissociated retina. Recipient eyes were examined within the same period by light and confocal microscope.

RESULTS

SP35 T cells showed a biphasic distribution in the retina. The first peak of 160 cells/retina was noted at 24 hours. A steady decline of labeled cells at 48 and 72 hours was followed by a rapid increase at 96 and 120 hours. Concanavalin A-stimulated, control-labeled cell populations showed an identical peak at 24 hours but a persistent decline thereafter; only two or three T cells were present in each retina at 120 hours. Concurrent inoculation of SP35 cells and nonspecific T cell blasts did not produce more SP35 cells than control cells in the retina at any time. Microscopic analysis showed mononuclear cell infiltration of the iris, ciliary body, and aqueous humor at 48 hours, which intensified rapidly and persisted through 120 hours. Retinal inflammation did not begin until 80 hours. Mononuclear cell adherence to vascular endothelium and perivascular macrophage infiltration of the innermost layers progressed to edema, and profound destructive inflammation and loss of retinal stratification were observed at 120 hours.

CONCLUSIONS

There is no evidence of a blood-ocular or blood-retinal barrier to activated T cell blasts. Autologous S-Ag does not provoke a more rapid entry of specific T cells at that site. The data confirm that anterior segment inflammation precedes retinal inflammation, even though S-Ag-specific T cells were present in the retina within a few hours after cell transfer. Because S-Ag is clearly present in the retina, delay in antigen presentation at that site may account for the temporal difference between retinal and anterior segment inflammation.

Schematic interpretation of indocyanine green angiography in posterior uveitis using a standard angiographic protocol

OBJECTIVE

Indocyanine green angiography (ICGA) detects fluorescence produced by the ICG molecule in the near infrared wave lengths showing choroidal vascular structures. Indocyanine green angiography may prove useful in the workup of uveitis with choroidal involvement. The authors' purpose was to test a standardized ICGA protocol for posterior uveitis to gather systematic and comparable data and to design a schematic approach for the interpretation of angiographic signs.

DESIGN

The proposed ICGA procedure included the search for preinjection fluorescence. In the early phase of ICGA (until +/- 2-3 minutes postinjection), posterior pole frames were taken to detect abnormalities in the retinal and choroidal arteriovenous circulation patterns. During the intermediate phase (12 +/- 3 minutes), posterior pole frames and eight 360 degrees panorama frames were taken to detect fluorescence abnormalities in the background impregnation of the choroid, the same sequence being repeated in the late phase (40 +/- 10 minutes). A cohort of more than 300 patients was analyzed in this standard fashion in 2 centers. PARTICIPANTS AND MAIN OUTCOME MEASURE: Determination of ICGA features and the proposed schematic approach for ICGA interpretation were based on the analysis of 109 cases of posterior uveitis with a well-determined diagnosis.

RESULTS

For uveitis, the intermediate and late phases of ICGA were found to yield the most valuable information showing either ICG hyperfluorescence or hypofluorescence or both. The ICG hyperfluorescence, always reflecting increased leakage or staining but not window defects because there is no pigment epithelium screen in ICGA, could originate either from increased leakage of the choriocapillaris, the large choroidal, or the retinal vessels. The characteristic ICG hypofluorescent dark dots indicating impairment of physiologic impregnation of the choroid could take at least five different patterns.

CONCLUSION

To date, ICGA features still are difficult to interpret. The proposed standardized ICGA protocol and schematized interpretation for posterior uveitis will help determine ICGA semiology for these disorders and might give new insights into their pathophysiology.

Nasal administration of retinal antigens maintains immunosuppression of uveoretinitis in cyclosporin-A-treated Lewis rats: future treatment of endogenous posterior uveoretinitis?

PURPOSE

Current treatment of autoimmune endogenous posterior uveoretinitis (EPU) is limited by drug toxicity, unpredictable relapses on dose reduction and resistance to therapy. Administration of autoantigens via gastrointestinal or respiratory mucosa prior to antigen exposure induces immune hyporesponsiveness (mucosal tolerance) to further antigen sensitisation. In this study we assessed whether mucosal tolerance induction was possible after immunisation with retinal antigens in experimental autoimmune uveoretinitis (EAU) in animals that were short-term immunosuppressed with cyclosporin A (CsA) to determine whether mucosal administration of retinal antigens can maintain immunosuppression in sensitised and immunosuppressed individuals.

METHODS

Female Lewis rats were immunised with retinal extract (RE) and then treated as follows. Group 1 received no specific therapy and served as control; group 2 were fed CsA from day 7 to day 20 post-immunisation; group 3 received inhalational tolerance therapy with RE in addition to CsA; tolerance therapy was continued after day 20 when CsA was stopped. Experiments varying the timing and dosage of both tolerising and immunising antigen were also performed, the details of which are described. Incidence, day of onset and clinical activity were recorded and histopathological assessment of intraocular inflammation, in particular the extent of autoimmune target-organ damage, was graded semiquantitatively.

RESULTS

Compared with controls and group 2, group 3 showed both a marked delay in disease onset and a reduction in disease severity. This effect was both dose and dose-timing dependent. Tissue damage assessed in terms of preservation of rod outer segments was significantly less in group 3.

CONCLUSIONS

The success of combination therapy, clinically, remains unknown at present but these results support continuing present clinical trials of mucosal tolerance therapy and in particular have future implications for either maintaining or inducing immunosuppression in autoimmune diseases in combination with present immunosuppressive therapies.

Appearance of birdshot retinochoroidopathy in a patient with myelodysplasia syndrome

PURPOSE

To report the appearance of birdshot retinochoroidopathy in a patient with myelodysplasia syndrome.

METHOD

Case report of a healthy 62-year-old woman who was fortuitously noted to have multiple atrophic spots in the posterior choroid and retina of each eye.

RESULT

Subsequent medical evaluation included a blood cell count that disclosed pancytopenia, with a diagnosis of myelodysplasia made on bone marrow examination.

CONCLUSION

An autoimmune response associated with the underlying myelodysplasia may be responsible for the appearance of atrophic retinal and choroidal lesions resembling birdshot retinochoroidopathy.

Apoptosis in patients with posterior uveitis

BACKGROUND

Apoptosis plays a part in the pathogenesis of autoimmune diseases.

OBJECTIVE

To investigate the expression of apoptotic markers in the eyes of patients with uveitis.

METHODS

With the use of immunohistochemical and in situ apoptotic detection techniques, apoptotic molecules (Fas or Fas ligand [FasL]) and nuclear DNA fragmentation were examined in 8 enucleated eyes with Behçet's disease (1), sarcoidosis (1), subretinal fibrosis and uveitis (1), sympathetic ophthalmia (4), and the Vogt-Koyanagi-Harada syndrome (1); in 5 chorioretinal biopsy specimens with acute retinal necrosis (2), multifocal choroiditis (1), sarcoidosis (1), and subretinal fibrosis and uveitis (1); and in 3 normal control eyes.

RESULTS

Fas and FasL were constitutively expressed in the normal human retina, but they were expressed much less in the choroid. Increased expression of Fas and FasL was found in the retina, chorioretinal scar, and choroidal granulomas in uveitic eyes. However, Fas and FasL expression was absent in the biopsy specimens with acute retinal necrosis, and little Fas or FasL was noted on infiltrating lymphocytes. DNA fragmentation was also identified in eyes with chorioretinal scar and gliosis.

CONCLUSIONS

Apoptosis occurs in uveitic eyes and may play a regulatory role in limiting ocular inflammation. In uveitic eyes, a dysregulation of the Fas-FasL apoptotic pathway may lead to gliosis and fibrosis.

Resident and infiltrating cells in the rat iris during the early stages of experimental melanin protein-induced uveitis (EMIU)

Experimental melanin protein-induced uveitis (EMIU) is reported to be a model of anterior uveitis and choroiditis in which the retina is spared. In this study, we chose to compare EMIU with experimental autoimmune uveoretinitis (EAU), a well-recognised model of endogenous posterior uveitis, with regard to the nature and dynamics of the cellular infiltrate in the iris. Female Lewis albino rats were immunised with mixtures of crude retinal extract/complete Freund's adjuvant (CFA) (EAU), phosphate-buffered saline/CFA (controls), or iris melanin/CFA (EMIU) using established protocols. Animals were sacrificed on days 10 and 13 (around disease onset). Following whole body perfusion fixation, irides were dissected from the remainder of the globe. Iris wholemount preparations were then subjected to immunohistochemical analysis in order to investigate both the dynamics of infiltrating leukocytes and the effects of the inflammatory changes on resident immune cells in the iris. The nature of the cellular infiltrate in both EMIU and EAU models was essentially similar, namely there was a rich infiltrate of EDI+ mononuclear cells, Ox42+ neutrophils and T cells. Resident tissue macrophages (ED2+) were slightly below normal densities in the iris of EAU animals and marginally elevated in EMIU animals, MHC class II (Ia) staining, associated in the normal eye with dendritic cells (DC), was considerably elevated in EMIU. It is likely that this was due to both increased DC numbers and an influx of Ia+ exudate macrophages. No striking difference was found in the nature and phenotype of the cellular infiltrate in the iris at the onset of the disease in these two models of uveitis (EAU and EMIU). This suggests that the anterior segment inflammation in both models represents non-specific changes secondary to cytokine release associated with interaction of activated antigen-specific T cells and target antigens, namely retinal photoreceptors in EAU and uveal tract melanin-containing cells in EMIU. Alternatively, it may suggest that antigen-presenting cells resident in the iris and ciliary body in normal eyes have access to ocular antigens on both sides of the blood-ocular barrier and are capable of activating circulating antigen-specific T cells in these models.

Tacrolimus-rapamycin combination therapy for experimental autoimmune uveoretinitis

Tacrolimus and rapamycin both belong to a new family of immunosuppressants, immunophilin ligands, but the mechanisms by which they inhibit T cell activation are different. Therefore, we tested the immunosuppressive effects of combination therapy with low doses of tacrolimus and rapamycin on experimental autoimmune uveoretinitis (EAU) in rats. Male Lewis rats, immunized with S-antigen (S-Ag) were given intraperitoneal injection of the combined drugs for 14 days after the immunization with S-Ag. Effects were evaluated by clinical observations, histological examination and immune response. The combination therapy with tacrolimus (0.1 mg/kg per day) and rapamycin (0.03 mg/kg per day) achieved 100% suppression of clinical EAU and 66.7% suppression of histological EAU; tacrolimus combined with a higher dose of rapamycin (0.1 mg/kg per day) caused 100% suppression clinically and histologically. Therapy with either drug alone achieved only partial suppression: tacrolimus alone (0.1 or 0.2 mg/kg per day) or rapamycin alone (0.03-0.2 mg/kg per day). Doubling the dose of either drug produced only 16.7% suppression with rapamycin or 50% suppression with tacrolimus. The serum antibody levels to S-Ag and proliferative response of lymphocytes to S-Ag were also significantly suppressed by the combination therapy with low doses of tacrolimus and rapamycin.

In vivo quantification of leukocyte behavior in the retina during endotoxin-induced uveitis

PURPOSE

The interaction between leukocytes and vascular endothelial cells plays an important role in various inflammatory disorders. This study evaluated leukocyte behavior in the retina during endotoxin-induced uveitis (EIU) in vivo.

METHODS

EIU was induced in female Lewis rats by footpad injection of lipopolysaccharide (LPS). The time-course changes of retinal leukocyte behavior were followed at 1.5, 3, 4.5, 6, 12, 24, 48, 72, and 120 hours after LPS treatment using acridine orange digital fluorography, consisting of high-resolution images from a scanning laser ophthalmoscope and a fluorescent nuclear dye of acridine orange.

RESULTS

Major retinal vessels were significantly dilated (P < 0.05) at 4.5 hours after LPS injection. The vasodilation, marked in veins, became maximum at 24 hours and subsided at 72 hours. Leukocytes were observed rolling along the walls of major veins at 4.5 hours. The number of rolling leukocytes gradually increased and reached a peak level of 33.8 +/- 3.4 cells/minute per major vein at 12 hours. Leukocyte rolling was still observed at 72 hours. No rolling of leukocytes was observed along the arterial walls throughout any experiments. The velocities of rolling leukocytes were determined at 6, 12, 24, and 48 hours. The leukocyte rolling velocity at 6 hours was significantly slower (33.3 +/- 2.8 microns/second, P < 0.05) than at the other three times (average, 46.6 microns/second). Cellular infiltration into the vitreous cavity was detected at 24 hours and reached its maximum at 48 hours.

CONCLUSIONS

This study demonstrates that it is possible to evaluate EIU by investigating retinal leukocyte behavior and that vasodilation of major retinal vessels and leukocyte-endothelial interactions precede inflammatory cell emigration into the vitreous. This method may be useful to quantify the severity of inflammation in EIU.

Resident and infiltrating immune cells in the uveal tract in the early and late stages of experimental autoimmune uveoretinitis

PURPOSE

To investigate the dynamics of resident and infiltrating immune cells in the choroid and iris during the early and late stages of experimental autoimmune uveitis (EAU) in Lewis rats.

METHODS

Uveoretinitis was induced by footpad injection of crude retinal extract and complete Freund's adjuvant with concurrent intraperitoneal injection of Bordetella pertussis. Five experimental (EAU) and five control animals (adjuvant alone) were studied at days 5, 7, 9, 11 (prodromal stage) and 42 (late stage) after immunization. Five normal animals and five animals injected with B. pertussis alone served as further controls. Immunohistochemical localization of resident macrophages, major histocompatibility complex class II (Ia)+ dendritic cells (DC), infiltrating mononuclear cells, and T cells was performed on wholemounts of isolated choroidal and iris tissue.

RESULTS

Double immunolabeling confirmed the presence of distinct networks of macrophages (591 +/- 52 cells/mm2) and DC (746 +/- 38 cells/mm2) in the rat choroid. No marked qualitative and quantitative changes were observed in the density or morphologic appearance of ED2+ resident tissue macrophages in the choroid and iris before clinical onset of ocular disease. On day 11, infiltration of ED1+ monocytes had occurred in the iris but not in the choroid; however, marked infiltration of T cells was evident in both choroid (286 +/- 161 cells/mm2) and iris (196 +/- 72 cells/mm2). The total density of Ia+ cells was significantly elevated in the choroid (1152 +/- 192 cells/mm2) at day 11, and small, round Ia+ cells were two to three times more frequent than normal at both sites. The density of T cells and Ia+ cells remained significantly elevated in the choroid and iris in the late stages of EAU.

CONCLUSIONS

These data suggest resident uveal tract macrophages undergo no significant alteration in density in the early stages of EAU and that the earliest site of mononuclear cellular infiltrate in EAU occurs in the iris. The increased total density of Ia+ cells in the choroid on day 11 and the presence of significantly increased numbers of small, round Ia+ cells in the iris and choroid may represent increased trafficking of DC in the eye during uveoretinitis. Furthermore, the raised numbers of Ia+ cells, concurrent with the influx of T cells, suggests Ia+ DC and macrophages may act as local antigen-presenting cells in the induction of uveoretinitis.

Inflammatory opacities of the vitreous in rifabutin-associated uveitis

PURPOSE

To describe rifabutin-associated uveitis with opacities in the inferior and posterior vitreous in three patients with acquired immunodeficiency syndrome.

METHOD

Case reports of the three patients are presented.

RESULTS

The patients, who were being treated with rifabutin and fluconazole, developed anterior and posterior uveitis. The posterior uveitis was characterized by white-yellow inflammatory opacities located in the inferior and posterior vitreous. Discontinuation of rifabutin and the start of topical corticosteroid therapy resulted in improvement of the uveitis and visual acuity.

CONCLUSION

Recognition of rifabutin-associated uveitis with opacities in the inferior and posterior vitreous may prevent unnecessary invasive diagnostic and therapeutic procedures.

Anti-tumor necrosis factor alpha therapy suppresses the induction of experimental autoimmune uveoretinitis in mice by inhibiting antigen priming

PURPOSE

Experimental autoimmune uveoretinitis (EAU) serves as a model for several immune-mediated diseases that affect the eye in humans. Previous studies indicated that tumor necrosis factor alpha (TNF-alpha) has an important proinflammatory role in EAU and possibly in human uveitis. In this study, the authors investigated the effect of anti-TNF-alpha therapy on EAU in mice.

METHODS

Experimental autoimmune uveoretinitis was induced in B10.A mice by immunization with interphotoreceptor retinoid-binding protein (IRBP). The mice were treated with 100 or 300 microliters rabbit antiserum or polyclonal antibodies to human TNF-alpha. The treatment spanned either the afferent or the efferent stage of EAU (days -1, 1, 3, 5, 7, or days 8, 10, 12, 14, 16, respectively). Control animals were injected with preimmune rabbit serum at the corresponding times or were not treated. Three weeks after immunization, EAU was assessed by clinical evaluation and by histopathology. Immunologic responses were assessed by delayed-type hypersensitivity (DTH), lymphocyte proliferation to IRBP, and relative abundance of IRBP-primed splenocytes.

RESULTS

The treatment with rabbit anti-TNF-alpha serum significantly ameliorated disease when given during the afferent stage but had no effect when given during the efferent stage of EAU. The effect on DTH, lymphocyte proliferation, and abundance of antigen-reactive cells roughly paralleled the effect on disease.

CONCLUSIONS

Neutralization of systemic TNF ameliorates EAU. The effectiveness of afferent treatment in comparison to the treatment during the efferent stage, together with the reduced proliferation and the reduced abundance of IRBP-responsive cells, suggest that interference with afferent-acting processes such as antigen priming is important to achieve protection from EAU by anti-TNF treatment.

Posterior segment ocular manifestations in patients with HLA-B27-associated uveitis

PURPOSE

To describe a series of patients with seronegative arthritic syndromes and HLA-B27-associated uveitis with severe, sight-threatening, posterior segment ocular manifestations.

METHODS

The authors reviewed the records of 29 patients (17.4%) with posterior segment involvement from a cohort of 166 patients with HLA-B27-associated uveitis. The inclusion criteria included individuals with a positive HLA-B27 who had at least one of the following findings: (1) severe vitreous inflammation; (2) papillitis; (3) retinal vasculopathy; or (4) pars plana exudates. The study population comprised 13 men and 16 women with a mean age at onset of uveitis of 35.2 years. The average duration of the uveitis was 5.3 years, and the median follow-up time was 26 months.

FINDINGS

Posterior segment involvement occurred in 34 eyes of the 29 patients. The most common findings included severe and diffuse vitritis in 93.1% of the patients and papillitis in 24 patients (82.7%). Retinal vasculitis occurred in seven patients (24.1%), and pars plana exudates were present in two patients (6.8%). Cystoid macular edema (37.9%) and epiretinal membrane (17.2%) were common causes of visual impairment. Systemic immunosuppressive therapy was required for control of inflammation in 32% of the patients.

CONCLUSION

HLA-B27-associated uveitis may be related to severe, sight-threatening posterior segment manifestations in some patients; this is an under-recognized phenomenon. These patients may require the use of aggressive systemic immunosuppressive therapy to control inflammation and preserve vision.

Murine experimental autoimmune uveoretinitis induced by interphotoreceptor retinoid-binding protein and Klebsiella pneumoniae 03 lipopolysaccharide (K03-LPS): a relation between H-2 haplotype and EAU induction

The pathogenicity of interphotoreceptor retinoid-binding protein (IRBP) in the mouse and H-2 restriction of IRBP-induced experimental autoimmune uveoretinitis (EAU) was tested by repeated immunization using Klebsiella pneumoniae 03 lipopolysaccharide (K03-LPS) as an adjuvant. It was shown that IRBP had a greater capacity to induce EAU than S-antigen. Based on the incidence of EAU induction using B10 congenic mice and other strains, the susceptibility to EAU was, at least in part, controlled by the I-Ak haplotype of the H-2 subregion. The results also indicated that non-major histocompatibility complex (MHC) genes play some role in disease susceptibility.

Retinal pathologic changes in multiple sclerosis

PURPOSE

To describe the ocular pathologic changes in multiple sclerosis (MS), with attention to its effects on the uveal tract and retinal veins.

METHODS

Cases of 26 patients with MS and 3 patients with neuromyelitis optica were reviewed; retinal trypsin digestion was performed on remaining wet tissue for 20 of these patients. Eyes were specifically examined for inflammation of the retinal vessels, uveal tract, retina, optic nerve, and pars plana. Specimens were also examined for atrophy of the optic nerve, ganglion cell, and nerve fiber layers.

RESULTS

Atrophy of the nerve fiber and ganglion cell layers was present in 73% of the cases with MS and correlated with optic nerve atrophy; choroiditis was present in 11.5%; bilateral cyclitis without other foci of inflammation was present in 1 case; and retinal phlebitis was present in 20% (most of which were only identified after trypsin digestion). Optic nerve inflammation was present in two of the patients with neuromyelitis optica.

CONCLUSION

Uveitis and retinal phlebitis are manifestations of MS. Trypsin digestion with microscopic examination is a sensitive method of testing for phlebitis, which may explain why the frequency found in this series is higher than in others. These lesions are similar to the perivenular cuffing that occurs in the central nervous system in MS.

[Posterior uveitis--clinical forms and experimental models]

The author presented contemporary views concerning etiology and clinical forms of endogenous posterior uveitis as well as the experimental models and histopathological studies of these diseases. The similarities between clinical and experimental forms of choroiditis are emphasized.

Role of retinal pigment epithelium in the development of experimental autoimmune uveitis

PURPOSE

To determine the role of retinal pigment epithelium in the induction of S-antigen-induced uveitis by administration of sodium iodate (NaIO3) to selectively damage the retinal pigment epithelium.

METHODS

Forty-four Lewis rats were injected with 60 micrograms of S antigen in complete Freund's adjuvant. On postimmunization day 9 the rats were separated into four groups: three groups received NaIO3 at doses of 50, 25, and 10 mg/kg body weight, respectively, and the fourth group (control) received diluent. In addition, separate groups of animals (three in each group) received various doses of NaIO3 or diluent. All of the animals were killed on day 6 after NaIO3 injection, and the eyes were enucleated and submitted for light and electron microscopic examination. In addition, two groups of Lewis rats (6 in each group) were immunized with 0.5 ml of guinea pig spinal cord homogenate in complete Freund's adjuvant to induce experimental allergic encephalomyelitis. On postimmunization day 7, one group received NaIO3 at a dose of 50 mg/kg body weight, whereas the other group received diluent. All animals were killed between days 12 and 14, and spinal cord sections were obtained for microscopic examination.

RESULTS

In the control group immunized with S antigen, severe (2+ to 4+) uveoretinitis developed in 70% of the animals. In contrast, only 18% of the animals injected with NaIO3 at a dose of 50 mg/kg body weight exhibited disease, and this was a mild (1+) form. The groups injected with 25 mg/kg (1+ to 2+) and with 10 mg/kg (2+ to 3+) of NaIO3 showed a mild to moderate degree of uveoretinitis in 27% and 50% of the animals, respectively. In the remainder of the animals there was no evidence of uveoretinitis. All of the NaIO3-treated animals showed selective necrosis of the retinal pigment epithelium; this was extensive in the higher dose group and focal in the lower dose groups. In the experimental allergic encephalomyelitis model there was no significant difference in incidence or histologic appearance of demyelinating disease in NaIO3- vs diluent-treated groups.

CONCLUSIONS

These results indicate that the retinal pigment epithelium may play a role in the initiation and perpetuation of uveitis after sensitization with S antigen. The effect of NaIO3 appears to be localized to the retinal pigment epithelium; it had no effect on immune reactive cells, as evidenced by the development of experimental allergic encephalomyelitis in animals treated with NaIO3.

The blood-retinal barrier in experimental autoimmune uveoretinitis. Leukocyte interactions and functional damage

BACKGROUND

In posterior uveitis the blood-retinal barrier (BRB) plays an important role in the pathogenesis of the disease. However, the morphologic correlate of BRB breakdown and the route of leukocyte migration remain poorly defined.

EXPERIMENTAL DESIGN

Using an experimental model of autoimmune uveoretinitis in the rat, we have examined the ultrastructural alterations and leukocyte interactions occurring at the BRB. By employing electron-dense tracers, the development of BRB breakdown, and the route of extravasation were investigated.

RESULTS

No increase in BRB permeability was found before lymphocytic infiltration. At day 10 postimmunization with retinal-soluble antigen and beyond, inflammatory cells could be seen within the retina that was quickly followed by an extensive increase in the permeability of the retinal vasculature to lanthanum and horseradish peroxidase. Occasionally, horseradish peroxidase reaction product could be seen extending throughout the 'tight junctions' of the retinal endothelia, but not those of the retinal pigment epithelia. Inflammatory cells, particularly mononuclear cells, were seen forming perivascular cuffs and extending posteriorly towards the outer retina. Retinal damage was initially restricted to the outer nuclear and photoreceptor layers that were in close proximity to these vessels. Leukocytes could be seen adhering to the retinal vessels and penetrating the endothelial cell cytoplasm close to tight junctions, but were never seen probing the junctions directly. At the retinal pigment epithelium, however, there was little evidence of migration into the retina during the early stages of the disease, even though the choroid often became packed with inflammatory cells. At later stages, occasional inflammatory cells could be seen between, and apparently within, retinal pigment epithelium cells in areas overlying sites of severe choroidal infiltration.

CONCLUSIONS

The prime site of leukocyte infiltration and damage to the BRB in autoimmune uveoretinitis occurred at the level of the vascular endothelia and that diapedesis takes place primarily via an intraendothelial process.