Cellular immune response to retinal S-antigen and interphotoreceptor retinoid-binding protein fragments in Eales' disease patients

A compound heterozygous mutation in the S-Antigen Visual Arrestin SAG gene in a Chinese patient with Oguchi type one: a case report

Background

Oguchi disease is a rare autosomal recessive form of congenital quiescent night blindness. Oguchi disease has been found to be associated with gene mutations in SAG and GRK1, which are vital factors in the recovery phase of phototransduction after light stimuli. We report a case of Oguchi disease with novel heterozygous mutations in SAG.

Case presentation

A 7-year-old girl with a history of night blindness since childhood, was referred to our hospital. Ophthalmologic examinations included visual acuity, fundus examinations, fundus photography, spectral-domain optical coherence tomography, electroretinographic (ERG). Mutation screening of the SAG and GRK1 genes was performed. This patient exhibited typical clinical characteristics of Oguchi disease, including night blindness, golden fundus with the Mizuo–Nakamura phenomenon, packed structure of the parafovea in optical coherence tomography and reduced a-waves and b-waves in scotopic 3.0 ERG. Genetic testing revealed a heterozygous change in nucleotide c.72_75+15delATCGGTGAGTGGTGCACAA in exon 2 of the SAG gene in this patient, her unaffected mother and younger brother. A splicing alteration of nucleotide c.376-2A>C was identified in exon 6 of the SAG gene with heterozygous status in this patient and her unaffected father.

Conclusions

Compound heterozygosity of a nonsense p.S25X mutation in exon 2 and a splicing alteration in exon 6 of the SAG gene is the cause of this patient with Oguchi type 1 disease in China.

Eales' disease: epidemiology, diagnostic and therapeutic concepts

Background

To describe the epidemiological traits, clinical characteristics, diagnostic procedures, therapeutic interventions and evolution in a large series of patients with diagnosis of Eales’ disease.

Methods

A clinical retrospective review of patients with Eales’ disease, evaluated and treated between April 2009 and April 2018, with a 1-year minimum follow-up. Thirty patients (59 eyes), were included. Age, sex, laboratory results (CBC, glycemia, protein electrophoresis, ACE levels) immunological profile and a Quantiferon-TB Gold Plus test were recorded. The patients were divided into groups according to their evolution, medical or surgical treatment, and visual outcomes.

Results

Seventeen male patients and 13 female patients were included, and their ages ranged from 14 to 35 years. The Quantiferon-TB Gold Plus test was positive in 25 patients. Twenty-eight patients had unilateral vitreous hemorrhage, 10 of whom presented with vasculitis and non-perfusion areas in the contralateral eye, 9 presented contralateral peripheral neovascularization and 9 had contralateral fibrovascular proliferation. The remaining 2 patients presented with a rhegmatogenous retinal detachment. In 6 patients, conservative treatment with intravitreal anti-VEGF injections and photocoagulation was performed after the hemorrhage cleared. Twenty-two patients, required vitrectomy, with good visual outcomes. Macular edema was found in 16 eyes, which responded to periocular and/or systemic corticosteroid therapy, except for 9 eyes that required intravitreal bevacizumab, with complete resolution in 7 eyes and partial resolution in 2 eyes.

Conclusions

Eales’ disease is a pathology of significant prevalence in our country. The distribution according to sex, tends to be equivalent. The etiology, even when it is not specifically determined, according to laboratory tests, confirms the probable immunologic response in the presence of Mycobacterium tuberculosis antigens. This is still a diagnosis of exclusion, and therefore, it is advisable to perform a complete laboratory work-up in each case. Timely application of laser and other medical treatments, help to avoid progression to more advanced stages and their complications. The surgical treatment of vitrectomy for vitreous hemorrhage, and/or tractional vitreous detachment yields good primary anatomical and functional outcomes. Secondary macular edema responds to periocular and intravitreal corticosteroids, and in refractory cases, the use of anti-VEGF therapy leads to an effective resolution.

Diagnosis of Eales disease from a macular epiretinal membrane

Macular involvement is a common finding in patients with Eales disease. The purpose of this communication is to describe the diagnosis of Eales disease from the finding of a macular epiretinal membrane in a young patient. The case is presented of a 38-year-old man referred to this medical service unit with blurred vision developed over the past 3 months, and was associated with vitreoretinal traction and a macular epiretinal membrane. After an ophthalmological examination including the retinal periphery, optical coherence tomography, tuberculin test, interferon gamma release assay (IGRA), and a systemic study, the patient was diagnosed with Eales disease. Macular oedema or epiretinal membranes due to Eales disease are relatively common. Sd-OCT is recommended in all patients with Eales disease. On the other hand, the presence of epiretinal membranes in young patients usually suggests a non-idiopathic aetiology.

Spectral domain optical coherence tomography evaluation of macular changes in Eales disease

Purpose:

The purpose of the study was to describe macular changes in treatment-naïve eyes with Eales disease using spectral domain optical coherence tomography (SD-OCT).

Methods:

A cross-sectional study was done on 79 eyes of 66 patients with Eales disease. Best-corrected visual acuity (BCVA), slit-lamp biomicroscopy (SLB), indirect ophthalmoscopy, fundus fluorescein angiography (FFA), and quantitative (central macular thickness [CMT]) and qualitative analysis on SD-OCT were performed.

Results:

Forty-six (58.2%) eyes had macular involvement as assessed with SD-OCT, while in 33 (41.8%) eyes, macula was not affected. Macular edema was the most common feature when macula was affected followed by epiretinal membrane. Mean CMT was higher (315.3 ± 102.3 μm) in eyes with macular involvement than those without it (243.8 ± 19.3 μm). Eyes with active vasculitis involving larger vessels and neovascularization had greater chance of macular involvement. SLB and FFA alone missed 28.3% and 50% eyes with macular abnormalities on SD-OCT, respectively.

Conclusion:

While the clinical description of Eales disease points mainly to a peripheral location, macular involvement can be commonly picked up when SD-OCT is used. Macular involvement when present is associated with a poorer BCVA.

[Eales' disease]

The syndrome of recurrent vitreous hemorrhages in young men was described for the first time by Henry Eales in 1880. The association with a clinical manifestation of ocular inflammation was reported 5years later. Eales disease affects young adults who present with ischemic retinal vasculitis, with the peripheral retina most commonly affected. Most cases have been reported in South Asia. Although the etiology of this abnormality is unknown, it may be related to an immune sensitivity to Mycobacterium tuberculosis antigens. Its pathogenesis is related to extensive ischemia that affects the retina, secondary to an obliterative retinal vasculopathy with release of angiogenic factors of the VEGF type. Involvement of the retina is the hallmark of the disease, which manifests as follows: periphlebitis, retinal capillary ischemia most often affecting the periphery with secondary proliferative retinopathy and retinal and/or papillary neovascularization, recurrent vitreous hemorrhages and tractional retinal detachment. These complications are potentially blinding. The natural history of Eales disease varies, with temporary or permanent remission in some cases and continuous progression in others. Progression is often bilateral, which necessitates regular follow-up. The treatment of Eales disease depends on the stage of the disease and is not well defined. Observation only, pars plana vitrectomy surgery and/or intravitreal injections of anti-VEGF are recommended in cases of vitreous hemorrhage, associated with corticosteroids when retinal vasculitis is present. Laser pan-retinal photocoagulation is necessary when neovascularization is present.

Protein-ligand interaction studies of retinol-binding protein 3 with herbal molecules using AutoDock for the management of Eales' disease

Eales' disease is an idiopathic retinal vasculitis of the eye. The disease is predominantly characterized by recurrent vitreous hemorrhage. Interphotoreceptor retinol-binding protein 3 plays a significant role in the etiopathogenesis of this condition. It transports retinoids between the retinal pigment epithelium and the photoreceptors; hence, this protein is a potential target for docking studies. In silico data reveal that herbal molecules interact with regulatory domains of interphotoreceptor retinol-binding protein 3 (IRBP-3), resulting into significant docking score and also forms H-bond and several hydrophobic interactions between active residues of IRBP-3. These interactions between the active residues may lead to significant conformational change in that particular portion of the protein. This efficacy and suitability of ligand was determined on the basis of binding energy calculations. Ginkgolide showed minimum binding energy calculations among selected 10 other natural ligands. This fact of virtual screening for potential ligand can give new insights toward the therapeutic intonations and alterations toward the advances in treatment for Eales' disease.

Elevated tumor necrosis factor in serum is associated with increased retinal ischemia in proliferative eales' disease

OBJECTIVE

Tumor necrosis factor (TNF) was evaluated in the serum of patients with proliferative stage of Eales' disease to study its relation with the area of retinal capillary non-perfusion (ischemic retina).

METHODS

Quantification of the levels of TNF was done using sandwich ELISA in 52 cases with proliferative Eales' disease and in 32 healthy controls. Seven 50° photographs of different fields of the fundus were taken on fluorescein angiography. The area of retinal capillary non-perfusion denoting retinal cell death was assessed in terms of optic disc areas.

RESULTS

TNF levels were found to be significantly increased in the proliferative stage of the disease (mean 23.64 ± 3.7 pg/ml) as compared to controls (mean 12.49 ± 2.9 pg/ml; p < 0.001). Higher levels of TNF were found to be associated with an increased area of retinal capillary non-perfusion on fluorescein angiography. TNF levels of 20-31 pg/ml were observed in cases with neovascularization at the disc (n = 33) as compared to 17-21 pg/ml in cases with neovascularization elsewhere (n = 19).

CONCLUSIONS

An increased level of TNF is associated with an increased area of the ischemic retina. It is hypothesized that retinal cell death signaling in proliferative Eales' disease is related to an increased TNF level.

Comparative modeling of retinol-binding protein-3 and retinal S-antigen in Eales' disease and prediction of their binding sites using computational methods

Retinal S-antigen and interphotoreceptor retinoid-binding protein-3 play a significant role in the etiopathogenesis of Eales' disease. Protein 3D structures are functionally very important and play a significant role in progression of the disease, hence these 3D structures are better target for further drug designing and relative studies. We developed 3D model structure of retinol-binding protein-3 and retinal S-antigen protein of human involved in Eales' disease. Functional site prediction is a very important and related step; hence, in the current course of analysis, we predicted putative functional site residues in the target proteins. Molecular models of these proteins of Eales' disease as documented in this study may provide a valuable aid for designing an inhibitor or better ligand against Eales' disease and could play a significant role in drug design.

Antioxidant supplementation improves platelet membrane fluidity in idiopathic retinal periphlebitis (Eales' disease)

PURPOSE

Oxidative damage to cellular membranes plays an important role in the pathobiology of tissue injury. Retinal photoreceptors and platelets are an easy target of oxidants because of high proportion of polyunsaturated fatty acids. A tertiary-care center-based prospective study was undertaken to study the effect of antioxidant supplementation over membrane fluidity in platelets in idiopathic retinal periphlebitis (Eales' disease) for the first time.

METHODS

Assay of thiobarbituric acid reactive substances (TBARS) levels was done following a standard protocol and membrane fluidity in platelets was estimated using a fluorescent probe, 1,6-diphenyl-1,3,5-hexatrience, in 15 cases and 12 healthy controls. Prednisolone (1 mg/kg) in a weekly tapering dose for 6 weeks and a commercially available antioxidant preparation [lutein 3.2 mg (containing zeaxanthin 256 mcg), L-glutathione 5 mg, vitamin E 15 IU, vitamin C 150 mg, zinc 40 mg, copper 2 mg, selenium 40 mcg, and manganese 5 mg] was administered once a day for 3 months to all the cases. Pre- and postantioxidant supplementation platelet TBARS and membrane fluidity levels were assessed in all the cases.

RESULTS

Significant increase was observed in TBARS levels in the cases when compared with controls (P = 0.01). Platelet fluorescence polarization was significantly higher in cases, indicating decreased membrane fluidity, when compared with controls (P = 0.005). Antioxidant supplementation led to marked decrease in TBARS levels (P = 0.01) and improved levels of platelet membrane fluidity (P = 0.001).

CONCLUSION

Antioxidant supplementation leads to significant decrease in oxidative stress and a significant improvement in platelet membrane fluidity, thereby helping to prevent retinal photoreceptor dysfunction.

Tumor necrosis factor-α-mediated severity of idiopathic retinal periphlebitis in young adults (Eales' disease): implication for anti-TNF-α therapy

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic inflammatory cytokine. Tumor necrosis factor-alpha was evaluated in the serum samples of patients with idiopathic retinal periphlebitis in young adults (Eales' disease). Retinal periphlebitis was graded according to a new grading system based on severity of inflammation (grade 1-4). Quantification of the TNF-α levels was carried out using ELISA kit in the serum samples of young adults with idiopathic retinal periphlebitis (n = 17) and healthy controls (n = 17) of similar age. Tumor necrosis factor-α level was found to be significantly raised in cases with retinal periphlebitis as compared with controls (p < 0.001). Higher levels of TNF-α were found to be associated with increased severity of retinal periphlebitis. Tumor necrosis factor-α represents a novel target for controlling inflammatory activity in idiopathic retinal periphlebitis. Higher levels of TNF-α, in association with the increased severity of retinal periphlebitis, have implications for early anti-TNF-α therapy.

Interleukin-1 and tumor necrosis factor-alpha: novel targets for immunotherapy in Eales disease

BACKGROUND

Eales disease is an idiopathic obliterative vasculopathy that primarily affects the peripheral retina of young adults. The authors evaluated interleukin 1 beta (IL-1beta), interleukin-6 (IL-6), Interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-alpha) in the serum of patients with Eales disease stages for the first time.

METHODS

The study group consisted of 45 consecutive patients of Eales disease [inflammatory stage (n = 15) and proliferative stage (n = 30)] and 28 healthy controls. Immunoassays for the quantification of the levels of four cytokines including IL-1beta, IL-6, IL-10, and TNF-alpha in the serum samples were performed using ELISA kits.

RESULTS

IL-1beta, IL-6, IL-10, and TNF-alpha levels were found to be increased significantly in the inflammatory stage of Eales disease as compared to controls (p < .001). IL-1beta levels decreased significantly during the proliferative stage of the disease as compared to the inflammatory stage (p = .03). TNF-alpha levels increased significantly during the proliferative stage as compared to the inflammatory stage (p = .02).

CONCLUSIONS

Raised levels of IL-1beta and TNF-alpha were observed in the inflammatory stage and persisted in the proliferative stage of the disease. The IL-1 system and TNF-alpha represent novel target for immunotherapy for controlling inflammatory activity and/or the associated long-term sequelae related to angiogenesis in Eales disease.

Decreased platelet membrane fluidity in retinal periphlebitis in Eales' disease

PURPOSE

Oxidative damage to cellular membranes plays an important role in the pathobiology of tissue injury. Free radical-induced peroxidation of membrane lipid and protein is associated with alterations in cellular, morphological, biochemical, and physical dynamics, which are related to the mobility of lipid molecules. Retinal photoreceptors and platelets have been shown to be an easy target of oxidants because of their high proportion of polyunsaturated fatty acids. This study was undertaken, for the first time, to investigate membrane fluidity in the platelets of patients with Eales' disease.

METHODS

Assays of malonaldialdehyde levels and the enzymes superoxide dismutase and catalase and fluorescence polarization, for estimating membrane fluidity, were carried out on platelets from 20 patients with Eales' disease (stage 1 characterized by periphlebitis of small (1a) and large (1b) caliber vessels with superficial retinal hemorrhages) and 15 healthy controls.

RESULTS

A significant increase was observed in the malonaldialdehyde levels. A significant decrease in the activity of superoxide dismutase and catalase was also observed. Platelet fluorescence polarization was significantly higher in the patients, indicating decreased membrane fluidity compared to controls (p<0.01).

CONCLUSION

A decrease in platelet membrane fluidity occurs as a result of oxidative stress in retinal periphlebitis in Eales' disease. The decreased membrane fluidity suggests alterations in the physiological events, which may result in alterations in the functioning of retinal photoreceptors.

Treatment of neuro-ophthalmologic manifestations of tuberculosis

In the absence of obvious pulmonary or disseminated tuberculosis, ocular and central nervous system (CNS) tuberculosis may represent a significant diagnostic challenge. Refinements in polymerase chain reaction techniques and neuroimaging have strengthened the battery of tests used to diagnose CNS and ocular tuberculosis, yet in many cases, the diagnosis remains one of exclusion; it may ultimately be determined through exacerbation by anti-inflammatory therapy with subsequent improvement by antitubercular medication treatment. Because of emerging drug resistance, at least a two-drug regimen is required for therapeutic testing and treatment of isolated ocular tuberculosis. If pulmonary or miliary disease coexists, a 6-month, four-drug regimen with isoniazid, rifampin, pyrazinamide, and ethambutol is required for treatment. Tubercular meningitis is treated with the same four-drug regimen for at least 9 to 12 months. Burden of therapeutic compliance rests on the treating physician and public health sector. Best compliance is realized with directly observed therapy.

Response time and safety profile of pulsed oral methotrexate therapy in idiopathic retinal periphlebitis

PURPOSE

To evaluate the response time and safety profile of low-dose oral methotrexate pulsed therapy in idiopathic retinal periphlebitis (Eales' disease).

METHODS

A tertiary care center-based prospective interventional study, based on visual acuity grading, was undertaken. Twenty-one consecutive patients with idiopathic retinal periphlebitis were administered 12.5 mg methotrexate as a single oral dose, once per week for 12 weeks (cumulative dose = 150 mg). Each patient was assessed for change in visual acuity grades. Time of first therapeutic response was also noted. Drug safety was monitored by laboratory tests that included twice-weekly white blood cells and differential counts, twice-weekly platelet counts, and monthly liver function tests.

RESULTS

Twenty-one eyes were assessed. Mean follow-up period was 6 months. All showed improvement in visual acuity grades. An excellent visual outcome (6/6 or better) was achieved in 18 (69%) eyes. Time of first therapeutic response varied from 2 to 6 weeks with a majority of eyes (80%) showing response by 4 weeks (median = 3 weeks). All the side effects of methotrexate were mild or moderate in severity and rapidly reversible on dose reduction or discontinuation. No patient had any constitutional symptoms severe enough to necessitate cessation of therapy.

CONCLUSIONS

Low dose oral methotrexate pulse therapy (at a dose of 12.5 mg/week) is clinically effective within 4 weeks, and is associated with an acceptable safety profile.

A new staging system for idiopathic retinal periphlebitis

PURPOSE

To develop and standardize a universally acceptable new staging system for idiopathic retinal periphlebitis (Eales disease).

METHODS

A new staging system was established and standardized based on standard terminology and features. Idiopathic retinal periphlebitis was classified as peripheral and central types. Peripheral disease consisted of four stages. Stage 1 is periphlebitis of small (1a) and large (1b) caliber vessels with superficial retinal hemorrhages. Stage 2a denotes capillary nonperfusion and 2b neovascularization elsewhere/of the disc. Stage 3a is classified as fibrovascular proliferation and 3b vitreous hemorrhage. Stage 4a is traction/combined rhegmatogenous retinal detachment whereas 4b is rubeosis iridis, neovascular glaucoma, complicated cataract, and optic atrophy. A total of 253 cases of idiopathic retinal periphlebitis (mean age, 24.7 +/- 4.7 years, all male) presenting at this tertiary care center were classified prospectively according to the new staging system, by two independent observers (interobserver correlation = 0.7).

RESULTS

The new staging system was consistent, simple, and easy to recall. Peripheral and central types of idiopathic retinal periphlebitis were found in 94.07% and 5.93% of cases, respectively. The new staging system also defined the severity of the disease. Vitreous hemorrhage was found to be the commonest presenting feature (51.68%), whereas traction/combined rhegmatogenous detachment was found in 5.88% of cases.

CONCLUSIONS

The new staging system is useful in classifying and assessing the severity of disease. Management strategy can also be defined according to the stage of the disease. It is designed to promote the use of standard assessment with applications to clinical management and research.

The pathology and pathogenesis of retinal vasculitis

Retinal vasculitis is a rare, but potentially blinding intraocular inflammatory condition with diverse aetiology. Although commonly idiopathic, it has a strong association with systemic inflammatory diseases known to involve other areas of the central nervous system, most notably Behcet's disease, sarcoidosis, systemic lupus erythematosis and multiple sclerosis. This article describes the clinicopathologic features of retinal vasculitis and its visually damaging sequelae, reviewing available human histopathologic studies and work with experimental models to discuss the pathogenesis and immunopathology. Evidence indicates that noninfective retinal vasculitis is an autoimmune condition that may be induced by antecedent infection with microbes cross-reacting with putative autoantigens, influenced by genetic susceptibility of both HLA associations and cytokine polymorphisms. The growing understanding of the cellular mechanisms involved in the effector immune response is already providing a rationale for more specific therapeutic approaches.

Eales disease--an update

Eales disease, first described by Henry Eales in 1880, remains an enigma. The disease, observed more commonly in the Indian subcontinent than in the rest of the world, occurs in young healthy adult males, initially presenting as retinal periphlebitis and later as retinal ischemia that may lead to vascular alterations and neovascularization. Recurrent vitreous hemorrhage with or without retinal detachment is the common sequelae. In recent years, immunological, molecular biological, and biochemical studies have indicated the role of human leukocyte antigen, retinal autoimmunity, mycobacterium tuberculosis genome, and free radical mediated damage in the etiopathogenesis of this disease. However, its etiology appears to be multifactorial. The management depends on the stage of the disease and consists of medical treatment with oral corticosteroids in the active inflammatory stage and laser photocoagulation in the advanced retinal ischemia and neovascularization stages. The results of vitreoretinal surgery have been found to be satisfactory in case of vitreous hemorrhage with or without retinal detachment.