Herpes simplex virus type 1. A cause of the acute retinal necrosis syndrome

Long-term follow-up of acute retinal necrosis with retinal detachment secondary to herpes simplex virus type 2 with a successful visual outcome

A man in his early 20s presented with acute loss of vision in his only eye, the left eye (OS), and was on oral steroids. He had lost vision in his right eye during his childhood and the cause was unknown. There was no history of trauma. Best-corrected visual acuity (BCVA) in OS was 20/100 and in the right eye was hand movements. OS showed non-granulomatous keratic precipitates on the cornea, anterior chamber flare 1+ and cell 1+, early cataract, vitreous haze and cells 2+ with nasal retinal detachment and superior full thickness retinitis. He underwent pars plana vitrectomy with intravitreal ganciclovir and barrage laser away from the necrotic retina. PCR for herpes simplex virus 2 was positive from the aqueous and vitreous sample. He was started on oral valacyclovir 1 g three times a day and continued on tapering dose of oral steroids. BCVA in OS at 6-month follow-up was 20/25.

Programmed Cell Death-Dependent Host Defense in Ocular Herpes Simplex Virus Infection

Herpes simplex virus type 1 (HSV1) remains one of the most ubiquitous human pathogens on earth. The classical presentation of HSV1 infection occurs as a recurrent lesions of the oral mucosa commonly refer to as the common cold sore. However, HSV1 also is responsible for a range of ocular diseases in immunocompetent persons that are of medical importance, causing vision loss that may result in blindness. These include a recurrent corneal disease, herpes stromal keratitis, and a retinal disease, acute retinal necrosis, for which clinically relevant animal models exist. Diverse host immune mechanisms mediate control over herpesviruses, sustaining lifelong latency in neurons. Programmed cell death (PCD) pathways including apoptosis, necroptosis, and pyroptosis serve as an innate immune mechanism that eliminates virus-infected cells and regulates infection-associated inflammation during virus invasion. These different types of cell death operate under distinct regulatory mechanisms but all server to curtail virus infection. Herpesviruses, including HSV1, have evolved numerous cell death evasion strategies that restrict the hosts ability to control PCD to subvert clearance of infection and modulate inflammation. In this review, we discuss the key studies that have contributed to our current knowledge of cell death pathways manipulated by HSV1 and relate the contributions of cell death to infection and potential ocular disease outcomes.

Classification Criteria for Acute Retinal Necrosis Syndrome

PURPOSE

To determine classification criteria for acute retinal necrosis (ARN).

DESIGN

Machine learning of cases with ARN and 4 other infectious posterior uveitides / panuveitides.

METHODS

Cases of infectious posterior uveitides / panuveitides were collected in an informatics-designed preliminary database, and a final database was constructed of cases achieving supermajority agreement on diagnosis, using formal consensus techniques. Cases were split into a training set and a validation set. Machine learning using multinomial logistic regression was used on the training set to determine a parsimonious set of criteria that minimized the misclassification rate among the infectious posterior uveitides / panuveitides. The resulting criteria were evaluated on the validation set.

RESULTS

Eight hundred three cases of infectious posterior uveitides / panuveitides, including 186 cases of ARN, were evaluated by machine learning. Key criteria for ARN included (1) peripheral necrotizing retinitis and either (2) polymerase chain reaction assay of an intraocular fluid specimen positive for either herpes simplex virus or varicella zoster virus or (3) a characteristic clinical appearance with circumferential or confluent retinitis, retinal vascular sheathing and/or occlusion, and more than minimal vitritis. Overall accuracy for infectious posterior uveitides / panuveitides was 92.1% in the training set and 93.3% (95% confidence interval 88.2, 96.3) in the validation set. The misclassification rates for ARN were 15% in the training set and 11.5% in the validation set.

CONCLUSIONS

The criteria for ARN had a reasonably low misclassification rate and seemed to perform sufficiently well for use in clinical and translational research.

Clinical course of von Szily reaction: Case report and comprehensive review of the literature

Purpose

To describe a rare case of von Szily reaction (VSR) accompanied by a comprehensive review of the literature.

Observations

A 57-year-old woman with herpes zoster ophthalmicus (HZO) associated with ipsilateral sectoral scleritis and anterior uveitis (sclerouveitis) subsequently developed contralateral necrotizing retinitis, leading to a diagnosis of VSR. A literature review revealed 10 additional cases of VSR. The full VSR cohort of 11 subjects included six women and five men, had a median age of 39 years (range 21–78 years), and most presented with HZO (n = 7, 63.6%), often associated with either ipsilateral anterior uveitis (n = 5; 45.5%) or keratitis (n = 4; 36.4%). All 11 cases developed necrotizing retinitis in the fellow eye, at a median of six weeks following onset in the sentinel eye. The most frequently implicated agent was varicella zoster virus (VZV; n = 8, 72.7%). A high proportion of the eight patients with VZV-associated VSR were identified as having increased risk of VZV reactivation, including age of 50 years or greater (n = 5, 62.5%), an underlying malignancy (n = 3, 37.5%), and/or use of immunosuppressive medication (n = 2, 25.0%).

Conclusion

This was the first reported case of VSR presenting as HZO-associated with sclerouveitis. A comprehensive literature review revealed that most previously reported cases presented with HZO associated with isolated anterior uveitis and/or keratitis, and that all reported cases of VSR developed necrotizing retinitis in the fellow eye, typically within two months of initial presentation. Patients with VZV-associated VSR often had known risk factors for VZV reactivation.

Acute retinal necrosis: Clinical manifestation and long-term visual outcomes in a series of polymerase chain reaction-positive patients

PURPOSE

To report the clinical spectrum, viral etiologies, therapeutic interventions, timing of rhegmatogenous retinal detachments (RRD), and visual outcomes in acute retinal necrosis (ARN) syndrome in a series of polymerase chain reaction (PCR)-positive eyes.

METHODS

From January 2010 to January 2017, consecutive patients with the clinical diagnosis of ARN and a positive aqueous viral PCR were included in this observational, retrospective study.

RESULTS

Nineteen eyes found to have a clinical diagnosis of ARN, of which 18 (94.7%) had a positive viral PCR. ARN was unilateral, except in one patient. None of the fellow eyes manifested ARN during follow-up. Varicella-zoster virus (VZV) was detected in 78.0% of ARN eyes. 61.1% of eyes experienced RRD. The median time for the occurrence of RRD was 12 weeks (range: 6-25 weeks) after disease onset. No correlation was found between the etiologic viral agent (VZV vs non-VZV; p = 1.000), extent of retinitis (1-2 quadrant vs 3-4 quadrants; p = 0.326), administration of intravitreal ganciclovir (injected vs not injected; p = 0.332), application of prophylactic laser retinopexy (applied vs not applied; p = 0.326), and subsequent occurrence of RRD.At a 2-year follow-up, visual impairment (VA ⩽ 20/200) and severe visual loss (VA ⩽ light perception) were significantly higher in those complicated by RRD compared to non-RRD eyes (81.8% vs 28.6%; p = 0.047, and 45.4% vs 0.0%; p = 0.004, respectively).

CONCLUSION

Aqueous PCR results are highly consistent with the clinical diagnosis of ARN. Regardless of the method of management, the rate of RRD is high and is associated with a poor visual outcome.

Zika Virus Infection in the Developing Mouse Produces Dramatically Different Neuropathology Dependent on Viral Strain

Zika virus (ZIKV) infection during pregnancy has been causally linked to a constellation of neurodevelopmental deformities in the fetus resulting in a disease termed congenital Zika syndrome (CZS). Here we detail how ZIKV infection produces extensive neuropathology in the developing mouse brain and spinal cord of both sexes. Surprisingly, neuropathology differs depending on viral strain with a French Polynesian isolate producing primarily excitotoxicity and a Brazilian isolate being almost exclusively apoptotic but occurring over a prolonged period that is more likely to produce severe hypoplasia. We also show exposure can produce a characteristic pattern of infection that mirrors neuropathology and ultimately results in gross morphological deformities strikingly similar to CZS. This research provides a valuable mouse model mirroring the clinical course of disease that can be used to test potential therapies to improve treatment and gain a better understanding of the disabilities associated with CZS.SIGNIFICANCE STATEMENT Zika virus (ZIKV) infection during pregnancy has been causally linked to a constellation of neurodevelopmental deformities in the fetus resulting in a disease termed congenital Zika syndrome. Despite its devastating effects, very little is known about how ZIKV infection produces fetal neuropathology. Here we detail the temporal progression of ZIKV infection in the mouse brain and spinal cord resulting in massive neurodegeneration of infected regions. We also report a ZIKV strain from a region of Brazil with high levels of microcephaly (abnormally small head circumference) produces particularly devastating neuropathology.

Clinical feature and visual prognosis of acute retinal necrosis according to the initially involved zone and extent: 10-year experience

Purpose:

We aimed to analyze the visual prognosis and clinical characteristics of acute retinal necrosis according to the initially involved zone and extent.

Study design:

Retrospective, consecutive, cross-sectional study.

Methods:

We retrospectively reviewed acute retinal necrosis patients who were treated with systemic antiviral treatment, and assessed the visual prognosis of acute retinal necrosis following antiviral treatment based on the initially involved zone and the extent of acute retinal necrosis at the time of diagnosis. Moreover, we evaluated whether prophylactic laser photocoagulation had preventive effects on retinal detachment.

Results:

A total of 43 eyes from 35 patients with acute retinal necrosis were included. Eyes with zone I involvement/extensive retinal lesions showed poor visual prognosis (logMAR: 1.17 ± 0.97 vs 0.49 ± 0.81; p = 0.014) and a higher incidence of retinal detachment (9/30 (30.0%) vs 0/13 (0%); p = 0.039) after treatment. Retinal detachment was observed in 20.9% of cases, and its incidence was significantly lower in eyes that had undergone prophylactic laser photocoagulation.

Conclusion:

The overall visual prognosis of acute retinal necrosis is poor and can be determined at the time of diagnosis. Prophylactic laser photocoagulation exhibits preventive effects with regard to the development of retinal detachment. Therefore, laser photocoagulation should be actively considered in eyes with extensive retinal lesions to prevent retinal detachment and thus eventually improve the overall visual prognosis of acute retinal necrosis.

Atypical acute retinal necrosis accompanied by Terson's syndrome: a case report

Background

Acute retinal necrosis (ARN) has characterized by panuveitis, vitritis, severe vaso-occlusive vasculitis, and diffuse necrotizing retinitis. There are no case reports on atypical ARN combined with Terson’s syndrome. Herein, we report a case of ARN with atypical clinical features combined with Terson’s syndrome that we successfully treated by intravitreal ganciclovir injection.

Case presentation

A 64-year-old man visited our eye clinic with a complaint of decreased visual acuity in his right eye. At the initial visit, his best corrected visual acuity was 20/125 in the right eye. Slit-lamp examination demonstrated mild hyperemia, keratic precipitates, and anterior chamber inflammatory reaction. Fundus examination revealed multiple diffuse white-yellowish infiltrations in the peripheral retina combined with dot hemorrhages. Ultra-wide-field fluorescence angiography showed obstructive arteritis with peripheral non-perfusion and leakage from the retinal vessels. As a result of the PCR analysis, varicella zoster virus DNA was identified in the aqueous humor. Under the diagnosis with VZV-mediated ARN, we started with intravenous acyclovir and oral prednisolone. After 3 days of the above treatment, the anterior chamber inflammation and vitreous opacity were increased. On fundus examination, multiple whitish infiltrations were increased. In addition, newly developed vitreous and peripapillary hemorrhages were detected. On the T2 brain magnetic resonance imaging (MRI) demonstrated a sub-acute or old hemorrhagic infarction in the right occipital lobe, and contrast-enhancing lesions in the right basal ganglia. The spinal tapping was performed in the department of neurology in our hospital at the time when the patient complained of headache, and intracranial pressure was 31 mmHg. Under the diagnosis of ARN with Terson’s syndrome, we started intravitreal ganciclovir (2 mg/0.5 ml) injections. After 5 intravitreal ganciclovir injections over a period of 8 months, the diffuse whitish infiltrating retinal lesions combined with dot hemorrhage were decreased. The vitreous and peripapillary hemorrhage was significantly reduced. There was no recurrence in the patient’s right eye, in which his visual acuity had improved to 20/60.

Conclusions

In the event of a poor response to traditional treatment such as intravenous acyclovir, intravitreal ganciclovir may have a role as an adjunctive therapy in patients of VZV associated ARN combined with Terson’s syndrome.

Intraocular Detection of Herpes viruses by xTAG Liquid Chip Technology in Patients with Acute Retinal Necrosis

PURPOSE

To evaluate the performance of the xTAG liquid chip technology (xTAG-LCT) for etiological diagnosis of acute retinal necrosis (ARN).

METHODS

Fifteen vitreous and 3 aqueous samples from 18 ARN patients were analyzed by xTAG-LCT and multiplex PCR (mPCR)/quantitative PCR (qPCR).

RESULTS

xTAG-LCT revealed positive results in 17 of the 18 samples: 10 for Varicella Zoster Virus (VZV) alone; 5 for VZV and Epstein-Barr virus (EBV); 1 for herpes simplex viruses type 1 (HSV-1) and EBV; 1 for VZV, HSV-1 and EBV. While mPCR revealed the same results as xTAG-LCT for VZV and HSV-1 in all samples, only 2 of the 7 samples positive for EBV on xTAG-LCT were confirmed by qPCR. None of the 28 control vitreous samples from 8 non-ARN patients and 10 pair of cadaveric eyes was positive for any of the tested viruses.

CONCLUSIONS

xTAG-LCT could be a useful alternative for etiological diagnosis of ARN.

A systematic approach to emergencies in uveitis

Uveitis is a common cause of preventable blindness although it is consider a sight-threatening condition particularly in cases with posterior segment inflammation. To deal with emergency conditions in uveitis, we must aware of the essential signs and symptoms that reflect a true uveitic emergency. Failure to recognize these essential signs and symptoms of a true uveitic emergency may result in a devastating visual outcome. This review provides general ophthalmologists and residents, clinical guidelines for the main uveitic entities that require immediate recognition and urgent intervention in the emergency room to prevent severe permanent visual loss.

Acute retinal necrosis: factors associated with anatomic and visual outcomes

PURPOSE

To examine the factors associated with anatomic and visual outcomes in Japanese patients with acute retinal necrosis (ARN).

METHODS

One hundred four patients with ARN who were followed for more than 1 year at nine referral centers were reviewed. Retinal involvement at initial presentation was classified into four groups: zone 1 (posterior pole, n = 22), zone 2 (midperiphery, n = 54), zone 3 (periphery, n = 25), and unknown (n = 3). Forty-eight eyes underwent prophylactic vitrectomy before development of retinal detachment (vitrectomy group); 56 eyes were treated conventionally without prophylactic vitrectomy (observation group).

RESULTS

The retina was attached in 28 of 48 eyes (58.3 %) in the vitrectomy group and 42 of 56 eyes (75.0 %) in the observation group at the final visit (P = 0.071). At 1 year, 56 eyes (53.8 %) had a best-corrected visual acuity (BCVA) of 20/200 or worse. Multivariate logistic regression analyses identified zone 1 disease (odds ratio = 4.983) and optic nerve involvement (odds ratio = 5.084) as significantly associated with BCVA of 20/200 or worse. Among the zone 3 eyes, significantly (P = 0.012) more eyes in the observation group than in the vitrectomy group had an attached retina.

CONCLUSIONS

Prophylactic vitrectomy did not improve the final BCVA in any eyes. Zone 3 eyes had better outcomes without prophylactic vitrectomy.

Polymerase chain reaction for diagnosis of herpetic intraocular inflammation

The authors present a polymerase chain reaction method for rapid and direct diagnosis of herpetic intraocular infections using small volume samples of intraocular fluid from 29 patients with various intraocular inflammatory diseases and 24 controls with senile cataract. Of six patients with early acute retinal necrosis from whom aqueous humor was tested, four were found to be positive for the presence of varicella-zoster (VZV) DNA while the other two were positive for the presence of herpes simplex virus (HSV) DNA. One of the patients with HSV DNA had been tested at an extremely early stage, at which time the aqueous humor viral antibody ratio did not predict a specific viral infection. Among four patients with acute retinal necrosis in relatively late stages following treatment with acyclovir from whom vitreous was obtained and tested, only one was found to have the presence of any viral DNA (VZV). On the other hand, the vitreous viral antibody ratio was found to be predictive of VZV infection in all four cases. VZV DNA was also detected in aqueous humor samples from four patients with suspected herpes zoster anterior uveitis, while HSV DNA was found in the aqueous humor of one patient with nonspecific keratouveitis. Neither human cytomegalovirus DNA nor human herpesvirus-6 DNA was detected in any sample included in this study. Finally, Epstein-Barr virus DNA was detected in the aqueous humor of the majority of patients studied and identified in cataract patients as well, suggesting either low specificity of the authors' assay for this virus or ubiquity of this virus in human eyes. In summary, the PCR method proved to be a very useful tool in establishing an etiological diagnosis in patients in the early stages of acute retinal necrosis, and in patients with anterior uveitis due to suspected HSV or VZV infection.

Acute retinal necrosis after Boston type I keratoprosthesis

A case report of a 68-year-old male who developed acute retinal necrosis (ARN) after Boston type I keratoprosthesis is presented. The procedure was performed for multiple graft failure secondary to herpetic keratitis. Clinical data including visual acuity, color fundus photography, fluorescein angiography, laboratory tests findings, and management are presented. After exclusion of other causes by laboratory workup, the patient was diagnosed with ARN most likely secondary to herpetic infection. Intravenous acyclovir and oral prednisolone were administered to the patient resulting in marked improvement in visual acuity and regression in the size of the retinitis. The patient eventually developed a soft eye and choroidal detachment with light perception vision. In patients with a history of herpetic keratitis or keratouveitis, it is highly advisable to maintain prophylactic systemic antiviral treatment before and after any ocular procedure such as the Boston keratoprosthesis.

Acute retinal necrosis associated optic neuropathy

Acute retinal necrosis (ARN) syndrome is characterized by severe intraocular inflammation, occlusive vasculopathy and peripheral retinal necrosis. Vision threatening complications of this syndrome include retinal detachment, macular oedema and ischaemia and optic neuropathy. Optic nerve involvement may be the presenting sign of ARN and this condition should be included in the differential diagnosis of acute papillitis. Several mechanisms may lead to ARN associated optic neuropathy including vasculitis, optic nerve ischaemia and direct optic nerve invasion by the herpes virus. We review optic nerve involvement during ARN and present its incidence, pathogenesis, differential diagnosis and treatment.

Kyrieleis plaques associated with acute retinal necrosis from herpes simplex virus type 2

PURPOSE

To present the case of a 19-year-old woman with acute retinal necrosis syndrome due to herpes simplex virus type 2, who developed segmental periarterial (Kyrieleis) plaques six and one half weeks into her clinical course.

METHODS

Retrospective case report.

PATIENTS

Single patient with the diagnosis of acute retinal necrosis syndrome.

RESULTS

The patient's vitreous biopsy was positive by polymerase chain reaction for herpes simplex virus type 2.

DISCUSSION

Kyrieleis plaques have been found in the setting of toxoplasmosis, tuberculosis, syphilis, rickettsial disease, herpes zoster virus, intraocular lymphoma, and idiopathic branch retinal artery occlusions. The differential diagnosis for these periarterial plaques should also include herpes simplex virus type 2.

Long-term follow-up of acute retinal necrosis

PURPOSE

The purpose of this study was to report long-term visual outcome of acute retinal necrosis.

METHODS

Medical records of patients with acute retinal necrosis were reviewed.

RESULTS

Thirty-two patients were diagnosed with acute retinal necrosis from 1998 to 2007. Twenty patients (25 eyes) had at least 1 follow-up and available medical records. Intravitreal injections of ganciclovir and/or foscarnet were administered in 11 of 25 eyes. Intravenous and oral antiviral medications were used in 14 of 20 and 19 of 20 patients, respectively. Eleven of 25 eyes had <25% of retina affected, 8 of 25 had 25% to 50% of retina affected, and 6 of 25 had >50% of retina affected. Mean visual acuity at all time points was best when retinitis involved <25% and decreased as area increased. All but 1 eye with >50% involvement experienced decreased vision regardless of treatment. Three of 4 eyes with 25% to 50% involvement that received intravitreal antivirals had an improvement in visual acuity of > or =2 Snellen lines. Five of 25 eyes developed retinal detachment. None of the six eyes treated with prophylactic laser detached.

CONCLUSION

Greater extent of retinitis portends a worse visual prognosis. Although intravitreal treatment did not prevent visual acuity loss in patients with severe disease, patients with moderate disease (25-50% retina involved) did well with intravitreal therapy with most having stable or improved visual acuity. Prophylactic laser decreased the rate of detachment.

[Acute retinal necrosis: Clinical features and therapy options]

Varicella zoster virus is the most frequent cause of acute retinal necrosis (ARN) followed by herpes simplex virus. Retinal ischemia and optic nerve atrophy are the main causes of the frequently poor final visual outcome in severe cases of ARN. The clinical diagnosis of ARN should be made as early as possible. Acyclovir should be administered intravenously due to its unreliable oral bioavailability. Systemic corticosteroids should be applied to suppress tissue damage caused by the host's inflammatory response. Severe cases of ARN should be treated by early vitrectomy with diagnostic vitreous biopsy, intravitreal aciclovir lavage, intraoperative laser retinopexy and silicone oil tamponade. The role of prophylactic laser retinopexy for prevention of secondary retinal detachment remains to be determined. The cause of different degrees of severity of ARN is unknown. The degree of severity of ARN is probably an independent predictor of the functional outcome.

Role of nectin-1, HVEM, and PILR-alpha in HSV-2 entry into human retinal pigment epithelial cells

PURPOSE

Herpes simplex virus-type 2 (HSV-2) can cause acute retinal necrosis (ARN), which can lead to exudative and rhegmatogenous retinal detachment, yet little is known about the cellular and molecular mechanisms of HSV-2 entry into retinal pigment epithelial (RPE) cells. The goal of this study was to establish the identity of the critical receptors used by the virus for infection.

METHODS

A reporter HSV-2 virus, which expresses beta-galactosidase, was used to quantify entry into RPE cells, and viral replication was ascertained using a plaque assay. Flow cytometry and immunocytochemistry were used to determine cellular expression of entry receptors. Localization of these receptors to the apical or basal surface of RPE cells was determined with immunocytochemistry. The necessity of these receptors, individually and in combination, for viral entry was established using receptor-specific antibodies and siRNAs.

RESULTS

RPE cells are highly susceptible to HSV-2 entry and replication. Several assays demonstrated the expression of the entry receptors nectin-1, HVEM, and PILR-alpha and their localization primarily to the apical surfaces of RPE cells. Receptor-specific antibodies and siRNA knockdown of receptors significantly reduced viral entry and implicated nectin-1 as an important receptor, with HVEM and PILR-alpha potentially also contributing to entry.

CONCLUSIONS

HSV-2 is capable of developing a productive infection in RPE cells by using nectin-1 as an important entry receptor. To lesser degrees, HVEM and PILR-alpha may also contribute to HSV-2 entry into RPE cells.

Acute retinal necrosis in primary herpes simplex virus type I infection

Here we report the case of an immunocompetent 8-year-old child who developed acute retinal necrosis concomitant with a primary herpes simplex virus type I infection. Ocular inflammation changed along with the development of a specific antibody titer in the serum. This evidence suggests that the immune response of the host can significantly modulate the clinical aspect of the ocular infection.

Neutrophils protect the retina of the injected eye from infection after anterior chamber inoculation of HSV-1 in BALB/c mice

PURPOSE

To determine whether infiltrating polymorphonuclear leukocytes PMNs play a role in preventing early direct anterior-to-posterior spread of herpes simplex virus (HSV)-1 and/or in preventing the spread of HSV-1 from the brain back to the retina of the injected eye after anterior chamber (AC) inoculation.

METHODS

BALB/c mice were treated with monoclonal antibody RB6-8C5 (Gr-1) against PMNs or control IgG and inoculated with HSV-1.

RESULTS

In Gr-1-treated mice, PMNs were depleted in the peripheral blood and in the HSV-1-infected eye. More virus (2-3 logs) was recovered from the inoculated eye of Gr-1 antibody-treated mice than from control mice. Immunohistochemistry revealed disseminated virus-infected cells in the junction between the anterior and the posterior segment and also in the posterior segment of the HSV-1-inoculated eye in Gr-1-treated mice. In control IgG-treated mice, virus-infected cells were observed only within the AC. More virus (3 logs) was recovered from the contralateral suprachiasmatic nucleus (SCN), and increased virus staining was observed in the ipsilateral optic nerve of Gr-1-treated mice compared with control mice. In Gr-1-treated mice, the central retina was virus-infected in a patchy fashion beginning on day 7 post infection (pi), and the infection progressed to involve the entire retina.

CONCLUSIONS

Since both direct anterior-to-posterior spread of virus and spread via the optic nerve occurred in PMN-depleted mice, these results suggest that PMNs play an important role both in limiting intraocular spread of virus in the injected eye and in controlling spread of the virus from the brain into the optic nerve and retina of the injected eye.

Uniocular anterior chamber inoculation of a tumor necrosis factor alpha-expressing recombinant of herpes simplex virus type 1 results in more rapid destruction and increased viral replication in the retina of the uninoculated eye

Tumor necrosis factor alpha (TNF-alpha) has been shown to have a protective role in the eyes and brains of herpes simplex virus type 1 (HSV-1)-infected mice. To determine whether overexpression of TNF-alpha affected the course of virus infection following uniocular anterior chamber inoculation, a recombinant of HSV-1 that produces TNF-alpha constitutively (KOSTNF) was constructed. BALB/c mice were injected with the TNF-alpha recombinant, a recombinant containing the pCI plasmid, a recombinant rescue virus, or the parental virus. Flow cytometry and immunohistochemistry were used to identify virus-infected cells and to determine the numbers and types of infiltrating inflammatory cells in the uninjected eyes. Virus titers were determined by plaque assay. There were no differences among the groups in virus titers or the route and timing of virus spread in the injected eyes or in the suprachiasmatic nuclei. However, in the uninjected eyes of KOSTNF-infected mice, TNF-alpha expression was increased and there were more viral antigen-positive cells and immune inflammatory cells. There was earlier microscopic evidence of retinal infection and destruction in these mice, and the titers of virus in the uninjected eyes were significantly increased in KOSTNF-infected mice on day 7 postinfection compared with those of KOSpCI-, KOS6beta rescue-, or KOS6beta-infected mice. The results suggest that instead of moderating infection and reducing virus spread, overexpression of TNF-alpha has deleterious effects due to increased inflammation and virus infection that result in earlier destruction of the retina of the uninoculated eye.

Two patients with the von Szily reaction: herpetic keratitis and contralateral retinal necrosis

PURPOSE

To present two patients with prior unilateral, herpetic keratitis who developed acute retinal necrosis (ARN) in the contralateral eye. These cases have noticeable similarities to the von Szily reaction. This describes the development of a contralateral retinitis subsequent to an anterior chamber injection of herpes simplex virus (HSV).

DESIGN

Interventional case series.

METHODS

Retrospective chart and literature review.

RESULTS

The first patient had neonatally acquired herpetic keratitis and developed ARN at age 21. Polymerase chain reaction of a vitreous biopsy detected HSV type-2 (HSV-2). The second patient was clinically diagnosed with ARN contralateral to varicella zoster keratitis. A detailed literature search located seven prior case reports with a von Szily reaction. These resembled our two cases except none had HSV-2 or years of latency from keratitis to retinitis.

CONCLUSIONS

Clinicians need to be cognizant of the von Szily reaction.

Detection of herpes simplex virus type 1 DNA in bilateral human trigeminal ganglia and optic nerves by polymerase chain reaction

Herpes simplex virus type 1 (HSV-1) DNA was extracted from human trigeminal ganglia of 121 cadavers aged between 3 months and 94 years, and its PCR amplification was performed for the RL2 HSV-1 sequence using two pairs of primers. The HSV-1 DNA was detected in 74 of 121 patients (61%); 70/74 bilaterally, 3/74 only on the left side, and 1/74 only on the right side. Although the PCR-positive rate was significantly higher in advanced age, the correlation between the PCR-positive rate and gender was unclear. Additionally, HSV-1 DNA was not detected in any of the 50 optic nerve samples.

Acute retinal necrosis features, management, and outcomes

OBJECTIVE

To determine the viral diagnosis and factors affecting the visual outcome of eyes with acute retinal necrosis.

DESIGN

Nonrandomized, retrospective, interventional, noncomparative series.

PARTICIPANTS

A cohort of 22 human immunodeficiency virus-negative patients with acute retinal necrosis (ARN). There were 17 unilateral and 5 bilateral cases.

INTERVENTION

Diagnostic vitreous biopsy for polymerase chain reaction (PCR) viral DNA analysis, prophylactic barrier laser posterior to necrotic retina to try to prevent rhegmatogenous retinal detachment (RD), intravenous acyclovir in combination with oral, and vitrectomy for RD repair.

MAIN OUTCOME MEASURES

Results of PCR viral DNA analysis, relationship between prophylactic barrier argon laser photocoagulation and occurrence of RD, and visual acuities at presentation and follow-up.

RESULTS

Varicella-zoster virus (VZV) was detected in 66.7% (12/18) of eyes (66.7% of patients [10/15]) with vitreous biopsy and herpes simplex virus (HSV) in 22.2% (4/18) of eyes (20% of patients [3/15]). Epstein-Barr virus (EBV) was detected in 16.7% (3/18) of eyes (20% of patients [3/15]), and all the EBV-positive eyes were also positive for VZV. Polymerase chain reaction results were identical in both eyes of bilateral cases (5 patients) and were negative in 11.1% (2/18) of eyes (13.3% of patients [2/15]) biopsied. Systemic corticosteroid treatment given before ARN diagnosis did not appear to increase the risk of developing RD (P = 0.69). Rhegmatogenous RD occurred in 35.3% (6/17) of eyes given prophylactic argon laser treatment and in 80% (8/10) of eyes that could not be lasered prohylactically. Of RDs, 96.3% (13/14) occurred after the third week and up to 5 months from onset of symptoms. The VA after surgical repair of RD improved relative to the presentation acuity in 33.3% (4/12) of eyes.

CONCLUSION

Varicella-zoster virus is the leading cause of ARN. We recommend the management of ARN to include prompt diagnosis; prophylactic argon laser retinopexy, preferably within the first 2 weeks to reduce risk of RD; systemic acyclovir; and corticosteroids to control the severe inflammation associated with ARN. Despite the guarded visual prognosis, RD repair may result in improved visual outcomes.

Analysis of retinal findings of acute retinal necrosis using optical coherence tomography

PURPOSE

To analyze the retinal findings in patients with ARN, optical coherence tomography (OCT) was performed.

METHODS

Seven patients (7 eyes) with ARN were studied using OCT.

RESULTS

OCT images depicted highly reflective areas in the inner layers of the retina in all seven cases, corresponding with the yellowish-white lesions of the retina in the acute phase. Disorganization of the retinal structure was also observed in these retinal lesions, especially in cases with severe inflammation. Subretinal changes including retinal exudate and/or fluid were observed in only one case. After regression of the yellowish-white lesions in the retina, a significant reduction in retinal thickness was observed on OCT.

CONCLUSIONS

OCT permits the detection of full-thickness retinal necrosis in the acute phase and complete absence of retinal structure in the resolution phase, corresponding with the yellowish-white lesions seen in patients with ARN.

HIV-associated retinopathy in the HAART era

BACKGROUND

The effectiveness of highly active antiretroviral therapy (HAART) in restoring immune function in patients with acquired immunodeficiency syndrome (AIDS) has led to changes in the incidence, natural history, management, and sequelae of human immunodeficiency virus (HIV)-associated retinopathies, especially cytomegalovirus (CMV) retinitis.

METHODS

The medical literature pertaining to HIV-associated retinopathies was reviewed with special attention to the differences in incidence, management strategies, and complications of these conditions in the eras both before and after the widespread use of HAART.

RESULTS

In the pre-HAART era, CMV retinitis was the most common HIV-associated retinopathy, occurring in 20%-40% of patients. Median time to progression was 47 to 104 days, mean survival after diagnosis was 6 to 10 months, and indefinite intravenous maintenance therapy was mandatory. Retinal detachment occurred in 24%-50% of patients annually. Herpetic retinopathy and toxoplasmosis retinochoroiditis occurred in 1%-3% of patients and Pneumocystis carinii choroiditis, syphilitic retinitis, tuberculous choroiditis, cryptococcal choroiditis, and intraocular lymphoma occurred infrequently. In the HAART era the incidence of CMV retinitis has declined 80% and survival after diagnosis has increased to over 1 year. Immune recovery in patients on HAART has allowed safe discontinuation of maintenance therapy in patients with regressed CMV retinitis and other HIV-associated retinopathies. Immune recovery uveitis (IRU) is a HAART dependent inflammatory response that may occur in up to 63% of patients with regressed CMV retinitis and elevated CD4 counts and is associated with vision loss from epiretinal membrane, cataract, and cystoid macular edema.

CONCLUSIONS

The incidence, visual morbidity, and mortality of CMV retinitis and other HIV-associated retinopathies have decreased in the era of HAART and lifelong maintenance therapy may safely be discontinued in patients with restored immune function. Patients with regressed CMV retinitis, however, may still lose vision from epiretinal membrane, cystoid macular edema, and cataract secondary to IRU.

Herpes simplex virus type 1 encephalitis associated with acute retinal necrosis syndrome in an immunocompetent patient

PURPOSE

The onset of acute retinal necrosis secondary to herpes simplex encephalitis is exceptional. We report such an association in an immunocompetent patient, in whom the genome of herpes simplex virus type 1 (HSV-1) was identified successively at both sites of infection.

METHODS

Polymerase chain reaction (PCR) assay of HSV-1 in cerebrospinal fluid (CSF) and aqueous humour.

RESULTS

An immunocompetent patient aged 40 years presented with HSV-1 encephalitis, which was confirmed by imaging, viral serology and identification of the HSV-1 genome in the CSF. The subject's immunological profile was normal. The patient was treated with foscavir. Six weeks after clinical recovery and negative PCR, the patient presented with a unilateral acute retinal necrosis syndrome. Polymerase chain reaction of the aqueous humour was positive, while serology and PCR of the CSF remained negative.

CONCLUSION

Identification of the HSV-1 genome at the two successive sites of infection stresses the possibility of brain-to-eye transmission of HSV-1.

Infiltration of T-lymphocytes in the brain after anterior chamber inoculation of a neurovirulent and neuroinvasive strain of HSV-1

Following anterior chamber (AC) inoculation of BALB/c mice with the KOS strain of herpes simplex virus type 1 (HSV-1), or with H129, a neuroinvasive and neurovirulent strain of HSV-1, both strains of virus spread from the injected eye through the brain to cause retinitis. However, KOS-infected mice develop retinitis in the uninoculated eye only, whereas H129-infected mice develop bilateral retinitis. Previous studies have shown that infiltrating T-cells in the suprachiasmatic nuclei (SCN) of the hypothalamus of KOS-infected mice concomitant with or before virus protect KOS-infected mice from ipsilateral retinitis. To determine the timing of T cell infiltration and cytokine production in the brain of H129-infected mice, adjacent, frozen sections of the brain were immunostained for virus, T-cells, IL-2, TNF-alpha or IFN-gamma. T-cells infiltrated the brains of H129-infected mice and cytokines were produced in infected tissues. However, virus spread to the optic nerve and retina of both the inoculated and uninoculated eye before T-cells and cytokines were detected in the SCN of H129-infected mice. These results suggest that infiltrating T-cells in the SCN of H129-infected mice may arrive too late to prevent the spread of virus into the optic nerves and retinas and thus prevent development of bilateral retinitis in infected mice.

Rapid spread of a neurovirulent strain of HSV-1 through the CNS of BALB/c mice following anterior chamber inoculation

Following uniocular anterior chamber (AC) inoculation of BALB/c mice with the KOS strain of herpes simplex virus type 1 (HSV-1), virus spreads from the injected eye to the ipsilateral suprachiasmatic nucleus (SCN) in the central nervous system (CNS) to infect the optic nerve and retina of the contralateral eye, and mice develop retinitis in that eye only. In contrast, after AC inoculation of BALB/c mice with the H129 strain of HSV-1, mice develop bilateral retinitis. The pathway(s) by which H129 spreads to cause bilateral retinitis is not known. To determine the route and timing of H129 spread after AC inoculation, BALB/c mice were injected in the AC of the right eye with 5 x 10(3) PFU of H129. Brains from 30 mice were sectioned on a brain matrix and the amount of virus in the brain and eyes was determined by plaque assay. Frozen sections were prepared from the eyes, brain, and trigeminal ganglia of an additional 30 mice, and HSV-1 antigen was detected by immunohistochemistry. After AC inoculation, H129 follows a pathway similar to KOS in the CNS, but H129 appears to spread more rapidly than KOS within the CNS. Unlike KOS, H129 is able to infect brain stem nuclei and H129-infected mice developed neurological impairments in addition to bilateral retinitis. The results of these studies suggest that the ability of H129 to spread rapidly in the CNS allows early virus infection of retino-recipient nuclei proximal to the contralateral and ipsilateral optic nerves. Early infection of retino-recipient nuclei, such as the SCN may allow virus to spread into the retinas before a virus-specific immune response can be induced.

Acute retinal necrosis in children caused by herpes simplex virus

PURPOSE

To report the diagnosis, management, and outcome of acute retinal necrosis syndrome in children.

METHOD

Case series of three consecutive children aged 11 years and younger who were diagnosed with acute retinal necrosis. In addition to full ocular and systemic examinations, the children underwent vitreous biopsy (Patients 1 and 2) or aqueous tap (Patient 3) for polymerase chain reaction analysis.

RESULTS

All patients had unilateral retinitis that was associated with preexisting chorioretinal scars, and two patients (Patients 1 and 3) had concurrent extraocular central nervous system abnormalities. Intraocular herpes simplex virus was detected in all three children: Type 1 in Patient 1 and Type 2 in Patients 2 and 3. In addition, all three children had a history of extraocular herpes simplex virus infection.

CONCLUSIONS

Retinitis associated with preexisting chorioretinal scars and detectable intraocular herpes simplex virus on polymerase chain reaction was common to all three children with acute retinal necrosis.