Demonstration of varicella-zoster virus antigens in the vitreous aspirates of patients with acute retinal necrosis syndrome

Cytokines Produced in Response to Varicella-Zoster Virus Infection of ARPE-19 Cells Stimulate Lymphocyte Chemotaxis

Posterior uveitis is an ocular complication that can occur with reactivation of varicella-zoster virus (VZV). It may lead to loss of vision due to retinal detachment and chronic inflammation, which often causes more severe disease than the virus infection itself. To increase our understanding of the immune response, we infected the retinal pigment epithelial (RPE) cell line, ARPE-19, with cell-associated VZV and compared its response to that of the MeWo cell line using multiplex assays. We observed (1) a difference in the magnitude and kinetics of cytokine responses between the 2 cell types and (2) differential migration of CD4+ and CD8+ T cells towards these cytokines. Thus, our data provide information about the cytokine and lymphocytic responses to VZV infection of RPE cells, thereby providing a useful platform for future studies to address mechanisms underlying the immunopathology of VZV-associated posterior uveitis.

Varicella zoster virus infection: clinical features, molecular pathogenesis of disease, and latency

Varicella zoster virus (VZV) is an exclusively human neurotropic alphaherpesvirus. Primary infection causes varicella (chickenpox), after which virus becomes latent in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia along the entire neuraxis. Years later, in association with a decline in cell-mediated immunity in elderly and immunocompromised individuals, VZV reactivates and causes a wide range of neurologic disease. This article discusses the clinical manifestations, treatment, and prevention of VZV infection and reactivation; pathogenesis of VZV infection; and current research focusing on VZV latency, reactivation, and animal models.

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.

Sight-threatening varicella zoster virus infection after fludarabine treatment

Varicella zoster virus (VZV) infection involving the posterior segment of the eye after fludarabine treatment has not previously been described. Two patients, who had completed fludarabine treatment 3 and 18 months previously, presented with visual loss that had been preceded by a recent history of cutaneous zoster. The use of the polymerase chain reaction (PCR) for VZV DNA from ocular specimens allowed rapid confirmation of clinical diagnosis and treatment with a good outcome in one patient. With the increasing use of fludarabine and other purine analogues, an awareness of such complications is important because of their potentially sight-threatening consequences.

Necrotising herpetic retinopathy in patients with advance HIV disease

OBJECTIVES

To describe the presenting features, clinical and laboratory diagnosis, response to treatment, and outcome of necrotising herpetic retinopathy (NHR) in HIV infected patients.

METHODS

Retrospective case records/laboratory data review of five HIV infected patients presenting to the specialist HIV/AIDS unit at UCL Hospitals, London from April 1994 to August 1996 with a clinical diagnosis of NHR.

RESULTS

All patients had advanced HIV disease with a median CD4 count of 20.10(6)/1. Three patients had cutaneous varicella zoster virus (VZV) infection within the preceding 8 weeks. All had uniocular loss of visual acuity; one also had headache and another ocular pain. All had typical retinal appearances. VZV DNA was detected in cerebrospinal fluid of four patients (and in vitreous fluid of one of the four) and in vitreous fluid of one other. One patient refused therapy and rapidly became blind. Four patients received intravenous foscarnet with intravenous aciclovir for 6 weeks: three subsequently received oral famciclovir and one oral valaciclovir; two patients also had intravitreal injections of foscarnet. In none of the four did treatment bring about improvement in visual acuity, but in all four visual loss from retinitis was halted.

CONCLUSIONS

NHR occurs in HIV infected patients with advanced HIV disease and is strongly associated with evidence of VZV infection. With aggressive use of antiviral drugs the outcome is not uniformly poor.

Acute retinal necrosis caused by reactivation of herpes simplex virus type 2

Acute retinal necrosis is a severe form of necrotizing retinitis. Acute retinal necrosis has been demonstrated to be caused by varicella-zoster virus and herpes simplex virus type 1. We treated three patients with acute retinal necrosis apparently caused by recrudescence of latent herpes simplex virus type 2. Primary viral infection was probably congenital, with documented perinatal herpes simplex virus type 2 infection in two patients. Bilateral chorioretinal scars were present in two patients, neither of whom had a history of ocular herpetic infection, suggesting that earlier subclinical chorioretinitis had occurred. In each case, periocular trauma preceded the development of retinitis by two to three weeks. These cases are evidently caused by trauma-induced reactivation of latent virus rather than the onset of a primary infection.

Giant retinal pigment epithelial tears in acute retinal necrosis

We observed large peripheral tears of the retinal pigment epithelium in two patients, a 59-year-old man and a 15-year-old girl, who had acute retinal necrosis. These tears ranged from 90 to 180 degrees of the circumference of the peripheral retinal pigment epithelium and occurred in areas of previous retinal viral infection. Both patients had curled folds of tissue at the posterior edge of the retinal pigment epithelial tear. During vitrectomy at the time of fluid-air exchange, we noted the edge of these tears to sag posteriorly. Because of the area that was denuded of retinal pigment epithelium by the tears, we selected a more posterior location for argon laser endophotocoagulation in both patients. These large retinal pigment epithelial tears did not appear to have an adverse effect on the outcome of surgical treatment of the retinal detachments.

Hemodynamic alterations in the acute retinal necrosis syndrome

BACKGROUND

Clinical and histopathologic observations suggest a role for ischemia in the pathogenesis of the acute retinal necrosis (ARN) syndrome. Disruption of blood flow appears to occur at some level in the retina or choroid and may account for some of the major features of the syndrome.

METHODS

To investigate these potential circulatory changes, color Doppler imaging (CDI) was used to quantitate blood flow velocities and vascular resistance in the central retinal, ophthalmic, and short posterior ciliary arteries in ten consecutive patients with unilateral ARN syndrome. Data were analyzed with a paired Student's t test. The unaffected fellow eyes served as controls.

RESULTS

Blood flow velocities within the central retinal artery were significantly reduced in eyes with ARN syndrome compared with control eyes. In affected eyes, there was a mean reduction of 55%, 60%, and 72% in peak systolic, average, and end-diastolic velocities, respectively (P < 0.01). The calculated vascular resistance of the central retinal artery showed an upward trend, but the data fell short of statistical significance. Blood flow velocities from the ophthalmic and short posterior ciliary arteries were not significantly different compared with controls.

CONCLUSIONS

This study demonstrates marked circulatory changes in the central retinal artery of eyes involved with the ARN syndrome. Although the exact mechanism and clinical significance are yet to be determined, the data support the presence of retinal arterial hemodynamic compromise in this condition.

Polymerase chain reaction for the detection of the varicella-zoster genome in ocular samples from patients with acute retinal necrosis

We used the polymerase chain reaction to detect the virus genome in ocular samples from patients with clinically diagnosed acute retinal necrosis. Four samples from four patients with acute retinal necrosis, and five samples from three patients with other ocular diseases (sarcoidosis, rhegmatogenous retinal detachment, and epiretinal membrane of unknown origin) were evaluated. The samples consisted of aqueous humor, vitreous, or subretinal fluid. Primers were specific for varicella-zoster virus, herpes simplex virus, or cytomegalovirus. The varicella-zoster virus genome was detected in three of the four samples from patients with acute retinal necrosis. Among these three positive samples, two had PstI-site-less point mutation, strains that have been described only in Japan and of low prevalence. Samples from patients with diagnoses other than acute retinal necrosis yielded negative results when varicella-zoster virus primer was used. No sample was positive for herpes simplex virus or cytomegalovirus primers.

Herpesvirus antibody levels in the etiologic diagnosis of the acute retinal necrosis syndrome

Quantitative antibody levels to three herpesviruses in acute and chronic sera from six patients with clinical signs of the acute retinal necrosis syndrome were consistent with a specific etiologic diagnosis only in the two cases associated with cutaneous herpes zoster. Available data on acute and convalescent antibody titers to herpes group viruses from these six patients in addition to data from 27 acute retinal necrosis cases from the literature disclosed that only 13 of the 33 patients (39%) had a diagnostic increase or decrease in herpes group viral antibody levels on serial sampling. Three patients had nondiagnostic changes in viral antibody levels despite positive vitreous cultures for herpesviruses. In contrast, a review of 25 cases from the literature with paired antiviral serum and intraocular fluid antibody levels suggested a more promising approach to the etiologic diagnosis of the acute retinal necrosis syndrome. By calculating the ratio of antiviral antibodies in intraocular fluid and serum, an etiologic diagnosis could be made in 12 of 14 (86%) of subacute and convalescent samples. The sensitivity of this method decreased to 72% (13 of 18) when fluids were obtained earlier in the course of the disease.

Decrease in the risk of bilateral acute retinal necrosis by acyclovir therapy

We reviewed the course of 54 patients who had unilateral acute retinal necrosis at initial examination. Thirty-one patients were treated with acyclovir, whereas 23 were not. Of the 31 patients treated with acyclovir, 27 (87.1%) had fellow eyes that remained disease-free throughout a median follow-up of 12 months. Of the 23 patients not treated with acyclovir, seven (30.4%) had fellow eyes that remained disease-free throughout a median follow-up of 11 months. Survival analysis indicated that the fellow eyes of the group of patients treated with acyclovir were more likely to remain disease-free than the fellow eyes of the group not treated with acyclovir (P = .0013). Two years after initial onset, the proportion of fellow eyes that remained disease-free was 75.3% for the group treated with acyclovir and 35.1% for the group not treated with acyclovir. These results suggest that acyclovir treatment reduces the risk of involvement of the fellow eye in patients with acute retinal necrosis.

Surgical management of retinal detachment associated with the acute retinal necrosis syndrome

We operated on nine eyes in eight patients with retinal detachment associated with acute retinal necrosis (ARN) syndrome. The patients were treated with scleral buckling, vitreoretinal surgery, or a combination of these treatments. Vitrectomised eyes underwent combinations of lensectomy, membrane dissection, scleral buckling, air-fluid exchange, endolaser photocoagulation, cryotherapy, and retinal tamponade with C3F8 gas or SF6 gas. Macular attachment was achieved in eight (89%) eyes. Vision improved in seven (78%) eyes, of which five (56%) achieved 20/200 or better vision. Three eyes that had received laser treatment posterior to areas of retinitis suffered retinal detachment despite this prophylactic treatment. Poor visual outcome resulted from viral infection of the optic nerve or macular involvement, macular hole formation, macular pucker, or hypotony.

Acute retinal necrosis syndrome

Acute retinal necrosis (ARN) is a rare syndrome with characteristic fundal appearances which can have devastating effects on vision. We present six cases (nine eyes) seen in the Medical Eye Unit of St Thomas's Hospital over the past six years and discuss the clinical features, aetiology, and management. Our findings support the present consensus that the condition is caused by varicella zoster virus (VZV) or herpes simplex virus (HSV). One of our patients, who was atypical in having common variable hypogammaglobulinaemia, had suffered a widespread zosteriform rash immediately prior to the onset of ARN, while another had suffered a herpes simplex uveomeningoencephalitis. All cases had characteristic confluent peripheral retinal necrosis, and three of the nine eyes developed retinal detachment. Retinal arteritis was a prominent and helpful diagnostic feature in one case. From combining all reports to date of this rare condition it is possible to conclude that ARN is unilateral in 65% of cases.

Diagnosis and management of the acute retinal necrosis (ARN) syndrome

The acute retinal necrosis (ARN) syndrome represents a specific pattern of clinical presentation for certain herpes virus infections in the posterior segment of the eye. The classically described triad of the ARN syndrome consists of (1) an arteritis and phlebitis of the retinal and choroidal vasculature, (2) a confluent, necrotizing retinitis that preferentially affects the peripheral retina, and (3) a moderate to severe vitritis. Anterior segment inflammation, optic neuritis, and late retinal detachment are also common features of this disorder. Definitive evidence now implicates at least two members of the herpes virus family; varicella zoster virus and herpes simplex virus as causative agents. This paper summarizes the clinical presentation, as well as the currently recommended treatment regimen for the ARN syndrome, highlighting recent advances that have resulted in a significant improvement in the visual prognosis for affected patients.