Herpes simplex eye infections: clinical manifestations, pathogenesis and management

Herpetic Keratouveitis: Missed Diagnosis Leading to Corneal Perforation

Herpetic uveitis is an easy diagnosis to miss, which can lead to devastating consequences. The aim of this report is to create awareness of how this disease can present, appropriate clues to the diagnosis, and how it should be managed. We report a case of a 70-year-old female who presented with redness and painless blurry vision in her right eye and was treated with topical corticosteroid drops for presumed idiopathic anterior uveitis. Despite initial symptomatic improvement, she reattended with a significant deterioration in vision and was found to have a large corneal infiltrate and associated perforation. The perforation was sealed with corneal gluing, and she was treated for presumed herpetic anterior uveitis with oral acyclovir. Corneal polymerase chain reaction (PCR) specimen was positive for herpes simplex virus DNA. The perforation started to leak again despite repeat corneal gluing, so an emergency therapeutic penetrating keratoplasty was performed. She has remained on prophylactic oral acyclovir for the last 24 months, with no recurrence and the graft remains clear.

Managing Corneal Infections: Out with the old, in with the new?

There have been multiple reports of eye infections caused by antibiotic-resistant bacteria, with increasing evidence of ineffective treatment outcomes from existing therapies. With respect to corneal infections, the most commonly used antibiotics (fluoroquinolones, aminoglycosides, and cephalosporines) are demonstrating reduced efficacy against bacterial keratitis isolates. While traditional methods are losing efficacy, several novel technologies are under investigation, including light-based anti-infective technology with or without chemical substrates, phage therapy, and probiotics. Many of these methods show non-selective antimicrobial activity with potential development as broad-spectrum antimicrobial agents. Multiple preclinical studies and a limited number of clinical case studies have confirmed the efficacy of some of these novel methods. However, given the rapid evolution of corneal infections, their treatment requires rapid institution to limit the impact on vision and prevent complications such as scarring and corneal perforation. Given their rapid effects on microbial viability, light-based technologies seem particularly promising in this regard.

Disease parameters following ocular herpes simplex virus type 1 infection are similar in male and female BALB/C mice

Sex related differences in the incidence or severity of infection have been described for multiple viruses. With herpes simplex viruses, the best example is HSV-2 genital infection where women have a higher incidence of infection and can have more severe infections than men. HSV-1 causes several types of infections including skin and mucosal ulcers, keratitis, and encephalitis in humans that do not appear to have a strong biological sex component. Given that mouse strains differ in their MHC loci it is important to determine if sex differences occur in multiple strains of mice. Our goal was to answer two questions: Are virus related sex differences present in BALB/C mice and does virulence of the viral strain have an effect? We generated a panel of recombinant HSV-1 viruses with differing virulence phenotypes and characterized multiple clinical correlates of ocular infection in BALB/c mice. We found no sex-specific differences in blepharitis, corneal clouding, neurovirulence, and viral titers in eye washes. Sex differences in neovascularization, weight loss and eyewash titers were observed for some recombinants, but these were not consistent across the phenotypes tested for any recombinant virus. Considering these findings, we conclude that there are no significant sex specific ocular pathologies in the parameters measured, regardless of the virulence phenotype following ocular infection in BALB/c mice, suggesting that the use of both sexes is not necessary for the bulk of ocular infection studies.

Current landscape in antiviral drug development against herpes simplex virus infections

Herpes simplex viruses (HSV) are common human pathogens with a combined global seroprevalence of 90% in the adult population. HSV-1 causes orofacial herpes but can cause severe diseases, such as the potentially fatal herpes encephalitis and herpes keratitis, a prevalent cause of infectious blindness. The hallmark of HSV is lifelong latent infections and viral reactivations, leading to recurrent lesions or asymptomatic shedding. HSV-1 and HSV-2 can cause recurrent, painful, and socially limiting genital lesions, which predispose to human immunodeficiency virus infections, and can lead to neonatal herpes infections, a life-threatening condition for the newborn. Despite massive efforts, there is no vaccine against HSV, as both viruses share the capability to evade the antiviral defenses of human and to establish lifelong latency. Recurrent and primary HSV infections are treated with nucleoside analogs, but the treatments do not completely eliminate viral shedding and transmission. Drug-resistant HSV strains can emerge in relation to long-term prophylactic treatment. Such strains are likely to be resistant to other chemotherapies, justifying the development of novel antiviral treatments. The importance of developing new therapies against HSV has been recognized by the World Health Organization. In this review, we discuss the current approaches for developing novel antiviral therapies against HSV, such as small molecule inhibitors, biopharmaceuticals, natural products, gene editing, and oligonucleotide-based therapies. These approaches may have potential in the future to answer the unmet medical need. Furthermore, novel approaches are presented for potential eradication of latent HSV.

Swarms of chemically modified antiviral siRNA targeting herpes simplex virus infection in human corneal epithelial cells

Herpes simplex virus type 1 (HSV-1) is a common virus of mankind and HSV-1 infections are a significant cause of blindness. The current antiviral treatment of herpes infection relies on acyclovir and related compounds. However, acyclovir resistance emerges especially in the long term prophylactic treatment that is required for prevention of recurrent herpes keratitis. Earlier we have established antiviral siRNA swarms, targeting sequences of essential genes of HSV, as effective means of silencing the replication of HSV in vitro or in vivo. In this study, we show the antiviral efficacy of 2´-fluoro modified antiviral siRNA swarms against HSV-1 in human corneal epithelial cells (HCE). We studied HCE for innate immunity responses to HSV-1, to immunostimulatory cytotoxic double stranded RNA, and to the antiviral siRNA swarms, with or without a viral challenge. The panel of studied innate responses included interferon beta, lambda 1, interferon stimulated gene 54, human myxovirus resistance protein A, human myxovirus resistance protein B, toll-like receptor 3 and interferon kappa. Our results demonstrated that HCE cells are a suitable model to study antiviral RNAi efficacy and safety in vitro. In HCE cells, the antiviral siRNA swarms targeting the HSV UL29 gene and harboring 2´-fluoro modifications, were well tolerated, induced only modest innate immunity responses, and were highly antiviral with more than 99% inhibition of viral release. The antiviral effect of the 2’-fluoro modified swarm was more apparent than that of the unmodified antiviral siRNA swarm. Our results encourage further research in vitro and in vivo on antiviral siRNA swarm therapy of corneal HSV infection, especially with modified siRNA swarms.

Herpes simplex virus type 1 (HSV-1) is a common virus carried approximately by half of the global population. Though it is mostly known by causing cold sores, it also causes herpes keratitis, which is the leading cause of infectious blindness in the world. The treatment for herpes keratitis and other severe disease forms of herpes infection is insufficient, as resistant variants arise upon long-term prophylactic treatments. We have earlier developed an anti-HSV siRNA swarm, which has proven safe and effective in many cell types, in animal models, and against variants resistant to current first-in-line treatment. Most recently, we added modifications to the anti-HSV siRNA swarm, which increased its efficacy and stability. In this study, we show the efficacy and safety of the modified anti-HSV siRNA swarm in a cell line representing the treatment target tissue in herpes keratitis. Our results show that our modified anti-HSV siRNA swarm is a possibility for future therapy for herpes keratitis. The results encourage further research in an animal model of herpes keratitis in order to uncover the potential of our modified anti-HSV siRNA swarm.

Evidence in the prevention of the recurrence of herpes simplex and herpes zoster keratitis after eye surgery

OBJECTIVE

Herpetic keratitis, either due to herpes simplex keratitis (HSK) or herpes zoster ophthalmicus (HZO), can recur after eye surgery.º Prophylaxis is postulated as necessary to avoid it. The objective of this study was to review the scientific evidence on the preventive methods used in the perioperative period in patients previously affected by HSK/HZO.

METHODS

An exhaustive search was carried out in the PubMed and Web of Science databases to identify relevant articles on prophylaxis and risk of recurrence of HSK/HZO in patients undergoing eye surgery up to 31 December 2019.

RESULTS

There is strong evidence that oral prophylaxis should be recommended after penetrating keratoplasty in patients who have previously had HSK/HZO. For other types of surgery, the evidence is less compelling. However, a latent period of inactivity should be considered between disease and oral prophylaxis.

CONCLUSIONS

Penetrating and lamellar keratoplasty, corneal crosslinking, cataract surgery, and photorefractive and phototherapeutic surgery cause an alteration of the subbasal nerve plexus of the cornea. Due to surgical trauma, as well as the modulation of the ocular immune response caused by steroids applied in the postoperative period, it is possible to induce the reactivation of HSK/HZO, which is common in some cases. Within this article, we discuss the available evidence for HSK/HZO prophylaxis in eye surgery. Further studies are necessary to define the real risk of HSK/HZO recurrence after ocular surgeries, particularly in cataract surgery, and to confirm the efficacy of perioperative prophylaxis with anti-HSK/HZO antivirals.

Adoption of Innovation in Herpes Simplex Virus Keratitis

Herpes simplex keratitis, caused primarily by human herpes simplex virus type 1 (HSV-1), remains the most common infectious cause of unilateral blindness and vision impairment in the industrialized world. Major advances in the care of HSV keratitis have been driven in large part by the landmark Herpetic Eye Disease Study randomized clinical trials, which were among the first in ophthalmology to reflect emerging trial conventions, including multicenter subject enrollment, double-masking, placebo controls, and a priori sample size determinations. The results of these trials now form much of the evidence basis for the management of this disease. However, management patterns in clinical practice often deviate from evidence-based care. These perceived quality gaps have given rise to the evolving field of implementation science, which is concerned with the methods of promoting the application of evidence-based medicine within routine care. To overcome variations in the quality and consistency of care for HSV keratitis, a range of clinical- and technology-based innovations are proposed. The most pressing needs include the following: a rational and tractable disease classification scheme that provides an immediate link between the anatomical localization of disease (corneal epithelial, stromal, or endothelial) and the appropriate treatment, and the actualization of an electronic medical record system capable of providing evidence-based treatment algorithms at relevant points of care. The latter would also input data to population-wide disease registries to identify implementation-rich targets for quality improvement, education, and research. These innovations may allow us to reduce the human and economic burdens of this highly morbid, and often blinding, disease.

Thygeson's superficial punctate keratopathy: A review and case series

Thygeson's superficial punctate keratitis (TSPK) is a chronic disorder with episodes of exacerbations and remissions which span over years to decades. Typical features of the disease include multiple, grayish white, intraepithelial corneal lesions with minimal or no conjunctival involvement. The exact etiopathogenesis of this entity is unknown. However, it may have a genetic association with HLA-DR3, an antigen proved to be associated with immunogenic responses. Treatment of the disease consists of artificial tears, topical corticosteroids, topical cyclosporine, topical tacrolimus, or usage of soft contact lenses. TSPK should be considered as a diagnosis of exclusion in cases of bilateral superficial punctate keratopathy of long duration. Thirteen patients of TSPK were examined during the last 6 years (2014-2019) at our Institute. Visual acuity was 20/20 to 20/30 in majority cases. All patients required lubricants.

Herpes simplex virus 1 targets IRF7 via ICP0 to limit type I IFN induction

Herpes simplex keratitis (HSK), caused by herpes simplex virus type 1 (HSV-1) infection, is the commonest cause of infectious blindness in the developed world. Following infection the virus is initially suspended in the tear film, where it encounters a multi-pronged immune response comprising enzymes, complement, immunoglobulins and crucially, a range of anti-viral and pro-inflammatory cytokines. However, given that HSV-1 can overcome innate immune responses to establish lifelong latency throughout a susceptible individual's lifetime, there is significant interest in understanding the mechanisms employed by HSV-1 to downregulate the anti-viral type I interferon (IFN) mediated immune responses. This study aimed to investigate the interactions between infected cell protein (ICP)0 and key elements of the IFN pathway to identify possible novel targets that contribute to viral immune evasion. Reporter gene assays demonstrated the ability of ICP0 to inhibit type I IFN activity downstream of pathogen recognition receptors (PRRs) which are known to be involved in host antiviral defences. Further experiments identified interferon regulatory factor (IRF)7, a driver of type I IFN, as a potential target for ICP0. These findings increase our understanding of the pathogenesis of HSK and suggest IRF7 as a potential therapeutic target.

Limbal Stem Cell Deficiency Associated With Herpes Keratitis

PURPOSE

To describe the demographic features and clinical characteristics of patients with herpes keratitis (HK) and limbal stem cell deficiency (LSCD) and identify possible factors associated with development of LSCD after HK.

METHODS

In this retrospective case-series study, records of patients with a clinical diagnosis of HK seen at Massachusetts Eye and Ear over a 5-year period were reviewed for evidence of LSCD. Patient demographics, medical history, treatment, and best-corrected visual acuities (BCVAs) were recorded.

RESULTS

We identified 626 patients with HK. Fifty-seven had been diagnosed with LSCD (9.3%). Thirteen percent of patients with herpes zoster keratitis (N= 25) and 7% of patients with herpes simplex keratitis (N= 32) had LSCD (P = 0.01). Keratitis caused by herpes zoster virus [odds ratios (OR), 1.77; 95% confidence interval (CI), 0.97-3.19; P = 0.01], stromal involvement (OR, 2.28; 95% CI, 1.27-4.18; P = 0.02), and the use of topical antihypertensives (OR, 2.28; 95% CI, 1.27-4.18; P = 0.02) were found to be associated with a higher likelihood of developing LSCD. The final logarithm of the minimum angle of resolution (LogMAR) BCVA was significantly lower in patients with LSCD compared with those without LSCD with a mean BCVA of 1.34 ± 1.52 LogMar (∼20/200) as compared to 0.18 ± 0.54 LogMar (∼20/30 ± 20/60) in those patients without LSCD (P = 0.005).

CONCLUSIONS

Our data suggest that HK may be a risk factor for development of LSCD. Patients with HK should be monitored for the development of LSCD to reduce the risk of chronic ocular surface morbidity.

Ocular surgery after herpes simplex and herpes zoster keratitis

PURPOSE

The recurrence of herpetic stromal keratitis (HSK) and herpes zoster ophthalmicus (HZO) has been reported after a variety of ocular surgeries. The aim of this study was to review the evidence on the preventive methods employed in the perioperative period in patients having undergone HSK/HZO.

METHODS

The PubMed and Web of Science databases were the main resources used to conduct the medical literature search. An extensive search was performed to identify relevant articles concerning the prophylaxis against and risk of HSK/HZO recurrence in patients undergoing ocular surgery up to December 31, 2019.

RESULTS

The disturbance of the corneal nerve plexus occurs during several ocular surgeries including penetrating keratoplasty, lamellar keratoplasty, corneal cross-linking, cataract surgery, as well as photorefractive and phototherapeutic procedures. Such trauma, as well as modulation of the ocular immunological response caused by steroids applied postoperatively, might engender the HSK/HZO reactivation which is not uncommon. There is strong evidence that oral prophylaxis should be recommended just after surgery in patients undergoing penetrating keratoplasty and having suffered from HSK/HZO. For other types of surgeries, the evidence is less compelling; nevertheless, a period of disease quiescence and oral prophylaxis should still be considered.

CONCLUSIONS

Within the article, we discuss the available evidence for HSK/HZO prophylaxis in ocular surgery. Additional studies would be required to define the real risk of HSK/HZO recurrence following eye surgeries, and particularly cataract surgery, and to confirm the utility of perioperative HSK/HZO prophylaxis.

The presence and impact of herpes virus DNA in recipient cornea and aqueous humor on graft survival following penetrating keratoplasty

BACKGROUND/PURPOSE

Reactivation of herpes viruses poses threat to corneal graft survival. This study evaluated the presence of herpes simplex virus type 1 (HSV-1), HSV type 2 (HSV-2), and cytomegalovirus (CMV) DNA in recipient corneas and the aqueous humor of patients undergoing penetrating keratoplasty (PKP), and the impact on graft survival.

METHODS

This retrospective study reviewed 90 eyes of 71 patients underwent PKP between 2008 and 2016. Cornea and aqueous humor samples were sent for polymerase chain reaction (PCR) testing for viral DNA. The main outcomes were PCR results and graft survival.

RESULTS

Recipient corneas tested positive for HSV-1 in 47 eyes (52.2%), for HSV-2 in 24 eyes (26.7%), and for CMV in seven eyes (7.8%). Aqueous humor tested positive for HSV-1 in 44 eyes (48.9%), for HSV-2 in 25 eyes (27.8%), and for CMV in eight eyes (8.9%). The presence of aqueous HSV-1 DNA was associated with higher risk of graft failure (p = 0.005), whereas corneal HSV-1 DNA was not. The presence of HSV-2 DNA had no significant impact on graft survival. Aqueous CMV DNA was associated with higher risk of graft failure in univariate model, but not in multivariate model.

CONCLUSION

There were high positive rates of HSV-1, HSV-2, and CMV DNA in recipient corneas and aqueous humor at the time of PKP, even among patients not suspected of latent viral infection. The presence of aqueous HSV-1 DNA was associated with higher risk of graft failure.

Early Steps in Herpes Simplex Virus Infection Blocked by a Proteasome Inhibitor

Viruses commandeer host cell 26S proteasome activity to promote viral entry, gene expression, replication, assembly, and egress. Proteasomal degradation activity is critical for herpes simplex virus (HSV) infection. The proteasome inhibitor bortezomib (also known as Velcade and PS-341) is a clinically effective antineoplastic drug that is FDA approved for treatment of hematologic malignancies such as multiple myeloma and mantle cell lymphoma. Low nanomolar concentrations of bortezomib inhibited infection by HSV-1, HSV-2, and acyclovir-resistant strains. Inhibition coincided with minimal cytotoxicity. Bortezomib did not affect attachment of HSV to cells or inactivate the virus directly. Bortezomib acted early in HSV infection by perturbing two distinct proteasome-dependent steps that occur within the initial hours of infection: the transport of incoming viral nucleocapsids to the nucleus and the virus-induced disruption of host nuclear domain 10 (ND10) structures. The combination of bortezomib with acyclovir demonstrated synergistic inhibitory effects on HSV infection. Thus, bortezomib is a novel potential therapeutic for HSV with a defined mechanism of action.IMPORTANCE Viruses usurp host cell functions to advance their replicative agenda. HSV relies on cellular proteasome activity for successful infection. Proteasome inhibitors, such as MG132, block HSV infection at multiple stages of the infectious cycle. Targeting host cell processes for antiviral intervention is an unconventional approach that might limit antiviral resistance. Here we demonstrated that the proteasome inhibitor bortezomib, which is a clinically effective cancer drug, has the in vitro features of a promising anti-HSV therapeutic. Bortezomib inhibited HSV infection during the first hours of infection at nanomolar concentrations that were minimally cytotoxic. The mechanism of bortezomib's inhibition of early HSV infection was to halt nucleocapsid transport to the nucleus and to stabilize the ND10 cellular defense complex. Bortezomib and acyclovir acted synergistically to inhibit HSV infection. Overall, we present evidence for the repurposing of bortezomib as a novel antiherpesviral agent and describe specific mechanisms of action.

A synthetic glycosaminoglycan mimetic blocks HSV-1 infection in human iris stromal cells

Herpes simplex virus type-1 (HSV-1) is a significant pathogen that affects vision by targeting multiple regions in the human eye including iris. Using a focused library of synthetic non-saccharide glycosaminoglycan mimetics (NSGMs), we identified sulfated pentagalloylglucoside (SPGG) as a potent inhibitor of HSV-1 entry and cell-to-cell spread in the primary cultures of human iris stromal (HIS) cells isolated from eye donors. Using in vitro β-galactosidase reporter assay and plaque reduction assay, SPGG was found to inhibit HSV-1 entry in a dosage-dependent manner (IC₅₀ ∼6.0 μM). Interestingly, a pronounced inhibition in HSV-1 entry and spread was observed in HIS cells, or a cell line expressing specific gD-receptor, when virions were pre-treated with mimetics suggesting a possible interaction between SPGG and the HSV-1 glycoprotein. To examine the significance of gD-SPGG interaction, HIS cells were pretreated with SPGG, which showed a significant reduction in gD binding. Taken together, our results provide strong evidence of SPGG being a novel viral entry inhibitor against ocular HSV infection.

Using phase II data for the analysis of phase III studies: An application in rare diseases

BACKGROUND

Clinical research and drug development in orphan diseases are challenging, since large-scale randomized studies are difficult to conduct. Formally synthesizing the evidence is therefore of great value, yet this is rarely done in the drug-approval process. Phase III designs that make better use of phase II data can facilitate drug development in orphan diseases.

METHODS

A Bayesian meta-analytic approach is used to inform the phase III study with phase II data. It is particularly attractive, since uncertainty of between-trial heterogeneity can be dealt with probabilistically, which is critical if the number of studies is small. Furthermore, it allows quantifying and discounting the phase II data through the predictive distribution relevant for phase III. A phase III design is proposed which uses the phase II data and considers approval based on a phase III interim analysis. The design is illustrated with a non-inferiority case study from a Food and Drug Administration approval in herpetic keratitis (an orphan disease). Design operating characteristics are compared to those of a traditional design, which ignores the phase II data.

RESULTS

An analysis of the phase II data reveals good but insufficient evidence for non-inferiority, highlighting the need for a phase III study. For the phase III study supported by phase II data, the interim analysis is based on half of the patients. For this design, the meta-analytic interim results are conclusive and would justify approval. In contrast, based on the phase III data only, interim results are inconclusive and require further evidence.

CONCLUSION

To accelerate drug development for orphan diseases, innovative study designs and appropriate methodology are needed. Taking advantage of randomized phase II data when analyzing phase III studies looks promising because the evidence from phase II supports informed decision-making. The implementation of the Bayesian design is straightforward with public software such as R.

Tear HSV-specific secretory IgA as a potential indicator for recurrent stromal herpes simplex keratitis: a preliminary study

PURPOSE

To assess the herpes simplex virus-specific tear secretory IgA (sIgA) and its correlation with specific serum antibodies and to evaluate the possible value of specific tear sIgA for prediction of herpes simplex keratitis (HSK) recurrence.

METHODS

Tear sIgA and paired serum IgG/IgM/IgA from 41 stromal HSK patients and 15 controls were analyzed by enzyme-linked immunosorbent assay. Subsequent follow-up for monitoring recurrence was performed from the time of first cure on all patients for 4 months to 1 year.

RESULTS

Serum IgG was positive in all participants. The concentration of serum IgA increased with the levels of tear sIgA (P = 0.017). The tear sIgA-positive rate was 36.59% in stromal keratitis, whereas none of the controls were found as sIgA positive. Positivity of sIgA was the only potential factor for predicting the risk of herpes keratitis recurrence (hazard ratio = 9.04; 95% confidence interval, 1.06-77.44; P = 0.045), with a sensitivity of 83.3% and a specificity of 71.4% (P = 0.034; 95% confidence interval, 0.58-0.97). Tear sIgA-positive patients had significantly shorter relapse-free survival compared with tear sIgA-negative patients (P = 0.015).

CONCLUSIONS

This is the first preliminary study suggesting that the levels of tear sIgA could be a potential prognostic parameter for the recurrence of HSK.

Controlling herpetic stromal keratitis by modulating lymphotoxin-alpha-mediated inflammatory pathways

Herpes simplex virus 1 infection of the eye can result in stromal keratitis, a chronic immunoinflammatory lesion that is a significant cause of human blindness. A key to controlling the severity of lesions is to identify cellular and molecular events responsible for tissue damage. This report evaluates the role of lymphotoxin-α, a proinflammatory cytokine that could be involved during stromal keratitis. We demonstrate that after infection, both lymphotoxin-α and lymphotoxin-β transcripts are detectable at high levels 48 h postinfection, suggesting roles for the secreted homotrimer lymphotoxin-α3 and the membrane-bound lymphotoxin-α1β2 heterotrimer in stromal keratitis. Using a corneal stromal fibroblast cell line, lymphotoxin-α3 and lymphotoxin-α1β2 were found to have proinflammatory roles by stimulating production of chemokines. Treatment of mice with a depleting anti-lymphotoxin-α mAb during the clinical phase of the disease significantly attenuated stromal keratitis lesions. In treated mice, expression of proinflammatory molecules and chemokines was reduced, as were numbers of cornea-infiltrating proinflammatory cells, particularly Th1 cells. The protective effect of anti-lymphotoxin-α mAb was highly reduced with a mutant version of the mAb that lacks Fc receptor binding activity, indicating that depletion of lymphotoxin-expressing cells was mainly responsible for efficacy, with LT-α3 contributing minimally to inflammation. These data demonstrate that lymphotoxin-expressing cells, such as Th1 cells, mediate stromal keratitis.

Viral ocular manifestations: a broad overview

The viruses able to affect the eye are taxonomically diverse, ranging from double-stranded DNA viruses, to single stranded RNA viruses, to retroviruses. Any part of the eye may be affected, frequently producing blepharitis, conjunctivitis, keratitis, uveitis, cataract and retinitis. The more common ocular viral infections include the Herpesviruses such as HSV-1, VZV and CMV. The HIV pandemic is placing a serious burden on ophthalmology clinics, particularly in sub-Saharan Africa as the number of viral ocular diseases is increasing. In particular, CMV retinitis is becoming more prevalent where antiretroviral therapy is not available and is replaced by immune-recovery uveitis where antiretrovirals are given. This review aims to improve knowledge of the common viral ocular diseases, their diagnosis and management, as well as the fairly uncommon viral ocular diseases that may also cause considerable morbidity.

Presumed Herpetic Anterior Uveitis: A Study with Retrospective Analysis of 79 Cases

Purpose

To describe the clinical features, visual outcome, medical treatment, and complications of presumed herpetic anterior uveitis.

Methods

We retrospectively analyzed the clinical data related to 79 eyes of 77 patients with presumed herpetic anterior uveitis seen at the Uveitis Unit of the Ulucanlar Eye Training and Research Hospital from 1996 to 2011. Age at onset of disease, sex, follow-up duration, existence of corneal involvement, posterior synechiae, distorted pupil, iris atrophy, characteristic of keratic precipitates, elevated intraocular pressure (IOP), medical treatment, recurrence rate, complications, visual acuities (VA), and surgery for complications were recorded. The complication rates in patients with and without corneal involvement were compared.

Results

There were 38 (49.4%) female and 39 (50.6%) male patients. The mean age at presentation was 48.5 ± 14.8 (20–82) years. The follow-up period was 26.5 (2–127) months. Two patients had bilateral involvement. Ocular findings were a corneal scar or active keratitis in 37 (46.8%) eyes, secondary glaucoma in 14 (17.7%), iris atrophy in 39 (49.4%), distorted pupil in 16 (20.3%), posterior synechiae in 23 (29.1%), and granulomatous anterior uveitis in 30 (40%) eyes. Eight (10.1%) eyes had a posterior subcapsular cataract. Glaucoma surgery was required for uncontrolled IOP with maximum medical treatment in 2 (2.4%) eyes. Long-term oral acyclovir was used in 9 (11.3%) patients. Final VA was ≤ 0.1 in 8 (10.1%) eyes; of these, 6 had either corneal scarring or cataract and 2 preexisting amblyopia.

Conclusions

Presumed herpetic anterior uveitis with or without keratitis has characteristic clinical findings that enable the diagnosis. Long-term prophylactic antiviral therapy should be considered especially in patients <50 years old.

Susceptibility of human iris stromal cells to herpes simplex virus 1 entry

Ocular herpes simplex virus 1 (HSV-1) infection can lead to multiple complications, including iritis, an inflammation of the iris. Here, we use human iris stroma cells as a novel in vitro model to demonstrate HSV-1 entry and the inflammatory mediators that can damage the iris. The upregulated cytokines observed in this study provide a new understanding of the intrinsic immune mechanisms that can contribute to the onset of iritis.

Herpes simplex epithelial and stromal keratitis: an epidemiologic update

Herpes simplex virus (HSV) is associated with a variety of ocular diseases, including epithelial and stromal keratitis. HSV can cause stromal opacification and is believed to be the leading cause of infectious blindness in the developed world. An improved understanding of the global burden of HSV keratitis, including the incidence of severe vision loss, could have a significant effect on prevention and treatment and place it in perspective among causes of corneal ulceration. We found that the global incidence of HSV keratitis is roughly 1.5 million, including 40,000 new cases of severe monocular visual impairment or blindness each year. We also discuss relevant epidemiologic issues regarding HSV epithelial and stromal disease.

Cellular changes of the corneal epithelium and stroma in herpes simplex keratitis: an in vivo confocal microscopy study

PURPOSE

To analyze the morphologic features of corneal epithelial cells and keratocytes by in vivo confocal microscopy in patients with herpes simplex keratitis (HSK) as associated with corneal innervation.

DESIGN

Prospective, cross-sectional, controlled, single-center study.

PARTICIPANTS

Thirty-one eyes with the diagnosis HSK and their contralateral clinically unaffected eyes were studied and compared with normal controls (n = 15).

METHODS

In vivo confocal microscopy (Confoscan 4; Nidek Technologies, Gamagori, Japan) and corneal esthesiometry (Cochet-Bonnet; Luneau Ophthalmologie, Chartres, France) of the central cornea were performed bilaterally in all patients and controls. Patients were grouped into normal (>5.5 cm), mild (>2.5-5.5 cm), and severe (<2.5 cm) loss of sensation.

MAIN OUTCOME MEASURES

Changes in morphologic features and density of the superficial and basal epithelial cells, as well as stromal keratocytes, were assessed by 2 masked observers. Changes were correlated to corneal sensation, number of nerves, and total length of nerves.

RESULTS

There was a significant and gradual decrease in the density of superficial epithelial cells in HSK eyes, with 852.50 ± 24.4 cells/mm(2) in eyes with severe sensation loss and 2435.23 ± 224.3 cells/mm(2) in control eyes (P = 0.008). Superficial epithelial cell size was 2.5-fold larger in HSK eyes (835.3 μm(2)) compared with contralateral or normal eyes (407.4 μm(2); P = 0.003). A significant number of hyperreflective desquamating superficial epithelial cells were present in HSK eyes with normal (6.4%), mild (29.1%), and severe (52.2%) loss of sensation, but were absent in controls. The density of basal epithelial cells, anterior keratocytes, and posterior keratocytes did not show statistical significance between patients and controls. Changes in superficial epithelial cell density and morphologic features correlated strongly with total nerve length, number, and corneal sensation. Scans of contralateral eyes did not show any significant epithelial or stromal changes compared with controls.

CONCLUSIONS

In vivo confocal microscopy reveals profound HSK-induced changes in the superficial epithelium, as demonstrated by increase in cell size, decrease in cell density, and squamous metaplasia. This study demonstrated that these changes correlate strongly with changes in corneal innervation.

Acute Herpetic Keratitis: What is the Role for Ganciclovir Ophthalmic Gel?

Herpes simplex keratitis (HSK) is a major cause of corneal blindness in the world. Following the primary infection, the virus enters into a latent phase. Recurrent infectious or immune keratitis cause structural damage to the cornea, scarring, and may lead to blindness. Several commercially available topical and oral antiviral drugs for HSK are currently available. However, toxicity and low patient compliance hamper their use in HSK. Further, oral antiviral drugs alone are not always effective in HSK. Thus, there had been a need for safe and effective topical antiviral agents against HSK. Systemic ganciclovir has been in use for the treatment of cytomegalovirus infections. Recently, topical ganciclovir has become available for use in patients with HSK. Ganciclovir 0.15% ophthalmic gel has been shown to be both safe and effective against viruses of the herpes family. Topical ganciclovir ophthalmic gel is well tolerated and does not cause significant toxic effects on the ocular surface. Several multicenter studies have revealed the potential role of ganciclovir ophthalmic gel in the treatment and prophylaxis of epithelial HSK. In this paper, we have reviewed the pharmacology, efficacy, side effects, and the role of ganciclovir ophthalmic gel 0.15% in the treatment of acute herpetic keratitis.

CD11c controls herpes simplex virus 1 responses to limit virus replication during primary infection

CD11c is expressed on the surface of dendritic cells (DCs) and is one of the main markers for identification of DCs. DCs are the effectors of central innate immune responses, but they also affect acquired immune responses to infection. However, how DCs influence the efficacy of adaptive immunity is poorly understood. Here, we show that CD11c(+) DCs negatively orchestrate both adaptive and innate immunity against herpes simplex virus type 1 (HSV-1) ocular infection. The effectiveness and quantity of virus-specific CD8(+) T cell responses are increased in CD11c-deficient animals. In addition, the levels of CD83, CD11b, alpha interferon (IFN-α), and IFN-β, but not IFN-γ, were significantly increased in CD11c-deficient animals. Higher levels of IFN-α, IFN-β, and CD8(+) T cells in the CD11c-deficient mice may have contributed to lower virus replication in the eye and trigeminal ganglia (TG) during the early period of infection than in wild-type mice. However, the absence of CD11c did not influence survival, severity of eye disease, or latency. Our studies provide for the first time evidence that CD11c expression may abrogate the ability to reduce primary virus replication in the eye and TG via higher activities of type 1 interferon and CD8(+) T cell responses.

Treatment of viral conjunctivitis with antiviral drugs

Viral conjunctivitis is one of the most common disorders observed in ophthalmic emergency departments, yet no established treatment exists. Lately, antiviral medications have been introduced into clinical practice; however, a systematic review focusing on their use and effectiveness in the treatment of viral conjunctivitis has not been previously reported. We systemically reviewed the literature to identify studies where antiviral drugs were used to treat viral conjunctivitis. Currently, aciclovir, trifluridine and valaciclovir are commonly used as antiviral agents to treat herpesvirus infections. Cidofovir has been used successfully to treat some cases of adenoviral conjunctivitis, although toxicity has also been reported. The use of other medications, such as idoxuridine, has been minimized in clinical practice due to their high toxicity. Interestingly, most of the antiviral drugs developed are used to treat herpesvirus infections, while less progress has been made in the field of adenoviral infections. For other viral causes of conjunctivitis, no effective remedy is currently available, and treatment focuses on the relief of symptoms. Caution should be exercised when coadministering other pharmacological agents, such as corticosteroids, because of emerging adverse effects.

Circulating herpes simplex type 1 (HSV-1)-specific CD8+ T cells do not access HSV-1 latently infected trigeminal ganglia

Background

Therapeutic vaccines can be designed to enhance existing T cell memory populations for increased protection against re-infection. In the case of herpes simplex virus type 1, recurrent disease results from reactivation of latent virus in sensory ganglia, which is controlled in part by a ganglia-resident HSV-specific memory CD8⁺ T cell population. Thus, an important goal of a therapeutic HSV-1 vaccine would be to enhance this population.

Methods

HSV-1-infected mice were treated with TAK-779 to block CCR5- and CXCR3-mediated CD8⁺ T cell migration during both acute and latent infections. Additionally, HSV-1-specific CD8⁺ T cells were transferred into HSV-1 latently infected mice to mimic the effect of a therapeutic vaccine, and their migration into trigeminal ganglia (TG) was traced during steady-state latency, or during recovery of the TG-resident memory CD8⁺ T cell population following stress-, and corticosterone-induced depletion and HSV-1 reactivation from latency. Bromodeoxy uridine (BrdU) incorporation measured cell proliferation in vivo.

Results

TAK-779 treatment during acute HSV-1 infection reduced the number of infiltrating CD8⁺ T cells but did not alter the number of viral genome copies. TAK-779 treatment during HSV latency did not affect the size of the TG-resident memory CD8⁺ T cell population. Transferred HSV-specific CD8⁺ T cells failed to access latently infected TG during steady-state latency, or during recovery of the TG resident HSV-specific CD8⁺ T cell population following exposure of latently infected mice to stress and corticosterone. Recovery of the HSV-specific CD8⁺ T cell population after stress and corticosterone treatment occurred with homeostatic levels of cell division and did not require CD4⁺ T cell help.

Conclusions

Our findings are consistent with the notion that the CD8⁺ T cells in latently infected TG are a tissue-resident memory (Trm) population that is maintained without replenishment from the periphery, and that when this population is disrupted, it recovers without proliferation or detectable recruitment of HSV-specific CD8⁺ T cells from the blood. The compartmentalization of the HSV-specific CD8⁺ memory T cell population in latently infected TG will complicate the design of therapeutic vaccines.

Prospects for Developing an Effective Vaccine Against Ocular Herpes Simplex Virus Infection

One of the hallmarks of herpes simplex virus (HSV) infection is the establishment of a lifelong latent infection accompanied by periods of recurrent disease. Primary HSV infections or repeated clinical recurrences do not elicit immune responses capable of completely preventing recurrences of endogenous virus. It is therefore questionable if vaccination approaches that seek to mimic the immune response to natural infection will reduce infection or disease due to an exogenous viral challenge. Approaches to the induction of protective responses by altering or enhancing both innate and adaptive immunity, using novel vaccines specifically tested in models of HSV infections of the eye, such as recombinant viral vaccine vectors and DNA vaccines, are detailed in this review.

Lymphoid-related CD11c+ CD8alpha+ dendritic cells are involved in enhancing herpes simplex virus type 1 latency

The mechanism(s) by which herpes simplex virus type 1 (HSV-1) latency is established in neurons is not known. In this study, we examined the effect of dendritic cells (DCs) on the level of HSV-1 latency in trigeminal ganglia (TGs) of ocularly infected BALB/c and C57BL/6 mice. We found that immunization of wild-type mice with FMS-like tyrosine kinase 3 ligand (Flt3L) DNA, which increases the number of DCs, increased the amount of latency in infected mice. Conversely, depletion of DCs was associated with reduced latency. Latency was also significantly reduced in Flt3L(-/-) and CD8(-/-) mice. Interestingly, immunization of Flt3L(-/-) but not CD8(-/-) mice with Flt3L DNA increased latency. Transfer experiments using DCs expanded ex vivo with Flt3L or granulocyte-macrophage colony-stimulating factor suggested that increased latency was associated with the presence of lymphoid-related (CD11c(+) CD8alpha(+)) DCs, while reduced latency was associated with myeloid-related (CD11c(+) CD8alpha(-)) DCs. Modulation of DC numbers by Flt3L DNA immunization or depletion did not alter acute virus replication in the eye or TG or eye disease in ocularly infected mice. Our results suggest that CD11c(+) CD8alpha(+) DCs directly or indirectly increase the amount of HSV-1 latency in mouse TGs.

Synthesis, metabolism and cellular permeability of enzymatically stable dipeptide prodrugs of acyclovir

The objective of this study was to synthesize and evaluate novel enzymatically stable dipeptide prodrugs for improved absorption of acyclovir. l-Valine-l-valine-acyclovir (LLACV), l-valine-d-valine-acyclovir (LDACV), d-valine-l-valine-acyclovir (DLACV) and d-valine-d-valine-acyclovir (DDACV) were successfully synthesized. The uptake and transport studies were conducted on a Caco-2 cell line. Buffer stability and metabolism of the prodrugs in Caco-2, rat intestine and liver homogenates were studied. Structure and purity of the all compounds were confirmed with LC-MS/MS and NMR spectroscopy. Uptake and transport of [(3)H] glycylsarcosine was inhibited by all prodrugs except DDACV. DLACV and DDACV exhibited no measurable degradation in Caco-2 homogenate. Except DDACV other three prodrugs were hydrolyzed in rat intestine and liver homogenates. The order of permeability across Caco-2 was LDACV>LLACV>DDACV>DLACV. A linear correlation between the amount of prodrug transported and over all permeability of acyclovir was established. This study shows that the incorporation of one d-valine in a dipeptide did not abolish its affinity towards peptide transporters (PEPT). Moreover, it enhanced enzymatic stability of prodrug to a certain extent depending on the position in a dipeptide conjugate. This strategy improved both the cellular permeability and the amount of intact prodrug transported which would enable targeting the nutrient transporters at blood ocular barrier (BOB).

Immunization with a replication-defective herpes simplex virus 2 mutant reduces herpes simplex virus 1 infection and prevents ocular disease

Ocular infections with herpes simplex virus 1 can lead to corneal scarring and blindness, with herpes keratitis being the major infectious cause of blindness. There is currently no clinically approved vaccine and nearly all developmental vaccines are targeted against HSV-2 and genital herpes. We tested the ability of an HSV-2 replication-defective virus, a genital herpes vaccine candidate, to protect against HSV-1 corneal infection. Immunization with HSV-2 dl5-29 reduced viral replication in the cornea, prevented ocular disease and reduced latent infection by the HSV-1 strain. Therefore, this HSV-2 replication-defective mutant strain may have applications for prevention of herpes keratitis and genital herpes due to HSV-1 infection.

Anterior Segment and External Ocular Disorders Associated with Human Immunodeficiency Virus Disease

The eye is a common site for complications of human immunodeficiency virus (HIV) infection. Although cytomegalovirus retinitis remains the most prevalent of the blinding ocular disorders that can occur in individuals with the acquired immunodeficiency syndrome (AIDS), several important HIV-associated disorders may involve the anterior segment, ocular surface, and adnexae. Some of these entities, such as Kaposi sarcoma, were well described, but uncommon, before the HIV epidemic. Others, like microsporidial keratoconjunctivitis, have presentations that differ between affected individuals with HIV disease and those from the general population who are immunocompetent. The treatment of many of these diseases is challenging because of host immunodeficiency. Survival after the diagnosis of AIDS has increased among individuals with HIV disease because of more effective antiretroviral therapies and improved prophylaxis against, and treatment of, opportunistic infections. This longer survival may lead to an increased prevalence of anterior segment and external ocular disorders. In addition, the evaluation and management of disorders such as blepharitis and dry eye, which were previously overshadowed by more severe, blinding disorders, may demand increased attention, as the general health of this population improves. Not all individuals infected with HIV receive potent antiretroviral therapy, however, because of socioeconomic or other factors, and others will be intolerant of these drugs or experience drug failure. Ophthalmologists must, therefore, still be aware of the ocular findings that develop in the setting of severe immunosuppression. This article reviews the spectrum of HIV-associated anterior segment and external ocular disorders, with recommendations for their evaluation and management.

Effects of the topical treatment with NSAIDs on corneal sensitivity and ocular surface of Sjögren's syndrome patients

AIM AND PURPOSE

To evaluate the effects of two NSAIDs on corneal sensitivity and ocular surface in Sjögren's syndrome (SS) patients.

METHODS

In all, 20 SS patients with epithelial corneal defects, were randomly divided into two groups: group 1 (10 females, age 35-63 years), treated with 0.1% indomethacin, one drop three times a day; group 2 (nine females, one male, age 38-65 years) treated with 0.1% diclofenac, at the same regimen. No systemic NSAIDs were allowed. Use of tear substitute was allowed. Corneal sensitivity, corneal staining, BUT, and ocular discomfort, were evaluated before and after 15, 30 days of treatment and 7 days after NSAID discontinuation. For statistical analysis, the Student's t-test and Mann-Whitney U test were used.

RESULTS

Both groups showed at day 30 a statistically significant reduction of corneal sensitivity (P<0.05), although the diclofenac-treated group showed a statistically significant lower sensitivity if compared to the indomethacin-treated group (P<0.05). Corneal fluorescein score showed a statistically significantly worst alteration in group 2, 7 days after the discontinuation of the therapy (P=0.02). The ocular discomfort score was statistically significantly reduced in both groups starting from day 15 (P<0.05).

DISCUSSION

The results indicate that NSAIDs can be useful in resolving symptoms of ocular discomfort in SS patients. However, they should be used with caution and under close monitoring, and the treatment should be promptly discontinued if corneal epithelial defects develop or worsen during treatment.

Recombinant herpes simplex virus type 1 (HSV-1) codelivering interleukin-12p35 as a molecular adjuvant enhances the protective immune response against ocular HSV-1 challenge

An important aspect of ocular herpes simplex virus type 1 (HSV-1) vaccine development is identification of an appropriate adjuvant capable of significantly reducing both virus replication in the eye and explant reactivation in trigeminal ganglia. We showed recently that a recombinant HSV-1 vaccine expressing interleukin-4 (IL-4) is more efficacious against ocular HSV-1 challenge than recombinant viruses expressing IL-2 or gamma interferon (IFN-gamma) (Y. Osorio and H. Ghiasi, J. Virol. 77:5774-5783, 2003). We have now constructed and compared recombinant HSV-1 viruses expressing IL-12p35 or IL-12p40 molecule with IL-4-expressing HSV-1 recombinant virus. BALB/c mice were immunized intraperitoneally with IL-12p35-, IL-12p40-, IL-12p35+IL-12p40-, or IL-4-expressing recombinant HSV-1 viruses. Controls included mice immunized with parental virus and mice immunized with the avirulent strain KOS. The efficacy of each vaccine in protecting against ocular challenge with HSV-1 was assessed in terms of survival, eye disease, virus replication in the eye, and explant reactivation. Neutralizing antibody titers, T-cell responses, and expression of 32 cytokines and chemokines were also evaluated. Mice immunized with recombinant HSV-1 expressing IL-12p35 exhibited the lowest virus replication in the eye, the most rapid virus clearance, and the lowest level of explant reactivation. The higher efficacy against ocular virus replication and explant reactivation correlated with higher neutralizing antibody titers, cytotoxic-T-lymphocyte activities, and IFN-gamma expression in recombinant HSV-1 expressing IL-12p35 compared to other vaccines. Mice immunized with both IL-12p35 and IL-12p40 had lower neutralizing antibody responses than mice immunized with IL-12p35 alone. Our results confirm that recombinant virus vaccines expressing cytokine genes can enhance the overall protection against infection, with the IL-12p35 vaccine being the most efficacious of those tested. Collectively, the results support the potential use of IL-12p35 as a vaccine adjuvant, without the toxicity-associated concerns of IL-12.

Involvement of CD8+ T-cells in exacerbation of corneal scarring in mice

PURPOSE

To determine the specific immune responses involved in the exacerbation of corneal scarring induced by HSV-1 in gK vaccinated mice.

MATERIALS AND METHODS

BALB/c mice were vaccinated with HSV-1 glycoprotein K (gK) and ocularly challenged with HSV-1. Infiltration into the cornea of T cells and macrophages was monitored by immunocytochemistry, and the effect of depletion of CD4+ T-cells, CD8+ T-cells, or macrophages on corneal scarring was determined.

RESULTS

Following ocular challenge, CD4+ and CD8+ T-cells and macrophages were more abundant in the corneas of gK-vaccinated mice than in the corneas of mock vaccinated mice. Depletion of CD8+ T-cells, but not of CD4+ T-cells or macrophages, reduced the severity of corneal scarring in gK-vaccinated mice.

CONCLUSIONS

We have shown that gK vaccination causes an overall increase in T cells and macrophages in the cornea after ocular HSV-1 challenge. The immunopathology induced by gK vaccination appears to be related to CD8+ T-cell activity, as depletion of these cells, but not other immune cells, reduced corneal scarring.

Impression Cytology of Herpetic Simplex Keratitis in Rabbits

PURPOSE

To use impression cytology to examine the structural changes in corneal epithelial cells infected with the herpes simplex virus in rabbit eyes.

METHODS

Corneal surfaces of 7 rabbits were scratched using a 25-gauge needle. Herpes simplex virus (type 1, Kos strain) was inoculated to the injured cornea. As the corneal diseases were observed using slit lamp biomicroscopy, impression cytology was performed for 18 days after inoculation. Specimens were stained with hematoxylin-eosin and examined using optical microscopy.

RESULTS

Corneal lesions consisted mainly of round epithelial cells, inflammatory cells, ballooning cells, multinucleated giant cells, and various inclusion bodies. Over time, the comeal epithelial cells peeled away as a result of corneal edema in the comeal lesions. Dendritic lesions were also observed. In the recovery phase, the number of detached cells and infiltrated inflammatory cells decreased.

CONCLUSIONS

It was presumed that dendritic lesions might have been formed at the scratched cornea region, thereby aggravating the epithelial cells falling off as a result of the infiltration of inflammatory cells. These cytopathologic effects occur in experimental herpes simplex keratitis.

Corneal epithelial cells and stromal keratocytes efficently produce CC chemokine-ligand 20 (CCL20) and attract cells expressing its receptor CCR6 in mouse herpetic stromal keratitis

PURPOSE

CC chemokine-ligand 20 (CCL20) is known to be selectively expressed by surface-lining mucosal epithelial cells and skin epidermal keratinocytes and to attract cells such as immature dendritic cells and effector T cells via CCR6. This study evaluated the ability of corneal epithelial cells and stromal keratocytes to produce CCL20 in vitro and in vivo.

METHODS

Human corneal epithelial cells (HCE) and corneal keratocytes (HCK) were treated without or with various cytokines and expression of CCL20 mRNA and secreion of its protein were evaluated by RT-PCR and ELISA. Induction of CCL20 mRNA in HCE and HCK was also examined upon in vitro infection with HSV-1. Using a mouse model of herpetic stromal keratitis (HSK), induction of CCL20 expression and accumulation of cells expressing CCR6 were evaluated by RT-PCR and immunohistochemistry.

RESULTS

Not only corneal epithelial cells but also stromal keratocytes efficiently expressed CCL20 mRNA and protein upon stimulation with IL-1beta and TNF-alpha. In vitro infection with HSV-1 also induced CCL20 mRNA in both types of cells. In a mouse herpetic stromal keratitis model, prominent accumulation of CCL20 and CCR6 mRNA was revealed in HSV-1-infected corneas. Furthermore, immunohistochemistry demonstrated production of CCL20 by corneal epithelial cells as well as stromal keratocytes and stromal infiltration of DEC205+ dendritic cells, CD4+ T cells and CD8+ T cells. Double staining revealed that CCR6-expressing cells were mostly MHC class II+ dendritic cells.

CONCLUSIONS

Not only epithelial cells but also stromal keratocytes are efficient producers of CCL20 in the cornea and recruit CCR6-expressing cells such as dendritic cells into inflamed cornea.

Suppression of autoimmune disease after vaccination with autoreactive T cells that express Qa-1 peptide complexes

The ability of autoreactive T cells to provoke autoimmune disease is well documented. The finding that immunization with attenuated autoreactive T cells (T cell vaccination, or TCV) can induce T cell-dependent inhibition of autoimmune responses has opened the possibility that regulatory T cells may be harnessed to inhibit autoimmune disease. Progress in the clinical application of TCV, however, has been slow, in part because the underlying mechanism has remained clouded in uncertainty. We have investigated the molecular basis of TCV-induced disease resistance in two murine models of autoimmunity: herpes simplex virus-1 (KOS strain)-induced herpes stromal keratitis and murine autoimmune diabetes in non-obese diabetic (NOD) mice. We find that the therapeutic effects of TCV depend on activation of suppressive CD8 cells that specifically recognize Qa-1-bound peptides expressed by autoreactive CD4 cells. We clarify the molecular interaction between Qa-1 and self peptides that generates biologically active ligands capable of both inducing suppressive CD8 cells and targeting them to autoreactive CD4 cells. These studies suggest that vaccination with peptide-pulsed cells bearing the human equivalent of murine Qa-1 (HLA-E) may represent a convenient and effective clinical approach to cellular therapy of autoimmune disease.

Prescribing trends in infectious keratitis: a survey of New Zealand ophthalmologists

PURPOSE

To obtain an overview of the treatment of infectious diseases of the cornea by New Zealand ophthalmologists and to analyse the data in the context of evidence-based treatment recommendations.

METHODS

A questionnaire was sent to all New Zealand ophthalmologists. It comprised 23 multiple-choice questions pertaining to the characteristics of the respondents, the nature of their practice and their prescribing preferences in infectious conjunctivitis and keratitis.

RESULTS

Of the 93 ophthalmologists surveyed, 80.6% returned the questionnaire. Of those in clinical practice, 91.4% regularly treated patients with corneal disease. A subspecialty interest in cornea was stated by 12.5% of these. This paper reports observations for adenoviral conjunctivitis and adenoviral, Herpes simplex, varicella zoster, bacterial, acanthamoebal and fungal keratitis. In some conditions prescribing practice varied dramatically, such as in adenoviral conjunctivitis where 50% of respondents prescribed a corticosteroid and 51.6% an antibiotic, whereas 37.5% prescribed only lubrication or no topical treatment. In other conditions there was a high degree of agreement between ophthalmologists; indeed, all ophthalmologists treated Herpes simplex dendritic keratitis with topical acyclovir. No statistically significant differences in prescribing habits were identified between subspecialist and non-subspecialist groups, although some important clinical differences emerged. There were occasional marked differences in response when the age group of respondents was considered, particularly in relation to the management of adenoviral infections and bacterial keratitis.

CONCLUSIONS

The findings of this survey suggest that the majority of New Zealand ophthalmologists generally follow international guidelines for the management of infectious keratitis. The identified variations in management provide a foundation for informed clinical debate and the development of treatment guidelines, in line with evidence-based recommendations.