Impact of Adherence (Compliance) to Oral Acyclovir Prophylaxis in the Recurrence of Herpetic Keratitis: Long-Term Results From a Pediatric Cohort.

PURPOSE: To evaluate the long-term role of adherence to oral acyclovir prophylaxis in reducing the risk for recurrent herpes simplex virus keratitis (HSK) in children. METHODS: A retrospective cohort study was performed including all pediatric patients 16 years or younger) with their first HSK diagnosis and treatment at our center. Children were started on a standardized oral acyclovir prophylactic regimen after the acute phase. Adherence to prophylaxis was assessed monthly through parent interviews. The possible association between any recurrence (not only the first) and exposure to acyclovir prophylaxis was evaluated using random-effects multivariate logistic regression. RESULTS: A total of 20 eyes of 17 patients (8 boys and 9 girls) were included. The mean follow-up time was 3.5 years. Adherence to acyclovir prophylaxis was registered in 100% of patients with no recurrences and in 36.4% of patients with 1 or more recurrences (P = 0.035). All other tested variables (time of follow-up, sex, age, infectious diseases, underlying hematological diseases, eye, and HSK type) did not differ between the 2 groups. The multivariate model confirmed the lower risk for recurrence in patients who were compliant to therapy (adjusted odds ratio 0.04, 95% confidence intervals 0.00-0.42, P = 0.008). No adverse effects were recorded during follow-up. CONCLUSIONS: Oral acyclovir prophylaxis is a safe and an effective medical treatment for recurrent HSK and its long-term efficacy is associated with compliance to the therapy.

Role of TH17 Responses in Increasing Herpetic Keratitis in the Eyes of Mice Infected with HSV-1.

Purpose: TH17 cells play an important role in host defense and autoimmunity yet very little is known about the role of IL17 in herpes simplex virus (HSV)-1 infectivity. To better understand the relationship between IL17 and HSV-1 infection, we assessed the relative impact of IL17A-deficiency and deficiency of its receptors on HSV-1 responses in vivo. Methods: We generated IL17RA-/- and IL17RA-/-RC-/- mice in-house and infected them along with IL17A-/- and IL17RC-/- mice in the eyes with 2 × 105 PFU/eye of wild type (WT) HSV-1 strain McKrae. WT C57BL/6 mice were used as control. Virus replication in the eye, survival, corneal scarring (CS), angiogenesis, levels of latency-reactivation, and levels of CD8 and exhaustion markers (PD1, TIM3, LAG3, CTLA4, CD244, and CD39) in the trigeminal ganglia (TG) of infected mice were determined on day 28 postinfection. Results: No significant differences in virus replication in the eye, survival, latency, reactivation, and exhaustion markers were detected among IL17A-/-, IL17RA-/-, IL17RC-/-, IL17RA-/-RC-/-, and WT mice. However, mice lacking IL17 had significantly less CS and angiogenesis than WT mice. In addition, angiogenesis levels in the absence of IL17RC and irrespective of the absence of IL17RA were significantly less than in IL17A- or IL17RA-deficient mice. Conclusions: Our results suggest that the absence of IL17 protects against HSV-1-induced eye disease, but has no role in protecting against virus replication, latency, or reactivation. In addition, our data provide rationale for blocking IL17RC function rather than IL17A or IL17RA function as a key driver of HSV-1-induced eye disease.

[Research progress of corneal neovascularization in herpes stromal keratitis].

Herpes simplex virus (HSV) infection can cause inflammatory reactions and angiogenesis of the cornea, which significantly reduce corneal transparency. Herpes stromal keratitis (HSK) is an immune mediated disease caused by HSV infection, and is associated with inflammation and angiogenesis of the cornea. It is difficult to control HSK therapeutically. Repeated episodes of HSK can result in chronic inflammatory disease in the corneal stroma. Neovascularization plays a key role in the pathogenesis of HSK, so inhibiting the angiogenesis will help to control HSK disease. In this review, the pathomechanism of HSK is described. The roles of multiple cytokines and soluble mediators in corneal vascularization are discussed, and the potential ways of preventing and controlling corneal vascularization induced by HSK are summarized. (Chin J Ophthalmol, 2019, 55:956-960).

Ocular manifestations of herpes simplex virus.

PURPOSE OF REVIEW: To review ocular manifestations and complications of herpes simplex virus (HSV) and discuss recent advancements in diagnostic and treatment strategy. RECENT FINDINGS: In-vivo confocal microscopy has expanded our understanding of corneal nerve degeneration, corneal dendritic cell activity, and changes in biomechanical properties in HSV keratitis. Although currently available only as a research tool, metagenomic deep sequencing has the potential to improve diagnostic accuracy beyond the well established PCR technology, especially in atypical cases. Development of an HSV vaccine has shown some encouraging results in a murine model. New treatment options for neurotrophic cornea offer promise, specifically cenegermin nerve growth factor. SUMMARY: Ocular herpes simplex infection and its complications continue to cause significant visual burden and decreased quality of life. Familiarity with its clinical features, wider adoption of viral PCR diagnostic technology, and recognition of the need for long-term maintenance medications for recurrent or chronic cases form the basis for effective management. Metagenomic deep sequencing, the development of a herpes vaccine, and cenegermin nerve growth factor offer promise as diagnostic, preventive, and therapeutic options, respectively.

Development of lacrimal gland inflammation in the mouse model of herpes stromal keratitis.

Herpes stromal keratitis (HSK) is a chronic immunoinflammatory condition which develops in response to recurrent herpes simplex virus-1 (HSV-1) infection of the cornea. Patients with HSK often demonstrate the concurrence of corneal desiccation and the loss of blink reflex. However, the relationship between severity of HSK, level of basal tears and inflammation of the lacrimal gland is mostly unexplored. In this study, we compared these variables in extraorbital lacrimal gland (EoLG) after corneal HSV-1 infection in the C57BL/6J mouse model. Our results showed a significant reduction in the volume of tears in infected eyes during the development of HSK. Extensive architectural damage to EoLG, presumably caused by a massive influx of interferon-gamma secreting T cells, was observed during clinical disease period of HSK. A positive correlation between the decrease in tear volume, severity of HSK and the damage to EoLG were evident in infected mice. The presence of infectious virus measured in EoLG during pre-clinical, but not clinical disease period of HSK, suggested that viral cytopathic effects are not the major contributors of extensive damage seen in EoLG. Furthermore, topical administration of lacritin peptide delayed but did not prevent the decrease in tears in HSV-1 infected mice, and had no significant effect in either reducing the severity of HSK or T cell infiltration in EoLG of infected mice. Together, our results showed an interplay between the severity of HSK, inflammation of EoLG, and the reduced level of tears after corneal HSV-1 infection.

Risk factors influencing survival of acellular porcine corneal stroma in infectious keratitis: a prospective clinical study.

BACKGROUND: A worldwide lack of donor corneas demands the bioengineered corneas be developed as an alternative. The primary objective of the current study was to evaluate the efficacy of acellular porcine corneal stroma (APCS) transplantation in various types of infectious keratitis and identify risk factors that may increase APCS graft failure. METHODS: In this prospective interventional study, 39 patients with progressive infectious keratitis underwent therapeutic lamellar keratoplasty using APCS and were followed up for 12 months. Data collected for analysis included preoperative characteristics, visual acuity, graft survival and complications. Graft survival was evaluated by the Kaplan-Meier method and compared with the log-rank test. RESULTS: The percentage of eyes that had a visual acuity of 20/40 or better increased from 10.3% preoperatively to 51.2% at 12 months postoperatively. Twelve patients (30.8%) experienced graft failure within the follow-up period. The primary reasons given for graft failure was noninfectious graft melting (n = 5), and the other causes included recurrence of primary infection (n = 4) and extensive graft neovascularization (n = 3). No graft rejection was observed during the follow-up period. A higher relative risk (RR) of graft failure was associated with herpetic keratitis (RR = 8.0, P = 0.046) and graft size larger than 8 mm (RR = 6.5, P < 0.001). CONCLUSIONS: APCS transplantation is an alternative treatment option for eyes with medically unresponsive infectious keratitis. Despite the efficacy of therapeutic lamellar keratoplasty with APCS, to achieve a good prognosis, restriction of surgical indications, careful selection of patients and postoperative management must be emphasized. Trial registration Prospective Study of Deep Anterior Lamellar Keratoplasty Using Acellular Porcine Cornea, NCT03105466. Registered 31 August 2016, ClinicalTrails.gov.

PEDF Reduces the Severity of Herpetic Simplex Keratitis in Mice.

Purpose: The purpose of this study was to explore the effects of pigment epithelium derived factor (PEDF) and PEDF-derived peptides Mer44 and Mer34 on the severity of herpetic simplex keratitis (HSK) in mice. Methods: Adult C57BL/6 mice were infected ocularly with the herpes simplex virus type 1 (HSV-1, McKrae strain) and injected subconjunctivally with PEDF, Mer44, or Mer34. Corneal nerve degeneration, neovascularization, sensitivity, neutrophils, macrophages and CD4+ T-cell infiltration, virus contents, and expressions of VEGF, PEDF, and proinflammatory factors were evaluated during acute period. The direct inhibitory effect of PEDF on HSV-1 replication was further evaluated in cultured monkey Vero cells. Results: Following HSV-1 infection, corneal PEDF expression decreased at 3 and 7 days postinfection (dpi) but increased at 15 dpi, and returned to the similar level of normal mice at 45 dpi, which was accompanied with the progress of corneal nerve degeneration and neovascularization. Exogenous PEDF application attenuated corneal nerve degeneration and neovascularization and improved the impaired corneal sensitivity. Moreover, PEDF attenuated the neutrophils, but not macrophage or CD4+ T-cell infiltration, with the reduced expressions of IL-1ß, IL-6, TNF-α, and VEGF. In addition, PEDF inhibited the replication of HSV-1 both in vitro and in mice. Mer44 attenuated corneal nerve degeneration more significantly than Mer34, whereas Mer34 inhibited corneal neovascularization. Conclusions: PEDF and its derived peptides reduce the severity of herpetic simplex keratitis in mice, representing the potential therapeutic approach to control HSK lesions.

The Association between Diabetes and Herpes Simplex Eye Disease.

PURPOSE: To evaluate the association between diabetes mellitus (DM) and presence and severity of Herpes simplex eye disease (HSED). METHODS: We conducted two sub-studies. We included the patients seen on the Cornea Service of the Wills Eye Hospital from January 2008 to August 2012. Study 1 included 541 patients with HSED and 3226 controls. Study 2 involved 40 diabetic and 120 non-diabetic ocular surface HSED patients. Severity of ocular surface HSED was graded as mild, moderate, or severe, based on best-corrected visual acuity (BCVA). Patients were excluded if they had fewer than two office visits or had non-Herpes simplex-related vision-threatening conditions. Diabetes was graded as: diet group (DM controlled with diet), oral group (DM controlled with oral medications), and insulin group (DM control required insulin). RESULTS: Five of 541 (0.93%) HSED patients had type 1 DM, similar to 19/3246 (0.59%) controls (p = 0.375); 48 of 541 (8.88%) HSED patients had type 2 DM, similar to 287/3246 (8.84%) controls (p = 0.981). Using multinomial logistic regression analyses, the probability/risk of being in the severe ocular surface HSED group as opposed to the mild ocular surface HSED group were not statistically significantly different between DM patients and those without DM (p = 0.120; OR, 1.900; 95% CI, 0.846-4.266). CONCLUSIONS: There may not be a positive association between type 2 DM and HSED.

Dendritic cells in the cornea during Herpes simplex viral infection and inflammation.

Herpes simplex keratitis is commonly caused by Herpes simplex virus type 1, which primarily infects eyelids, corneas, or conjunctiva. Herpes simplex virus type 1-through sophisticated interactions with dendritic cells (DCs), a type of antigen-presenting cell)-initiates proinflammatory responses in the cornea. Corneas were once thought to be an immune-privileged region; however, with the recent discovery of DCs that reside in the cornea, this long-held conjecture has been overturned. Therefore, evaluating the clinical, preclinical, and cell-based studies that investigate the roles of DCs in corneas infected with Herpes simplex virus is critical. With in vivo confocal microscopy, animal models, and cell culture experiments, we may further the understanding of the sophisticated interactions of Herpes simplex virus with DCs in the cornea and the molecular mechanism associated with it. It has been shown that specific differentiation of DCs using immunohistochemistry, flow cytometry, and polymerase chain reaction analysis in both human and mice tissues and viral tissue infections are integral to increasing understanding. As for in vivo confocal microscopy, it holds promise as it is the least invasive and a real-time investigation. These tools will facilitate the discovery of various targets to develop new treatments.

Impact of herpetic stromal immune keratitis in corneal biomechanics and innervation.

PURPOSE: To study corneal innervation in eyes with history of herpetic keratitis and its correlation with corneal sensitivity and biomechanical properties. METHODS: A total of 56 eyes were included, of which 16 had a history of unilateral immune stromal herpetic keratitis, 16 were their contralateral eyes, and 20 were healthy controls. Structural analysis of corneal nerve plexus was performed by confocal microscopy. Biomechanical properties were measured with the Ocular Response Analyzer. Corneal sensitivity was assessed by contact (Cochet-Bonnet) and non-contact (Belmonte) esthesiometry. RESULTS: The eyes with a history of herpetic keratitis had reduced sensitivity for mechanical stimuli when compared to healthy eyes (1441.88 ± 83 ml/min vs. 67.9 ± 7.86 ml/min). Nerve fiber density in the corneas with a history of herpetic disease was lower (4.13 ± 2.19 U/image) than in the contralateral eyes (7.44 ± 2.9 U/image, p value = 0.01) and than in healthy controls (10.35 ± 2.01, p value < 0.0001). The best structural and functional correlation was established between the total length of nerves per section and mechanic threshold assessed by Belmonte esthesiometer (Coef. -0.58 p value < 0.0001) and between total length of nerves and corneal resistance factor (CRF) (Coef. -0.64, p value < 0.0001). CONCLUSIONS: The corneal sensitivity impairment in eyes with immune stromal herpetic keratitis can be explained by the loss of nerve fibers. Biomechanical corneal properties are affected as well. Corneal hysteresis (CH) and CRF are lower for the eyes with a history of herpetic keratitis, and also for the contralateral eye when compared to healthy controls.

Inferred father-to-son transmission of herpes simplex virus results in near-perfect preservation of viral genome identity and in vivo phenotypes.

High throughout sequencing has provided an unprecedented view of the circulating diversity of all classes of human herpesviruses. For herpes simplex virus 1 (HSV-1), we and others have previously published data demonstrating sequence diversity between hosts. However the extent of variation during transmission events, or in one host over years of chronic infection, remain unknown. Here we present an initial example of full characterization of viruses isolated from a father to son transmission event. The likely occasion of transmission occurred 17 years before the strains were isolated, enabling a first view of the degree of virus conservation after decades of recurrences, including transmission and adaptation to a new host. We have characterized the pathogenicity of these strains in a mouse ocular model of infection, and sequenced the full viral genomes. Surprisingly, we find that these two viruses have preserved their phenotype and genotype nearly perfectly during inferred transmission from father to son, and during nearly two decades of episodes of recurrent disease in each human host. Given the close genetic relationship of these two hosts, it remains to be seen whether or not this conservation of sequence will occur during non-familial transmission events.

A Novel Entity of Corneal Diseases with Irregular Posterior Corneal Surfaces: Concept and Clinical Relevance.

Various corneal diseases, such as hereditary corneal dystrophies, corneal infection, and bullous keratopathy, cause corneal opacity, scarring, and edema, leading to severely decreased visual acuity and loss of vision. These diseases were regarded as corneal opacity diseases, and the decreased visual acuity was considered to be predominantly caused by corneal opacity. The influence of corneal irregular astigmatism on vision has been poorly understood to date, mainly because accurate quantification of irregular astigmatism has been technically challenging. We have performed detailed analyses of the corneal higher-order aberrations (HOAs) of the anterior and posterior surfaces and total cornea in corneal diseases, using an anterior segment imaging system combined with a ray-tracing method. Subsequently, we conducted correlation analyses between corneal HOAs and visual acuities and characterized the typical HOA patterns in the corneal diseases. Our recent studies demonstrated that corneal HOAs directly degrade visual acuity in eyes with mild-to-moderate corneal opacities, such as corneal dystrophies, corneal scarring, and bullous keratopathy. The findings also suggested that correction of corneal HOAs using rigid gas-permeable contact lenses is effective in eyes with a smooth posterior surface and useful in certain patients with corneal scarring to some extent. Our data will be useful for decision making regarding surgical interventions, based on the amount of corneal HOAs. Our results further indicate the clinical relevance of irregular astigmatism in the posterior surfaces in assessing the visual function of eyes with various corneal diseases.

Self-Retained Amniotic Membrane Combined With Antiviral Therapy for Herpetic Epithelial Keratitis.

PURPOSE: To evaluate the therapeutic benefit of self-retained cryopreserved amniotic membrane in conjunction with oral antiviral therapy in herpetic epithelial keratitis. METHODS: Retrospective review of 4 patients with primary (1 eye) and recurrent (3 eyes) unilateral herpetic epithelial keratitis treated with cryopreserved amniotic membrane through the placement of the PROKERA Slim (PKS) (Bio-Tissue, Inc) in conjunction with oral acyclovir. Their symptoms, conjunctival inflammation, corneal staining, and visual acuity were compared before and after treatment. RESULTS: Herpetic epithelial keratitis presented as dendritic (3 eyes) and geographic (1 eye) epithelial lesions. After epithelial debridement and placement of the PKS for 5 ± 3.7 days, all patients reported significant relief of symptoms, rapid corneal epithelialization, and reduction of ocular surface inflammation. The visual acuity was also improved in all eyes from 0.7 ± 0.7 to 0.4 ± 0.7 logarithm of the minimum angle of resolution (P = 0.2). They remained symptom-free during a follow-up period of 2.7 to 50.8 (20.3 ± 21.7) months. CONCLUSIONS: The PKS in conjunction with oral acyclovir facilitates the ease of early intervention to accelerate restoration of a normal corneal epithelium in herpetic epithelial keratitis.

The Plasticity and Stability of Regulatory T Cells during Viral-Induced Inflammatory Lesions.

Ocular infection with HSV causes a chronic T cell-mediated inflammatory lesion in the cornea. Lesion severity is affected by the balance of different CD4 T cell subsets, with greater severity occurring when the activity of regulatory T cells (Tregs) is compromised. In this study, fate-mapping mice were used to assess the stability of Treg function in ocular lesions. We show that cells that were once Foxp3+ functional Tregs may lose Foxp3 and become Th1 cells that could contribute to lesion expression. The instability primarily occurred with IL-2Rlo Tregs and was shown, in part, to be the consequence of exposure to IL-12. Lastly, in vitro-generated induced Tregs (iTregs) were shown to be highly plastic and capable of inducing stromal keratitis when adoptively transferred into Rag1-/- mice, with 95% of iTregs converting into ex-Tregs in the cornea. This plasticity of iTregs could be prevented when they were generated in the presence of vitamin C and retinoic acid. Importantly, adoptive transfer of these stabilized iTregs to HSV-1-infected mice prevented the development of stromal keratitis lesions more effectively than did control iTregs. Our results demonstrate that CD25lo Treg and iTreg instability occurs during a viral immunoinflammatory lesion and that its control may help to avoid lesion chronicity.

PEDF plus DHA modulate inflammation and stimulate nerve regeneration after HSV-1 infection.

Herpes simplex virus type-1 (HSV-1) infection leads to impaired corneal sensation and, in severe cases, to corneal ulceration, melting and perforation. Here, we explore the potential therapeutic action of pigment epithelial-derived factor (PEDF) plus docosahexaenoic acid (DHA) on corneal inflammation and nerve regeneration following HSV-1 infection. Rabbits inoculated with 100,000 PFU/eye of HSV-1 strain 17Syn+ were treated with PEDF + DHA or vehicle. PEDF + DHA treatment resulted in a biphasic immune response with stronger infiltration of CD4+T cells, neutrophils and macrophages at 7-days post-treatment (p.t.) that was significantly decreased by 14 days, compared to the vehicle-treated group. Screening of 14 immune-related genes by q-PCR showed that treatment induced higher expression of IFN-γ and CCL20 and inhibition of IL-18 by 7 days in the cornea. PEDF + DHA-treated animals developed less dendritic corneal lesions, opacity and neovascularization. Corneal nerve density increased at 12-weeks p.t. with functional recovery of corneal sensation. Treatment with PEDF + DHA that was postponed by 3 weeks also showed increased nerve density when compared to vehicle. Our data demonstrate that PEDF + DHA promotes resolution of the inflammatory response to the virus and, most importantly, induces regeneration of damaged corneal nerves vital for maintaining ocular surface homeostasis.

Subclinical Herpes Simplex Virus Type 1 Infections Provide Site-Specific Resistance to an Unrelated Pathogen.

HSV-1 infections of the cornea range in severity from minor transient discomfort to the blinding disease herpes stromal keratitis, yet most patients experience a single episode of epithelial keratitis followed by re-establishment of a clear cornea. We asked whether a single transient episode of HSV-1 epithelial keratitis causes long-term changes in the corneal microenvironment that influence immune responses to subsequent corneal infection or trauma. We showed that C57BL/6 mouse corneas infected with HSV-1 KOS, which induces transient herpes epithelial keratitis without herpes stromal keratitis sequelae, possessed a significant leukocytic infiltrate composed primarily of CD4+ T cells and macrophages along with elevated chemokines and cytokines that persisted without loss of corneal clarity (subclinical inflammation). Chemokine and cytokine expression was CD4+ T cell dependent, in that their production was significantly reduced by systemic CD4+ T cell depletion starting before infection, although short-term (3-d) local CD4+ T cell depletion postinfection did not influence chemokine levels in cornea. Corneas with subclinical inflammation developed significantly greater trauma-induced inflammation when they were recipients of syngeneic corneal transplants but also exhibited significantly increased resistance to infections by unrelated pathogens, such as pseudorabies virus. The resistance to pseudorabies virus was CD4+ T cell dependent, because it was eliminated by local CD4+ T cell depletion from the cornea. We conclude that transient HSV-1 corneal infections cause long-term alterations of the corneal microenvironment that provide CD4-dependent innate resistance to subsequent infections by antigenically unrelated pathogens.

Bilateral tear film alterations in patients with unilateral quiescent herpes simplex keratitis.

PURPOSE: To evaluate bilateral tear function and corneal sensitivity in patients with unilateral quiescent herpes simplex keratitis (HSK) and determine the correlation between corneal sensitivity and tear secretion in both eyes. METHODS: Thirty-five patients diagnosed with unilateral quiescent HSK and 35 heathy controls were included in this study. Bilateral tear osmolarity, Schirmer's test, the tear break-up time (TBUT) and corneal sensitivity were measured in all participants. RESULTS: In the HSK group, both eyes demonstrated a significant increase in tear osmolarity, and a decrease in Schirmer's test and the TBUT compared with healthy controls (All p < 0.001). The bilateral tear osmolarity and Schirmer's test were similar, but the TBUT (4.9 ± 2.1 versus 7.4 ± 2.0 second; p < 0.001) and corneal sensitivity (35.1 ± 1.9 versus 54.3 ± 0.8 mm; p < 0.001) were significantly lower in the affected eyes. The bilateral tear osmolarity, Schirmer's test and the TBUT were significantly correlated with corneal sensitivity of the affected eye (All p < 0.001). When corneal sensitivity of the unaffected eye was treated as a control variable, tear osmolarity (R = -0.626, p < 0.001), Schirmer's test (R = 0.739, p < 0.001) and the TBUT (R = 0.691, p < 0.001) of the unaffected eyes were still significantly correlated with the corneal sensitivity of the affected eyes. CONCLUSIONS: Unilateral quiescent HSK causes bilateral tear impairment, which depends on the loss of corneal sensitivity in the affected eye. In the affected eye with severe corneal sensitivity loss, bilateral dry eye occurred.

Loss of Neurokinin-1 Receptor Alters Ocular Surface Homeostasis and Promotes an Early Development of Herpes Stromal Keratitis.

Substance P neuropeptide and its receptor, neurokinin-1 receptor (NK1R), are reported to present on the ocular surface. In this study, mice lacking functional NK1R exhibited an excessive desquamation of apical corneal epithelial cells in association with an increased epithelial cell proliferation and increased epithelial cell density, but decreased epithelial cell size. The lack of NK1R also resulted in decreased density of corneal nerves, corneal epithelial dendritic cells (DCs), and a reduced volume of basal tears. Interestingly, massive accumulation of CD11c+CD11b+ conventional DCs was noted in the bulbar conjunctiva and near the limbal area of corneas from NK1R-/- mice. After ocular HSV-1 infection, the number of conventional DCs and neutrophils infiltrating the infected corneas was significantly higher in NK1R-/- than C57BL/6J mice. This was associated with an increased viral load in infected corneas of NK1R-/- mice. As a result, the number of IFN-γ-secreting virus-specific CD4 T cells in the draining lymph nodes of NK1R-/- mice was much higher than in infected C57BL/6J mice. An increased number of CD4 T cells and mature neutrophils (CD11b+Ly6ghigh) in the inflamed corneas of NK1R-/- mice was associated with an early development of severe herpes stromal keratitis. Collectively, our results show that the altered corneal biology of uninfected NK1R-/- mice along with an enhanced immunological response after ocular HSV-1 infection causes an early development of herpes stromal keratitis in NK1R-/- mice.

Corneal Higher-Order Aberrations in Herpes Simplex Keratitis.

PURPOSE: To evaluate corneal higher-order aberrations (HOAs) in eyes with corneal scars due to herpes simplex keratitis (HSK). METHODS: Forty-four eyes of 41 consecutive patients who were diagnosed with corneal scars due to HSK and 18 control eyes were included. HOAs of the anterior and posterior surfaces and the total cornea were analyzed using anterior segment optical coherence tomography. Corneal opacity grades were assigned on the basis of slit-lamp examinations. RESULTS: HOAs within a 4-mm diameter were significantly larger in eyes with HSK (anterior surface, 1.01 ± 1.18 µm; posterior surface, 0.25 ± 0.24; total cornea, 1.00 ± 1.00) compared with controls (0.10 ± 0.02, 0.02 ± 0.00, and 0.09 ± 0.01, respectively; all P < 0.001). HOAs within a 6-mm diameter were significantly larger in eyes with HSK (anterior surface, 1.87 ± 1.75; posterior surface, 0.42 ± 0.44; total cornea, 1.85 ± 1.46) compared with controls (0.19 ± 0.04, 0.06 ± 0.01, and 0.17 ± 0.03, respectively; all, P < 0.001). The logarithm of the minimum angle of resolution (logMAR) decreased with the corneal opacity score (0.42 ± 0.61 in grade 1, 1.30 ± 0.96 in grade 2, and 1.58 ± 0.90 in grade 3). LogMAR was significantly correlated with HOAs (R = 0.65, P < 0.0001). HOAs of the posterior surface increased from 0.15 ± 0.15 in grade 1 to 0.37 ± 0.33 in grade 3 (P = 0.005), whereas there was no difference in HOAs of the anterior surface and the total cornea among the different corneal opacity grades. CONCLUSIONS: Increased HOAs of the anterior and posterior surfaces occur in eyes with corneal opacity due to HSK. Larger corneal HOAs are associated with poorer visual acuity.

A Central Role for Sympathetic Nerves in Herpes Stromal Keratitis in Mice.

PURPOSE: Herpes simplex virus type 1 (HSV-1) is a neurotrophic virus that can cause herpes stromal keratitis (HSK), a severe corneal inflammation that can lead to corneal scarring and blindness. This study identified neurologic changes that occur in HSV-1-infected corneas and related them to HSV-1-induced immunopathology. METHODS: Corneas of BALB/c and C57BL/6 mice were infected with HSV-1 strains that induce HSK. Changes in sensory nerves were identified by immunofluorescence staining of sensory and sympathetic nerves for substance P (SP) and tyrosine hydroxylase (TH), respectively, and confocal microscopic examination. Some mice received superior cervical ganglionectomy (SCGx) to eliminate sympathetic nerves from the cornea. RESULTS: Normal corneas exclusively expressed sensory nerves that entered the stroma as large nerve stalks, branched to form a plexus at the epithelial/stromal interface, and extended termini into the epithelium. These nerves completely retracted from the infected cornea and were replaced by sympathetic nerves that sprouted extensively to hyperinnervate the corneal stroma but failed to form a plexus or extend termini into the epithelium. The hyperinnervating nerves expressed the sympathetic nerve marker TH and their invasion was blocked by performing SCGx. Moreover, the corneal opacity and neovascularization that normally characterizes HSK in this mouse model were largely abrogated by SCGx. Sensory nerves reinnervated infected corneas following SCGx, reformed a nerve plexus, and extended termini into the epithelium resulting in recovery of corneal sensitivity. CONCLUSIONS: Sympathetic nerves have a central role in HSK in mice, preventing reinnervation by sensory nerves and promoting severe and persistent corneal inflammation.