A microscopic study of herpes simplex virus retinopathy in mice.

ICR white mice were inoculated with herpes simplex virus (HSV) type I in the anterior chamber of one eye. Animals were killed at intervals of 2, 4, 6, 8, and 10 days and both eyes were obtained for light and electron microscopic study of retinal changes. HSV retinopathy developed in 42 (91%) of 46 inoculated eyes. Fourteen (88%) of sixteen noninoculated eyes examined after the sixth postinoculation day developed HSV retinopathy. The earliest signs of retinopathy in the inoculated eye were peripheral retinal vasculitis and inflammatory cells throughout the nerve fiber layer on day 2. No virus was found in retinal tissue until day 4, at which time disruption of outer retinal layers (outer nuclear layer and layer of rods and cones) was observed in the peripheral retina. The earliest signs of retinopathy in the noninoculated eye were isolated foci of outer retinal disruption in the posterior retina on day 6. The inflammation accompanying early retinal changes of HSV retinopathy were more severe in the inoculated eye. Electron microscopy of both eyes revealed viral particles in the inner nuclear and ganglion cell layers at the time of outer retinal disruption, but viral particles were seen only rarely in the outer retinal layers at this stage. Early disruption of normal retinal architecture may be due to infection and destruction of Muller cells. The retinopathy progressed in both eyes to total destruction of the retina by day 10. Viral infection of the retinal pigment epithelium occurred, but viral particles were seen only rarely in the underlying choroid. This model may be useful for the study of HSV retinopathy in humans.

Herpetic keratitis in zinc-deficient rabbits.

In a study of 57 rabbits, we found that zinc played a vital role in the growth of the rabbit and in its immunocompetence. Both humoral and cellular immunity were depressed in the zinc-deficient rabbit. Not only did zinc-deficient animals fail to gain weight, differing in that respect from rabbits on a regular diet, but they also had a high death rate, in contrast with no deaths among normal rabbits. Herpes simplex virus keratitis, both epithelial and stromal, was more severe in the zinc-deficient rabbit but was not improved by local zinc replacement (zinc sulphate ointment, 0.05%); Zinc sulphate ointment (1%), which is four times stronger than commercially available zinc ophthalmic preparations, was severely toxic for the rabbit cornea.

Contribution of virus and immune factors to herpes simplex virus type I-induced corneal pathology.

In vivo T-lymphocyte subpopulation depletion techniques were used to identify the roles of L3T4+ (CD4) and Lyt-2+ (CD8) T-lymphocytes in the pathogenesis of corneal stromal disease induced by two different strains of Herpes simplex virus type 1 (HSV-1). Histologic examination of infected corneas revealed significant differences in the composition of the inflammatory corneal infiltrates induced by the RE and KOS strains of HSV-1. The RE strain induced a predominantly polymorphonuclear leukocyte (PMN) infiltrate, which began approximately 1 week after infection and progressed through day 21. Depletion of CD4 cells before corneal infection with RE HSV-1 greatly reduced the incidence and severity of corneal disease; depletion of CD8 cells had no effect. The strain KOS HSV-1 induced an early PMN infiltrate that became predominantly mononuclear by day 21. Depletion of CD4 cells did not change the incidence or severity of KOS HSV-1-induced corneal stromal disease. The corneal lesions of these mice contained numerous CD8 cells. Depletion of CD8 cells before KOS HSV-1 infection of the cornea moderately reduced the incidence of stromal disease. However, in CD8-depleted mice with the disease, PMNs were the most prevalent infiltrating cells, and the disease appeared identical to that seen in RE HSV-1 infected corneas. Simultaneous depletion of CD4 and CD8 cells before KOS HSV-1 infection eliminated stromal disease. However, when T-cell depletion was discontinued in these mice, stromal disease developed in concert with the appearance of T-cells in the lymphoid organs and corneas. Thus, T-lymphocytes are a necessary component of HSV-1 corneal stromal disease. These results further suggest that RE HSV-1 preferentially activates CD4 cells in the cornea, and KOS HSV-1 preferentially activates CD8 cells in the cornea.

The effect of cellular immune tolerance to HSV-1 antigens on the immunopathology of HSV-1 keratitis.

Previous studies have revealed that herpes simplex virus type 1 (HSV-1) corneal stromal lesions do not develop in the absence of a cell-mediated immune (CMI) response to HSV-1 antigens. HSV-1 glycoprotein C (gC) has been shown to play an important role in the induction of the cytotoxic T lymphocyte (CTL) response to HSV-1 infections at anatomical sites other than the eye. Here we report that a deletion mutant lacking gC (gC-39) when used to infect the corneas of A/J mice was a poor inducer of both CTL and delayed type hypersensitivity (DTH) responses. We have also followed histologically and immunohistochemically the course of HSV-1 stromal disease in A/J mice following topical corneal (TC) infection with wild type (WT) HSV-1, TC infection with gC-39 HSV-1, and simultaneous TC and anterior chamber (TC + AC) infection with WT HSV-1. The latter type of infection has been shown to induce a profound state of DTH and CTL tolerance of HSV-1 antigens. Following TC infection with WT HSV-1, stromal disease progressed to severe ulcerative keratitis with neovascularization by day 21. Histologic and immunohistochemical analysis revealed a predominantly mononuclear infiltrate consisting of numerous plasma cells as well as L3T4+ (T helper/inducer) and Lyt-2+ (T suppressor/cytotoxic) T lymphocytes. Following TC infection with gC-39, or simultaneous TC + AC infection with WT HSV-1, the severity of stromal disease did not progress beyond day 7. On day 21, there was at most a mild stromal cellular infiltrate consisting predominantly of polymorphonuclear neutrophils. These findings indicate that early stromal disease consists of a nonspecific inflammatory response, but severe stromal disease involves a CMI response to HSV-1. AC injection of HSV-1 inhibits the CMI response, thereby halting the progression of stromal disease. Similarly, gC-39, a poor inducer of CMI responses, is also a poor inducer of stromal disease.

Herpetic whitlow and heratitis.

Two patients had herpes simplex infection of the fingertips (herpetic whitlow) associated with herpetic keratitis. Both patients were health-care professionals who probably acquired their disease from patients. Herpetic whitlow can be distinguished from a paronychia by the lack of a tense pulp space, formation of vesicles, and serous (rather than purulent) drainage. The fingertip inflammation resolves spontaneously, leaving normal healthy skin, in about two weeks.

Antigens of herpes simplex virus in whole corneal epithelial sheets from mice.

Mice were inoculated with herpes simplex virus in the skin of the snout or by scarification on the cornea and then examined for eye disease using a slit lamp. Whole mounts of corneal epithelium were stained for virus antigens by the peroxidase-antiperoxidase method, and infectious virus was isolated from eyewashings. Antigens were present one day after corneal inoculation, but after inoculation of the snout, there was a delay of three days before antigens were seen. This delay and the distribution of antigens were evidence of zosteriform spread from the snout to the eye via the nervous system. Disease of the cornea varied in severity and timing depending on the site of inoculation. The peroxidase-antiperoxidase method was more sensitive than isolation of virus from eyewashings and allowed the site and distribution of infected cells to be seen.

Epidemiology of ocular herpes simplex. Natural history in Rochester, Minn, 1950 through 1982.

In the period 1950 through 1982, there were 294 episodes of ocular herpes simplex virus infection in 151 residents of Rochester, Minn. Recurrence rates assessed by life-table methods after the first episode were 9.6% at 1 year, 22.9% at 2 years, and 63.2% at 20 years. Recurrence rates appeared to rise following repeated episodes. Ocular herpes simplex affecting both eyes at the same and/or different episodes was seen in 18 patients (11.9%). One fifth of patients had lid involvement alone, while a third had solely superficial corneal involvement. Deep corneal disease or uveitis was relatively uncommon. Therapy during the early period was varied, but significant complications were uncommon. Ninety percent of the eyes maintained visual acuity of 20/40 or better. The economic impact, measured in terms of days of active disease and physician visits, was substantial.

Herpetic ocular infections of childhood.

A series of 21 pediatric patients with ocular herpes simplex infections is reported. Two groups are presented: those with clinical primary herpes and those with documented recurrences. The corneal manifestations including clinical resistance to idoxuridine are presented. Stromal keratitis and visual loss were not marked in the primary group, but were difficult to prevent in those children with recurrences. The problems encountered in the overall management of children with herpetic keratitis are discussed.

Idoxuridine ocular insert therapy. Use in treatment of experimental Herpes simplex keratitis.

Therapy of acute Herpes simplex keratitis in rabbits with idoxuridine-releasing ocular inserts showed that an application rate of 30mug/hr gave significantly better results than conventional treatment with idoxuridine drops and ointment while exposing the eye to 40% less drug. Delivery rates lower than this were equal or not as effective as drop and ointment therapy and rates up to 100 mug/hr did not produce significantly better results than rates of 30mug/hr. Serial viral cultures demonstrated the persistence of virus beyond the period of clinical resolution of disease in all treatment groups, indicating that therapy should be continued longer than apparent resolution of disease.

Antiviral drops: comparative therapy of experimental herpes simplex keratouveitis.

The present, masked, controlled study compares the therapeutic efficacy of guttate 3% vidarabine, 0.1% idoxuridine, and 1% trifluridine in herpes simplex keratouveitis in rabbits. Vidarabine, whether given every hour, every two hours, or every three hours was significantly better than controls but significantly worse than idoxuridine or trifluridine. Trifluridine and idoxuridine were not significantly different from each other. Viral cultures taken at the end of the six-day treatment period were positive in the majority of all treatment groups except for the trifluridine group, which was 100% negative. Although previous studies have shown that vidarabine is very effective as an antiviral ointment, vidarabine drops are not as effective as guttate idoxuridine or trifluridine.

The biology of herpes simplex virus infection in humans.

Herpes simplex virus is a frequent cause of recurrent ocular, oral, genital or cutaneous eruptions in man. Lesions are highly localized and tend to recur at the same site. Among the most consistent factors provoking recurrence is root section of the trigeminal nerve. Clinical and experimental data suggest that herpes simplex virus is commonly resident within the trigeminal ganglia of man, where it may be responsible for recurrent oral or lip lesions, and is less frequently a resident of the second or third sacral ganglia where it might be responsible for genital eruptions. Generally, the trigeminal virus is type 1 and the sacral virus is type 2; the virus is only rarely recoverable from other sensory ganglia. Factors provoking the reactivation from the virus' latent site and the mechanism for reactivation remain largely unknown. Further study is needed to understand the behavior of HSV and other viruses in nervous system tissue.

Necrotizing vaso-occlusive retinitis.

We studied two adult patients with fulminating, necrotizing vaso-occlusive retinitis, and documented the progressive course of retinal necrosis, vitreoretinal interface contraction, and consequent retinal detachment. The systemic criteria for Behçet's disease were present in one patient, and partially fulfilled in the second.

Primary herpes simplex subepithelial dendritic keratitis.

A 37-year-old man developed an acute follicular conjunctivitis with preauricular lymphadenopathy believed to be epidemic keratoconjunctivitis. On the eighth day of his disease, subepithelial dendritic opacities developed in the cornea which were not typical of either epidemic keratoconjunctivitis or herpetic keratitis. A diagnosis of primary herpes simplex virus infection was established by positive viral culture and a rise in serum antibody titer to herpes simplex virus. Subepithelial dendritic keratitis as a manifestation of herpes simplex infection of the cornea has not been previously described. The lesions seen in this patient were not reproducible in rabbits and we believe they represent an unusual host response to the virus. This form of herpetic keratoconjunctivitis is extremely difficult to differentiate from epidemic keratoconjunctivitis. Corticosteroids should be used with caution in cases that are not completely typical of epidemic keratoconjunctivitis.

Herpes simplex type 1 retinitis in an adult with systemic herpes zoster.

A 72-year-old man developed bullous skin lesions two months before he was discovered to have malignant lymphoma. Herpes zoster virus grew from the skin bullae. He developed encephalitis, keratitis in the left eye, and bilateral retinitis 18 months later. Herpes simplex virus type 1 grew from cultures of the eyelid vesicles and corneal scrapings from the left eye. The patient died two years after the diagnosis of malignant lymphoma. Virus particles believed to be herpes simplex virus were demonstrated on electron microscopy in the necrotic retinal cells.

Tissue adhesive arrests stromal melting in the human cornea.

The direct early application of cyanoacrylate adhesive to a prepared ulcer bed and adjacent basement membrane, followed by placement of a bandage lens, gave good results in ten patients with corneal ulceration. The patients had ulceration with keratitis sicca, herpes keratitis, and other surface diseases. Progressive melting was arrested in all cases, and concurrent adjunctive therapies were used as indicated. The technique is quick and simple.

Superinfections in herpes simplex keratitis.

We reviewed 15 cases of culture-proven corneal superinfections in 15 patients (eight men and seven women ranging in age from 41 to 86 years) with recurrent herpes simplex keratitis. The factors that appeared to increase the risk of superinfection were the presence of an epithelial defect (found in all 15 cases), a history of recurrent herpetic keratouveitis (found in ten cases), and the use of topical corticosteroids (found in 13 cases). Eight of the 15 patients were taking antibiotics at the time the superinfections were diagnosed, indicating that topical antibiotics do not provide sufficient protection. Gram-negative rods were found in six cases (Proteus mirabilis, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella oxytoca, Enterobacter cloacae, and Achromobacter sp.). Gram-positive organisms, often in association with another infecting agent, were found in six cases (Staphylococcus epidermidis, three cases; S. aureus, two cases; and Streptococcus sp., two cases). Fungal superinfections were found in three cases (Cephalosporium acremonium, Candida albicans, and Aspergillus fumigatus, one case each). Mycobacterium cheloni was found in two cases.

Infectious crystalline keratopathy.

In three patients (three men, 44, 67, and 83 years old) an unusual keratopathy characterized by white, branching, crystalline stromal opacities produced lesions that were insidious, that increased in size slowly, and that were clinically and histopathologically associated with little corneal inflammation. Intraocular inflammation eventually became evident in two of the patients. The keratopathy developed while the patients were using topical corticosteroids. In two cases, histopathologic studies disclosed accumulations of gram-positive cocci in the corneal stroma; a viridans streptococcus agent was isolated on culture. In one case, the viridans streptococcus was determined to be a dextran producer, which may have contributed to the pathogenesis of the keratopathy. Despite aggressive treatment with a variety of drugs, epithelial healing, and resolution of the corneal infiltrate, residual scarring persisted in two cases and neovascularization and graft edema in one case each.

A systematic approach to the diagnosis and treatment of chronic conjunctivitis.

In 58 patients with chronic conjunctivitis of greater than two weeks' duration, examination included obtaining an ocular and general medical history and performing a complete ophthalmic examination of the external eye. Conjunctival smears were obtained for Gram and Giemsa staining, direct immunofluorescent monoclonal antibody staining for Chlamydia trachomatis and herpes simplex virus, and chlamydial culture. Cultures for bacteria and viruses were obtained in 33 patients. The cause of the chronic conjunctivitis based on clinical and laboratory criteria was established in 40 of 58 (69%) patients: chlamydia, 11 (19%); virus, eight (14%); irritant, six (10%); allergen, four (7%); contact lens, four (7%); bacteria, four (7%); acne rosacea, two (3%); and floppy eyelid syndrome, one (2%). In 18 of 58 (31%) patients, no specific cause was detected. We recommend a systematic approach in the investigation of chronic conjunctivitis. Direct immunofluorescent monoclonal antibody staining is an effective and rapid technique for detecting chronic chlamydial conjunctivitis.

Linear endotheliitis.

We treated six eyes of five patients with linear endotheliitis. This entity appears clinically as a line of keratic precipitates on the corneal endothelium that progresses centrally and is accompanied by peripheral stromal and epithelial edema. All five patients had ocular pain, redness, and photophobia. One eye had an episode of a dendritic lesion typical of herpes simplex. Two eyes had a history of cataract extraction before developing linear endotheliitis. We treated all patients aggressively with a combination of corticosteroids and antiviral agents. Complete resolution of inflammation and edema occurred in all cases. Four patients required the use of oral acyclovir to control the inflammation and prevent recurrence of the disease. Linear endothelitis is a distinct form of endotheliitis that may be associated with herpes simplex virus, and treatment included corticosteroid and antiviral therapy.

The demyelinating effect of corneal HSV infections in normal and nude (athymic) mice.

Nude (athymic) mice and their immune competent Balb/c litter mates were infected with herpes simplex virus (HSV) type I on the scarified cornea. Seven to eight days after infection the trigeminal root entry zone was examined by light and electron microscopy. The immune competent Balb/c litter mates demonstrated marked central nervous system (CNS) demyelination when compared to the T cell-deficient animals who showed mild edematous change and minimal CNS demyelination ultrastructurally 7 days after infection. Viral titers were similar in both groups at this time. These studies further substantiate a role for the cell-mediated immune system in the CNS demyelination 1 week after corneal infection with HSV.